One of the above-mentioned wide discussions is that which handles the sources and primary origins of knowledge through investigations, studies and attempts to discover the primary principles of the powerful intellectual structure with which the human race is endowed. Thus, it responds to the following questions: 'How did human beings come to know? How was their intellectual life formed, including all the thoughts and notions it possesses? And what is the source that provides them with this stream of thought and knowledge?'
Every human being knows numerous things in his life, and numerous forms of thought and knowledge are expressed in his soul. There is no doubt that many kinds of human knowledge grow out of each other. Thus, in forming new knowledge, a human being is assisted by previous knowledge. The issue is to be able to put our finger on the primary threads of thought and on the common source of knowledge in general.
To begin with, we must know that in the main, perception is divided into two kinds. One of them is conception.  This is simple knowledge.  The ether is assent. (p. 58) This is knowledge involving a judgement.  Conception is exemplified in our grasp  of the idea of heat, light or sound. Assent, on the other hand, is exemplified in our judgement  that heat is a power derived from the sun, that the sun is more luminous than the moon, and that the atom is susceptible to explosion. 
We begin now with a study of human conceptions, concentrating on their sources and causes. After that, we will take up assent and knowledge.
Conception and Its Primary Source
By the term 'primary', we mean the real source of simple conceptions or simple knowledge. The human mind contains two kinds of conceptions. One of them is simple conceptual ideas, such as the ideas of 'existence', 'unity', 'heat', 'whiteness', and similar single human conceptions. The other is composite ideas, which are the conceptions that result from a combination of simple conceptions. Thus, you may conceive 'a mountain of soil', and then conceive 'a piece of gold'. After that, you combine these two conceptions. Thus, deriving from this combination a third conception which is (p. 59) 'a mountain of gold'. This third conception is in reality composed of the previous two conceptions; hence, all composite conceptions are reduced to simple conceptual units.
The issue under consideration is the attempt to know the real source of these units and the cause of the arising of these simple conceptions in human knowledge. This issue has an important history in the various stages of Greek, Islamic and European philosophy. Throughout the history of philosophy, it received a number of solutions. These solutions can be summarized in the following theories.
I - The Platonic Theory of Recollection
This theory states that knowledge is a function of the recollection of previous information.  Plato was the founder of this theory. He based it on his specific philosophy of the archetypes.  He believed that the soul has a prior existence. Thus, he believed that prior to the existence of the body, the human soul had existed independently of the body. Since the soul's existence was completely free from matter and its restrictions, it was possible for it to be in touch with the archetypes - that is with the realities that are free from matter. Thus, it was also possible for is to know them. However, when it became necessary for the soul to descend from its immaterial world in order to be conjoined to the body and linked to it in the world of matter, this caused it to lose all its knowledge of the archetypes and fixed realities, and to forget them completely. But the soul can begin to retrieve its knowledge by means of the sense perception of specific ideas and particular things. This is because all such ideas and things are shadows and reflections of those eternal archetypes and realities that are everlasting in the world in which the soul had lived. When is perceives a specific idea, it immediately moves to the ideal reality that it had known before it became attached to the body. On this basis, our knowledge of the universal human being -that is, the universal idea of a human being - would be nothing but a recollection of an abstract reality that we had forgotten. Indeed, we remember it only due to our sense perception of this or that specific human being (p. 60) who reflects that abstract reality in the material world. Thus, universal conceptions are prior to sense perception. And perception is not realized except through the process of retrieving and recollecting such universal conceptions. Rational knowledge is not related to particular things in the sensible realm. Rather, it is only related to those abstract universal realities.
This theory is based on two philosophical propositions. One of them is that the soul exists prior to the existence of the body in a world higher than matter. The other is that rational knowledge is nothing but knowledge of the fixed abstract realities in that higher world - the Platonic technical term for these realities being 'archetypes'.
Both propositions are false, as was pointed out by critics of Plato's philosophy. For the soul, in the rational philosophical sense, is not something that exists in an abstract form and prior to the existence of the body. Rather, it is the result of a substantial movement in matter. The soul begins with this movement as material, characterized by material qualities and subjugated to the laws of matter. By means of this movement and process of completion, it acquires an immaterial existence not characterized by material qualities and not subject to the laws of matter, even though it is subject to the general laws of existence. This philosophical notion of the soul is the only one that can explain the [present] issue, and give a reasonable clarification of the relation between the soul and matter or the soul and the body. As for the Platonic notion, which supposes that the soul has an existence prior to that of the body, it is most incapable of explaining this relation, of justifying the link that exists between the soul and the body, and of clarifying the circumstances under which the soul falls from its own level to that of matter.
Besides, it is possible to explain rational knowledge - with the notion of the archetypes put aside in the field of discussion - (p. 61) by the explanation given in Aristotle's philosophy: namely, that the sensible ideas are the same as the universal ideas that the mind knows after is abstracts them from the proper qualities of individuals, and retains the common idea. The universal human being chat we know is not an ideal reality that we had previously seen in a higher world. Rather, he is the form of this or that human being, after it has been subjected to the process of abstraction by means of which the universal idea is extracted from it. (p. 62)
11 - The Rational Theory
This theory was adopted by a number of prominent European philosophers, such as Descartes,  Kant  and others. It can be summarized in the belief that there are two sources of conceptions. One of them is sense perception. Thus, we conceive 'heat', 'light', 'taste' or 'sound' due to our sense perception of all of that. The other is the innate nature. This is to say that the human mind possesses ideas and conceptions that are not derived from the senses, but are fixed in the innermost being of the innate nature. Thus, the soul draws [certain ideas] from itself. According to Descartes, these innate conceptions are the ideas of Cod, the soul, extension and movement, as well as the ideas that resemble them, and are characterized by complete clarity in the human mind. And, according to Kant, the whole field of conceptual human knowledge and science - including the two forms of time and space, as well as the twelve categories,  for which Kant is known - is innate.
The senses are, on the basis of this theory, the source of understanding the simple conceptions and ideas. However, they are not the only source. Rather, there is also the innate nature that produces in the mind a number of conceptions.
What obliged the rationalists to adopt this theory for explaining human conceptions was this. They did not find a reason for the arising of a number of ideas and conceptions from the senses, since they are non-sensible ideas. Thus, they must be derived essentially from the innermost being of the soul. This makes it clear that the philosophical motive for postulating the rational theory would be completely eliminated if we could explain the mental conceptions solidly, and without need of supposing innate ideas. Because of this, we can refute the rational theory in two ways.
The first is by analyzing knowledge in a way that would attribute all of it to the senses, and facilitate understanding the manner in which all conceptions are produced from the senses. Such an analysis would deny any justification to the theory of innate ideas, since it was based on the complete separation of some ideas from the sphere of the senses. Therefore, if it were possible to extend the reach of the senses to the various areas of conception, there would be no need for innate conceptions. This way was adopted by John Locke  in responding to Descartes and other such rationalists. Later, it was also adopted by those who upheld the empirical principle, such as Berkeley  and David Hume. 
The second way is the philosophical method for responding to [the view of] innate conceptions. It is based on the principle that a multiplicity of effects cannot be the result of chat which is simple, by virtue of the fact of its simplicity. The soul is simple. Therefore, it cannot be a cause in a natural manner of a number of conceptions and ideas. Rather, the existence of such a large number of pieces of knowledge in the soul must be caused by many external factors. These factors are the instrumental senses and the various sensations that occur to them.  (p. 68)
A complete criticism of this proof requires that we explain the principle on which it is based, and give a clarification of the reality and simplicity of the soul. But for this, there is no room here. However, we must point out the following. First, this proof - if one can accept it - does not totally demolish the theory of innate ideas, because it only demonstrates the lack of a multiplicity of innate pieces of knowledge, but does not prove that the soul does not naturally possess a limited [number of] conceptions  concordant with its unity and simplicity, and resulting in a number of other conceptions independent of the senses. In the second place, we would like to clarify that if the rational theory means that in the human soul there are innate ideas in actuality, then it becomes possible for the proof presented above to respond to this theory as follows. The soul is simple in essence; so, how could it produce that large number of innate ideas? Indeed, if the rationalists were truly inclined to believe that, then our human inner feeling would be sufficient for rejecting their theory. This is because all of us know that at the moment human beings [begin] to exist on the face of the earth, they do not possess any idea, regardless of how clear and general it is in the human mind:
God brought you out of your mothers' abdomens when you did not know anything. He gave you hearing, vision and hearts, in the hope that you will be grateful. 
Still, another interpretation of the rational theory can be recapitulated in the consideration that innate ideas exist in the soul potentially, and that they acquire the quality of being actual by the development and mental integration of the soul. Thus, innate conceptions are not produced by the senses. Rather, the soul contains them without attending to them. However, with the integration of the soul, these conceptions become knowledge, attended to and clear, as is the case of the knowledge and information that we recollect and, hence, reawaken once again after they had been latent and potential. (p. 64)
In light of this interpretation, the rational theory cannot be rejected on the basis of the philosophical demonstration or scientific evidence which has already been mentioned.
III - The Empirical Theory
This theory states that only sense perception supplies the human mind with conceptions and ideas, and that mental power is that which reflects in the mind the various sense perceptions. Thus, when we perceive a thing, we can have a conception of it - that is, we can grasp its form mentally. But the ideas that lie outside the province of the senses cannot be created by the soul, nor constructed by it essentially and independently. According to this theory, the mind merely manages the conceptions of sensible ideas. It does this either (1) by combination and division, so that it combines those conceptions, or divides every one of them. Thus, it conceives 'a mountain of gold', or divides 'the tree', that is had known into pieces and parts. Or (2) the mind manages the conceptions of sensible ideas by abstraction and universalization, so that it separates the qualities of the form, and abstracts the form from its particular qualities; with the result that [the mind] can form from it a universal idea. This is exemplified in conceiving Zayd, and discounting all that which distinguishes him from 'Umar. By means of this process of subtraction, the mind retains an abstract idea that applies to both Zayd and 'Umar.
Perhaps the first one to advocate this empirical theory was John Locke, the eminent British philosopher who emerged in a philosophical period pervaded by the Cartesian notions of innate ideas. Thus, Locke began to refute these notions. For this purpose, he put forth in his book, Essay on Human Understanding, a detailed philosophy of human knowledge. In this book, he attempted to attribute all conceptions and ideas to the senses. Lacer, this theory became widely spread among European philosophers, and, to some extent, it destroyed the theory of innate ideas. A number of philosophers adopted its most extreme (p. 65) forms. This led to very dangerous philosophies, such as the philosophies of Berkeley and David Hume, as we will show later, God willing.
Marxism adopted this theory in its explanation of human knowledge. This was consistent with its view of human consciousness as a reflection of objective reality. Thus, all knowledge can be attributed to a reflection of a particular reality. Such a reflection occurs by means of the senses. It is not possible for knowledge and thought to be related to anything that falls outside the limits of sensible reflections. Hence, we do not conceive anything other than our sense perceptions which indicate objective realities that exist in the external world.
Georges Politzer  said the following:
But what is the point of the origin of consciousness or thought? It is sense perception. Further, the source of the sense perceptions chat human beings experience is grounded in their natural needs. 
The Marxist view, therefore, can be interpreted to mean that there is no source for the content of our consciousness other than the objective particulars which are given to us by the external circumstances that we live. These particulars are given to us through sense perceptions. That is all there is to this matter. 
In an attempt to clarify the Marxist view of this matter, Mao Tse-tungn  made the following statement: 'The source of all knowledge lies hidden in the perceptions by the bodily human sense organs of the objective world which surrounds us.' 
Thus, the first step in the process of acquiring knowledge is (p. 66) the primary contact with the external environment - this is the stage of sense perception. The second step is the accumulation, the lining up and the organizing of the information which we gather from sense perception. 
The empirical theory focuses on experimentation; for scientific experiments have shown chat the senses [provide] the perceptions chat produce the human conceptions. Thus, he who is deprived of any sense cannot conceive the ideas that are related to that specific sense.
Such experiments - if sound- prove scientifically only that the senses are the primary source of conception. Were it not for the senses, no conceptions would have existed in the human mind. However, such experiments do not strip the mind of the ability to produce from the sensible ideas new ideas not known by the senses. Therefore, it is not necessary that all our simple conceptions be preceded by the sense perception of their ideas, as the empirical theory claims. In light of the above-mentioned experiments, the senses are the primary structure on the basis of which the human conception is established. But this idea does not mean that the mind is void of agency and innovation of new conceptions in light of the conceptions that are derived from the senses.
It is possible for us to show the failure of the empirical theory in its attempt to attribute all the human conceptual notions to the senses by investigating a number of the notions of the human mind, such as the following: 'cause' and 'effect', 'substance' and 'accident', 'possibility' and 'necessity', 'unity' and 'multiplicity', 'existence' and 'non-existence', as well as other similar notions and conceptions.
We all know that the senses grasp the cause and effect themselves. (p. 67) Thus, by means of our sight, we know that a pencil falls to the ground if the table on which it was placed is pulled from underneath it. Also, by means of touch, we know that water becomes hot when it is placed on fire. Similarly, we know chat bodily particles expand in hot weather. In these examples, we perceive two successive phenomena, but we do not perceive a specific relation between the two. This relation is what we call 'causality'. By 'causality' we mean the influence of one of these phenomena on the other and the need of the other for it, in order that the other exists.
The attempts that seek to extend the province of the senses to cover causality itself and to consider it as an empirical principle are based on avoiding the depth and precision in the knowledge of the realm of the senses and the ideas and limits it includes. Regardless of the proclamations made by the empiricists - namely, chat human experiences and the experimental sciences, which are based on the senses, are what clarify the principle of causality, and make us realize how specific material phenomena arise from other similar phenomena - I say that regardless of such proclamations, the empiricists will not be successful, as long as we know that scientific experiments cannot reveal by means of the senses anything except the succession of phenomena. Thus, we can know that by placing water on the fire, the water gets hot. Then we multiply its temperature. At last, we perceive the boiling of the water. The empirical side of the experiment does not disclose that boiling is produced because the temperature reaches a specific degree. But if our empirical experiments fall short of disclosing the notion of causality, then how did this nation develop in the human mind, so that we began to conceive it and think about it?
David Hume, one of the advocates of the empirical principle, was more precise than others in applying the empirical theory. He knew that causality, in the real sense of the term, cannot be known by the senses. Because of this, he rejected the principle of causality and attributed it to the habit of the association of ideas, saying that I see the billiard ball move, and then encounter another ball that, in turn, moves. But in the movement of the former ball, there is nothing that reveals to me the necessity of the movement of the latter. The internal senses also tell me that the movement of the organs follows upon an order from the will. However, they do not give me a direct knowledge of a necessary relation between the movement and the order.  (p. 68)
But the rejection of the principle of causality does not at all minimize the difficulty that faces the empirical theory. The rejection of this principle as an objective reality means that we do not believe that causality is a law of objective reality, and that we are unable to know whether the phenomena are linked by necessary relations that make some of them effects of some others. However, the principle of causality as an idea assented to is one thing, while the principle of causality as a conceptual idea is another. Suppose, for example, that we do not assent to the fact that some sensible things cause some other sensible things, and chat we do not form an assent concerning the principle of causality, would this mean that we do not have a conception of the principle of causality either? If we do not have such a conception, then what is it chat was rejected by David Hume? Can a human being reject something of which he has no conception?
The undeniable truth is chat we conceive the principle of causality, whether or not we assent to it. Further, the conception of causality is not composed of the conceptions of the two successive things. When we conceive the causation of a specific degree of temperature for boiling, we do not intend by this causation an artificial composition of the idea of temperature and that of boiling. Rather, we intend a third idea that exists between the two. From where, then, does this third idea that is not known by the senses come, if the mind does not have the ability to create non-sensible ideas? We face the same difficulty with regard to the other notions mentioned earlier;  since all of them are non-sensible. Thus, it is necessary to cast aside the purely empirical explanation of human conceptions and to adopt the dispossession theory (nazariyyat al-intiza).
IV - The Dispossession Theory
This is the theory of the Islamic philosophers in general. It can be summarized in the division of the mental conceptions into the following two kind:: primary conceptions and secondary conceptions.
The primary conceptions are the conceptual foundation of the human mind. (p. 69) These primary conceptions are produced from the direct genre perception of their content. Thus, we conceive heat because we had known it by means of touch. And, we conceive a color because we had known it by means of vision. Again, we conceive sweetness because we had known it by means of taste. Similarly, we conceive an odor because we had known it by means of smell. The same is true of all the ideas that we know by means of our senses. The sense perception of every one of them is the cause of their conception and the presence of an idea about them in the human mind. These ideas form the primary foundation of conception. On the basis of this foundation, the mind establishes the secondary conceptions. With this, the stage of innovation and construction begins - the theory under consideration gives this stage the technical name 'dispossession'. The mind produces new notions from those primary ideas. These new ideas fall outside the scope of the senses, even though they are derived and extracted from the ideas that are given to the mind and to thought by the senses.
This theory is consistent with demonstration and experiments. It is possible for it to give a solid explanation of all the conceptual units. In light of this theory, we can understand how the notions of cause and effect, substance and accident, existence and unity came about in the human mind. All of them are dispossessed notions that the mind invents in light of the sensible ideas. Thus, we perceive the boiling of water [at sea level] when its temperature reaches one hundred degrees [centigrade]. Further, our perception of rhea two phenomena -the phenomena of boiling and that of temperature - may be repeated a thousand times, yet without our ever perceiving the causation of temperature to boiling. Rather, the mind dispossesses the notion of causality from the two phenomena that are offered by the senses to the field of conception.
Due to the limitation of space, we cannot discuss the manner, kinds and divisions of mental dispossessions. This is because in this brief investigation of ours, we are not to discuss anything other than the main points. (p. 70)
Assent and Its Primary Source
We move now from the investigation of simple knowledge (conception) to the investigation of knowledge as assent that involves a judgement, and by means of which human beings obtain objective knowledge.
Every one of us knows a number of propositions and assents to them. Among such propositions, there are those in which the judgement is based on particular objective realities, as in our statements: 'The weather is hot.' 'The sun is out.' Because of this, the proposition is called 'particular'. There are also propositions in which the judgement is based on two general ideas, as in our statements: 'The whole is greater than the part.' 'One is half of two.' 'The indivisible part is impossible.' 'Heat causes boiling.' 'Coldness is a cause of solidification.' 'The circumference of the circle is greater than its diameter.' 'A mass is a relative reality.' The same is true of [other] philosophical, physical and mathematical propositions. These propositions are called 'universal' or 'general'. The problem that we encounter is that of knowing the origin of knowledge as assent and the principles on which the edifice of human knowledge is based. What, then, are the primary threads from which that large group of judgements and knowledge is woven? Also, what is the principle that human knowledge reaches in explanation, and is considered a general primary criterion for distinguishing truth from other things?
There are a number of philosophical doctrines concerned with this issue. Of these doctrines we will take up for study the rational doctrine and the experimental doctrine. The former is the doctrine on which Islamic philosophy, as well as the method of Islamic thinking in general, is based. The latter is the prevalent view in a number of materialistic schools, of which the Marxist school is one.
I - The Rational Doctrine
In the view of the rationalists, human knowledge is divided into two kinds. One of them is necessary knowledge, or intuitive knowledge. (p. 71) By 'necessity' here, we mean that the soul is obliged to accept a certain proposition, without having to require any evidence or a demonstration of its soundness. Rather, it finds in its own nature the necessity for believing it, in a manner not in need of any evidence or conformation. This is exemplified in the soul's belief in, or knowledge of, the following propositions: 'Negation and affirmation are not true of the same thing [at the same time].' 'That which is originated does not exist without a cause.' 'Contrary qualities are not in harmony in the same subject.' 'The whole is greater than the part.' 'One is half of two.'
The ocher kind consists of theoretical knowledge and information. There are a number of propositions whose truth the soul does not believe except in light of previous knowledge and information. Thus, the soul's making of judgements in those propositions depends on the process of thinking and derivation of the truth from prior truths that are clearer than they are, as in the following propositions: 'The earth is spherical.' 'Motion is a cause of heat.' '[The infinite] regress is impossible.' 'Bodily particles expand by heat.' 'The angles of a triangle are equal to two right angles.' 'Matter is transformable into energy.' The same is true of similar philosophical and scientific propositions. When such propositions are presented to the soul, the soul does not reach a judgement concerning them except after reviewing other information. Because of this, the theoretical knowledge depends on the necessary primary knowledge. Therefore, if such primary knowledge is removed from the human mind, one would not be able at all to attain any theoretical knowledge, as we will show later, God willing.
Thus, the rational doctrine shows chat the cornerstone of knowledge is the primary information. On the basis of such information, the superstructures of human thought, referred to as 'secondary information', are built.
The operation through which one derives theoretical knowledge from previous knowledge is the operation that we call 'thought' or 'thinking'. Thinking is an effort that the mind makes for the purpose of acquiring a new assent or a new knowledge from some of its previous knowledge. This means that when a human being attempts to deal with a new issue, such as the origination of matter, in order to know (p. 72) whether matter is originated or old, he has two things to consider. One of them is a specific attribute - that is, the origination. And the other is the thing which seeks actualization by means of acquiring that attribute - this thing being 'matter'. Since this proposition is not one of the rational primary propositions, a human being, therefore, would naturally hesitate to judge and to accept the origination of matter. He then resorts to his previous knowledge to try to find in it something on which he can base his judgement and utilize as an intermediary for knowing the origination of matter. With this, the process of thinking begins by looking over the previous information. Let us suppose, for example, that among such truths that the thinker already knows, there is the substantial movement that determines that matter is a continuous motion and a constant renewal. The mind, then, grasps this truth when this truth appears to it in the mental presentation, and makes it a link between matter and origination. For, since matter is renewable, is must be originated. This is because continuous change means continuous creation. At that point, a new knowledge is acquired by the human being, this knowledge being that matter is originated, because it is moveable and renewable, and whatever is renewable is originated.
This is how the mind is able to draw a link between origination and matter - the link being the motion of matter. It is this motion that makes us believe that matter is originated, because we know that everything moveable is originated.
Due to this, the rational doctrine asserts chat the causal relation in human knowledge is between some information and some other. For all knowledge is only produced by previous knowledge. The same is true of this previous knowledge, [and so on], until the progressive series reaches the primary rational knowledge that does not arise from previous knowledge. For this reason, this primary knowledge is considered the primary cause of knowledge.
This primary cause of knowledge is of two kinds: it is either (1) a basic condition of all human knowledge in general, or (2) a cause of a part of the information. The former is the principle of non-contradiction. This principle is necessary for all (p. 78) knowledge. Without is one cannot be sure that a certain proposition is not false, regardless of how much evidence one has for its truth and soundness. This is because, if contradiction were possible, then it would be possible for the proposition to be false at the same time in which we prove its truth. This means that the collapse of the principle of noncontradiction strikes a blow at all philosophical and physical propositions, regardless of their kind. The latter kind of primary knowledge is the rest of the necessary knowledge of which every piece is a cause of a group of pieces of information.
On the basis of the rational doctrine, the following [truths] hold: first, the primary criterion of human thinking in general is the necessary rational knowledge. It is the fundamental pillar that is indispensable in every field. The truth or falsity of every idea must be measured in light of it. Due to this, the field of human knowledge becomes wider than the sphere of the senses and experimentation. This is because it provides human thinking with powers that extend to truths and propositions that lie beyond matter, and achieves for metaphysics and the higher philosophy the possibility of knowledge.
The experimental doctrine is the contrary of this. It distances the metaphysical issues from the field of discussion, because they are issues which are not subject to experimentation, and to which scientific understanding does not extend. Thus, it is not possible to be sure whether they are negations or affirmations, as long as experimentation is the only primary criterion, as the experimental doctrine claims.
Second, in the view of the rationalists, the progression of thought moves from general propositions to more particular propositions - that is, from universal propositions to particular propositions. Even in the experimental field, which appears at first sight to be one in which the mind moves from individual experimental subjects to general principles and laws, movement and progression occur from the general to the particular. This will be shown in our response to the experimental doctrine. (p. 74)
No doubt, you remember the example already mentioned of the knowledgeability of thought, how we moved in it from a general knowledge to a particular knowledge. We acquired the knowledge that 'matter is originated' from the knowledge that 'everything that changes is originated'. Thought began with this universal proposition, 'Everything that changes is originated', and then moved from it to a more particular proposition, 'Matter is originated'.
Finally we must warn that the rational doctrine does not neglect the powerful role of experimentation in the human sciences and knowledge, the enormous services that experimentation offers to mankind, and the secrets of the universe and the natural mysteries that it discloses. However, according to this doctrine, experimentation alone could not have played this powerful role; because for the derivation of any such scientific truths from it, it requires the application of the necessary rational laws. This means that the derivation is achieved in light of the primary knowledge. It is not possible for experiments in themselves to be the original source and the primary criterion for knowledge. For it is analogous to the test that the doctor gives the patient. It is this test that provides the doctor with the opportunity of discovering the nature of the disease and its accompanying complications. However, this test would not help discover that, were it not for the previous information and knowledge that the doctor has. Had he not had such information, his test would have been null and empty of any benefit. Similarly, human experiments, in general, do not pave the way for conclusions and truths except in light of previous rational information.
11 - The Empirical Doctrine
This doctrine states that experience is the primary source of all human knowledge. For that, it relies on the assertion that when human beings are deprived of the various kinds of experiences, they do not know any truth, regardless of its clarity. This shows that  human beings are born without any innate knowledge. They begin their awareness and knowledge as soon as they begin (p. 75) their practical lives. Their knowledge widens as their experiences widen, and their knowledge becomes varied in kind as their. experiences take on different forms.
The empiricists do not admit necessary rational knowledge prior to experience. Rather, they consider experience as the only basis of sound judgement and the general criterion in every field. Even those judgements that the rational doctrine alleges to be necessary knowledge must, [according to the empiricists], be subject to the empirical criterion, and must be admitted in accordance with the determination of experience. This is because human beings do not have any judgement whose confirmation does not require experience. This results in the following:
First, the, power of human thinking is delimited by the limits of the empirical field; so that, any metaphysical investigation or study of metaphysical issues becomes useless. [In this, the empirical doctrine] is exactly the contrary of the rational doctrine.
Second, the movement of thought progresses in a way contrary to the manner asserted by the rational doctrine. Thus, whereas the rational doctrine asserts that a thought always moves from what is general to what is particular, the empiricists assert that it moves from what is particular to what is general; that is, from the narrow limits of experiments to universal laws and principles. It always progresses from the empirical particular truth to the absolute truth. The general laws and universal principles that human beings have are nothing but the result of experiences. The consequence of this is a progression of induction from  individual things to a discovery of general objective truths.
For this reason, the empirical doctrine relies on the inductive method in [its] search for evidence and in thinking, since this method is one that ascends from the particular to the universal. It rejects the principle of syllogistic  reasoning, by virtue of which thought moves from the general to the particular, as in the following syllogistic figure:  'All human beings are mortal.' 'Muhammad is a human being.' 'Therefore, Muhammad is mortal.' (p. 76) This rejection depends on the fact that this syllogistic figure does not lead to new knowledge in the conclusion, even though it is a condition of demonstration that it leads to a new conclusion not contained in the premises.  Thus, the syllogism in its above-mentioned form falls into the kind of fallacy called 'begging the question' (al-musadara 'ala al-matlub). This is because if we accept the premise 'all human beings are mortal', we then include in the subject, 'human being', all human individuals. After that, if we follow this premise by another: 'Muhammad is a human being,' we are then either aware that Muhammad is one of the human individuals we intended in the first premise - with this, we would also be aware that he is mortal before we state this truth in the second premise - or we are not aware of that. In this case, we would have generalized the first premise without justification, because we had not yet known that mortality is applicable to all human beings, as we claimed.
This is a brief exposition of the empirical doctrine which we find ourselves obliged to reject for the following reasons. First, is this principle itself (experience is the primary criterion for discerning the truth) primary knowledge that human beings acquire without previous experience? Or is it, in turn, like other human knowledge, in being neither innate nor necessary? If it is primary knowledge previous to experience, then the empirical doctrine, which does not affirm primary knowledge, is falsified; and the presence of necessary human information as independent of experience is affirmed. But if this knowledge is in need of previous knowledge, this would mean that we do not know at first that experience is a logical criterion whose truth is secured. How, then, can one demonstrate its truth, and consider it a criterion of experience when its truth is not yet certain?
In other words, if the above-mentioned principle, which is the cornerstone of the empirical doctrine, is false, then the empirical doctrine collapses due to the collapse of its main principle. (p. 77) If, on the other hand, it is sound, then it will be appropriate for us to inquire about the reason that led the empiricists to believe that this principle is sound. For if they were assured of its soundness without experience, this would mean that it is an intuitive proposition, and that human beings possess truths that lie beyond the realm of experience. If, however, they were assured of its soundness by a previous experience, this would be impossible, because experience cannot ascertain its own value.
Second, the philosophical notion that is based on the empirical doctrine is incapable of affirming matter. The reason for this is that matter cannot be disclosed by means of pure experience. Rather, all that appears to the senses in the experiential fields are only the phenomena and accidents of matter. Regarding matter itself - namely, the material substance that those phenomena and qualities exhibit - it is not known by the senses. The rose that we see on the tree, for example, or that we touch with our hand [is such that] we only have sense perception of its odor, color and softness. Even if we taste it, we will [only] have sense perception of its flavor. But in none of these cases do we have sense perception of the substance in which all these phenomena meet. Rather, we know this substance only by means of a rational proof that is based on primary rational knowledge, as we will point out in the forthcoming discussions. For this reason, a number of empiricists or experientialists denied the existence of matter.
The only ground for asserting [the existence of] matter are the primary rational propositions. Were it not for them, it would not be possible for the senses to confirm to us the existence of matter behind the beautiful smell, the red color and the specific flavor of the rose.
Thus, it becomes dear to us that the metaphysical realities are not the only realities whose demonstration requires the pursuit of the rational method in thinking, but also matter itself.
As a matter of fact, we raise this objection against those who believe on the basis of the principles of the empirical doctrine that a material substance exists in nature. But this objection does not touch those who interpret nature (p. 78) as mere phenomena that occur and change, without admitting a subject in which such phenomena meet.
Third, if the mind were confined to the limits of experience and did not have knowledge independent of experience, then it would not be possible for it at all to assert the impossibility of anything. This is because impossibility, in the sense of 'non-possibility of the existence of a thing', is not within the scope of experience; nor is it possible for experience to disclose it. The most that experience can show is the non-existence of specific things.  However, the non-existence of a thing does not mean its impossibility. There are a number of things whose existence is not disclosed by experience. Rather, experience shows their non-existence in their specific area. In spite of that, we do not consider them impossible; nor do we strip them of the possibility of existence, as we do in the case of impossible things. There is a clear difference between the collision of the moon with the earth, the existence of people on Mars, or the existence of a human being who can fly due to specific flexibility in his muscles, on the one hand,  and the existence of a triangle having four sides, the existence of a part greater than the whole, or the existence of the moon in the case of its non-existence, on the other hand.  None of these propositions has been actualized, and none of them has been subject to experience. Thus, if experience alone were the main source of knowledge, then we would not be able to distinguish between the [abovementioned] two groups [of propositions]. This is because the word 'experience' is the same in both of them. In spite of this, we all see the clear difference between the two groups. The first group has not been actualized; however, it is possible essentially. As for the second group, it is not only nonexistent, but it cannot exist at all. The triangle, for example, cannot have four sides, whether or not the moon collides with the earth. This judgement of impossibility cannot be interpreted except in light of the rational doctrine, as a rational knowledge independent of experience. Because of this, the empiricists are left with two alternatives only. They must either admit the impossibility of specific things, such as the things mentioned in the second group, (p. 79) or they must deny the notion of impossibility of all things.
If they accept the impossibility of things, such as those which we have mentioned [in the second group], their acceptance must rely on independent rational knowledge, and not on experience. The reason is that the nonappearance of a thing in experience does not indicate its impossibility.
If, on the other hand, they deny the notion of impossibility, and do not admit the impossibility of anything, regardless of how strange that may be to the mind, on the basis of such a denial, there would remain no difference between the two groups already presented, concerning which we have realized the necessity of differentiating between them. Further, if the notion of impossibility is eliminated, then contradiction - namely, the simultaneous existence and non-existence of a thing, or the simultaneous truth and falsity of a proposition - will not be impossible. But the possibility of contradiction leads to the collapse of all knowledge and' science, and to the failure of experience to remove doubt and hesitancy in any scientific field. This is because no matter how many experiments and pieces of evidence confirm the truth of a specific scientific proposition, such as 'Gold is a simple element', we still cannot be certain that this proposition is not false, as long as it is possible for things to be contradictory and for propositions to be true and false at the same time.
Fourth the principle of causality cannot be demonstrated by means of the empirical doctrine. As the empirical theory is incapable of giving a sound justification of causality as a conceptual idea, so also is the empirical doctrine incapable of demonstrating it as a principle or an idea of assent. For experience cannot clarify anything to us except a succession of specific phenomena. Thus, by means of it we know that water boils when it is heated to 100 degrees [centigrade], and that it freezes when its temperature reaches below 0 degrees [centigrade]. As for one phenomenon causing the other, and the necessity between the two, this is something not disclosed by the means of experience, regardless of how precise it is and regardless of our repetition of the experience. But if the principle of causality collapses, all the natural sciences also collapse, as you will learn later.
Some empiricists, such as David Hume and John Stuart Mill (p. 80), have admitted this truth. That is why Hume interprets the element of necessity in the law of cause and effect to be due to the nature of the rational operation that is employed in reaching this law. He says that if one of the operations of the mind is employed for the purpose of obtaining this law - adding that if one of the operations of the mind always leads to another operation that follows it immediately -then, with the passage of time, a constant strong relation, which we call 'the relation of association of ideas', develops between the two operations. This association is accompanied by a kind of rational necessity, such that the idea that is linked to one of the two mental operations occurs in the mind, as does the idea that is linked to the other operation. This rational necessity is the basis of what we call the necessity that we grasp in the link between the cause and the effect. There is no doubt that this explanation of the relation between the cause and the effect is incorrect for the following reasons.
First, from this explanation, it follows that we do not reach the general law of causality except after a series of repeated events and experiments that fasten in the mind the link between the two ideas of cause and effect, even though that is not necessary. For the natural scientist is able to infer a relation of causality and necessity between two things that occur in one event. His certitude is not at all strengthened [later] beyond what it was when he observed the event for the first time. Similarly, the relation of causality is not strengthened by the repetition of other events involving the same cause and effect.
Second, let us put aside two successive external events and turn our attention to their two ideas in the mind - namely, the idea of cause and that of effect. Is the relation between them one of necessity or one of conjunction, as our conception of iron is conjoined to our conception of the market in which the iron is sold? If it is a necessary relation, then the principle of causality is confirmed, and a non-empirical relation between two ideas - that is, the relation of necessity - is implicitly admitted. (p. 81) [In this case], whether necessity is between two ideas or between two objective realities, it cannot be demonstrated by sense experience. If, on the other hand, the relation is a mere conjunction, then David [Hume] did not succeed in explaining, as he intended, the element of necessity in the law of cause and effect.
Third, the necessity, which we grasp in the relation of causality between a cause and an effect, involves no influence at all on requiring the mind to invoke one of the two ideas when the other idea occurs in the mind. That is why this necessity that we grasp between the cause and the effect is the same, whether or not we have a specific idea about the relation. Thus, necessity of the principle of causality is not a psychological necessity, but an objective necessity.
Fourth, the cause and effect may be completely conjoined, yet in spite of that, we grasp the causation of the one on the other. This is exemplified m the movement of the hand and that of the pencil during writing. These two movements are always present at the same time. If the source of necessity and causality were the succession of one of the two mental operations after the other by means of association, then it would not be possible in this example for the movement of the hand to play the role of the cause loll the movement of the pencil; for the mind grasps the two movements at the same time. Why then should one of them be posited as a cause and the other as an effect?
In other words, explaining causality as a psychological necessity means that the cause is considered as such, not because in objective reality it is prior to the effect and is productive of it, but because knowledge of it is always followed by knowledge of the effect by means of the association of ideas. Due to this, the former is the cause of the latter. This explanation cannot show us how the movement of the hand becomes a cause of the movement of the pencil, even though the movement of the pencil does not succeed the movement of the hand in knowledge. Rather, the two movements are known simultaneously. Thus, if the movement of the hand does not have actual priority and objective causality over the movement of the pencil, it would not have been possible to consider it as a cause. (p. 82)
Fifth, it is often the case that two things are associated without the belief that one of them is a cause of the other. If it were possible for David Hume to explain the cause and effect as two events whose succession we often grasp, such that a link of the type of association of ideas occurs between them in the mind, then the night and day would be of this sort. As heat and boiling are two events that have succeeded each other, until an associational link developed between them, the same must be true of the night and day, their succession and their association, even though the elements of causality and necessity that we grasp between heat and boiling are non-existent between the night and day. The night is not a cause of the day, nor the day a cause of the night. It is not possible, therefore, to explain these two elements by the mere repeated succession which leads to the association of ideas, as Hume tried to do.
We conclude from this that the empirical doctrine unavoidably leads to the elimination of the principle of causality and to the failure of demonstrating necessary relations between things. But if the principle of causality is eliminated, all the natural sciences will collapse, since they depend on it, as you will know.
The natural sciences, which the empiricists seek to establish on the basis of pure experimentation, are themselves in need of primary rational principles that are prior to experimentation. This is because the scientist carries out his experiment in his laboratory on limited objective particulars. Then he puts forward a theory for explaining the phenomena that the experiment in the laboratory had disclosed, and for justifying them by one common cause. This is exemplified in the theory that states that the cause of heat is motion, on the basis of a number of experiments interpreted in this way. It is our right to ask the natural scientist about how he offers this theory as a universal law applicable to all circumstances resembling those of the experiment, even though the experiment did not apply except to a number of specific things. Is it not the case, then, that this generalization is based on a principle stating that similar circumstances and things alike in kind and reality must share in laws (p. 83) and decrees? Here, once again, we inquire about how the mind reached this principle. The empiricists cannot claim that it is an empirical principle. Rather, it must be a piece of rational knowledge that is prior to experimentation. The reason is that if it were supported by experimentation, then the experimentation on which this principle is based also, in turn, treats only specific subjects. How, then, can a general principle be based on it? Thus, the establishment of a general principle or a universal law in light of one or more experiments cannot be accomplished except after admitting prior rational knowledge.
With this, it becomes clear that all the empirical theories in the natural sciences are based on a number of pieces of rational knowledge that are not subject to experimentation. Rather, the mind accepts them immediately. They are the following:
If the scientist accepts these pieces of knowledge that are prior to experimentation, and then carries out his various experiments on the kinds and divisions of heat, he can, in the last analysis, postulate a theory for explaining the different kinds of heat by one cause, such as motion, for example. On the whole, it is not possible to postulate this theory as a decisive and an absolute one. The reason is that it can be such only if it is possible for one to be certain of the absence of another explanation of those phenomena, and of the incorrectness of explaining them by another cause. However, in general, this is not determined by experiments. (p. 84) That is why the conclusions of the natural sciences are, for the most part, presumptive, due to a deficiency in experiments, and to an incompleteness in the conditions that make them decisive experiments.
It becomes clear to us from what has preceded that the inference of a scientific conclusion from an experiment is always dependent on syllogistic reasoning in which the human mind moves from the general to the specific, and from the universal to the particular, exactly as viewed by the rational doctrine. The scientist is able to draw the conclusion in the above example by moving from the already mentioned three primary principles (the principle of causality, the principle of harmony, and the principle of non-contradiction) to that specific conclusion in accordance with the syllogistic approach.
Regarding the objection raised by the empiricists against the method of syllogistic reasoning- namely, that the conclusion in it is nothing but an echo of one of the two premises, that is, the major premise, and a repetition of it- it is a bad objection, according to the teachings of the rational doctrine. This is because if we intended to demonstrate the major premise by experiments, and had no other criterion, then we would have to examine all the divisions and kinds, in order to be certain of the soundness of the judgement. The conclusion then would have been also determined in the major premise itself. But if the major premise were a piece of rational knowledge, which we grasp without need of experiments, such as the primary intuitive propositions and the rational theories that are derived from such propositions, then he who seeks to demonstrate the major premise does not need to examine the particulars so that the conclusion is necessitated to take on the quality of repetition and reiteration.  (p. 85)
Once again, we assert that we do not deny the great value of experience for humanity and the extent of its service in the fields of knowledge. However, we wish to make the empiricists understand that experiments are not the primary criterion and the fundamental source of human thought and knowledge. Rather, the primary criterion and the fundamental source are rational primary information, in whose light we acquire all other information and truths. Even experience itself is in need of such a rational criterion. Thus, we and others alike are required to admit this criterion on which the principles of our metaphysical philosophy are based. If, after that, the empiricists attempt to deny this criterion in order to falsify our philosophy, they would be, at the same time, attacking the principles that are the foundation of the natural sciences, and without which the empirical experience is completely fruitless.
In light of the rational doctrine, we can explain the quality of necessity and absolute certainty that distinguish mathematics from the propositions of the natural sciences. This distinction is due to the fact that the necessary mathematical laws and truths are supported by the primary principles (p. 86) of the mind, and do not depend on the discoveries of experiments. The scientific propositions are contrariwise. Thus, the expansion of iron due to heat is not one of the propositions that are given by those principles with no mediation, but is based on experimental propositions. The decisive rational character is the secret of the necessity and absolute certainty in the mathematical truths.
If we study the difference between the mathematical and the natural propositions in light of the empirical doctrine, we will not find a decisive justification for this difference, as long as experience is the only source of scientific knowledge in the two fields.
Some of the defenders of the empirical doctrine have tried to explain the difference on a doctrinal basis by saying that the mathematical propositions are analytic, and that it is not their function to come up with something new. When we say, for example, 'Two plus two equals four,' we do not say anything against which we can test the degree of our certainty, since 'four' is itself another expression for 'two' plus 'two'. Put clearly, the above-mentioned mathematical equation is nothing other than 'Four equals four'. All mathematical propositions are an extension of this analysis. However, this extension varies in the degree of its complexity.
The natural sciences, on the other hand, are not of this sort. The reason for this is that their propositions are composite; that is, the predicate in them adds new information to the subject. This is to say that it provides new
information on the basis of experiments. Thus, if you say, 'Water boils under such and such a pressure; that is, when its temperature, for example, reaches 100 degrees [centigrade]', then I would be informed that the term 'water' does not include the terms 'temperature" pressure', and 'boiling'. Because of this, the scientific propositions are subject to falsity and truth.
But, it is our right to remark concerning this attempt at justifying the difference between the mathematical and the natural propositions that the consideration of the former as analytic does not explain the difference on the basis of the empirical doctrine. Suppose that 'Two plus two equals four' is another expression for our statement, 'Four is four'. This would mean that this mathematical proposition depends on accepting the principle of non-contradiction; otherwise, 'four' may not be itself, if contradiction were (p. 87) possible. According to the teachings of the empirical doctrine, this principle is not rational and necessary; for it denies all prior knowledge. Rather, it is derived from experience, as are the principles on which the scientific propositions in the natural sciences are based. Thus, the problem remains unsolved, as long as both mathematics and the natural sciences are dependent on empirical principles. Why, then, are the mathematical propositions distinguished from other propositions by absolute necessary certainty?
Further, we do not admit that all mathematical propositions are analytic and an extension of the principle 'Four is four'. How could the truth stating 'The diameter is always shorter than the circumference' be an analytic proposition? Are 'shortness' and 'circumference' included in the notion of 'diameter'? And is 'diameter' another expression for the statement, 'The diameter is a diameter'?
We conclude from this study that the rational doctrine is the only doctrine capable of solving the problem of the justification of knowledge, and setting up the criteria and primary principles of knowledge.
Still, it remains for us to study one point concerning the rational doctrine namely, that if the primary information is rational and necessary, then how is it possible to explain its absence in human beings at the beginning [of their existence], and their acquisition of it at a later date? In other words, if such information is essential for human beings, then it must be present whenever they exist. That is, it is impossible for them to be without it at any moment of their lives. If, on the other hand, it is not essential, then there must be an external cause for it - that cause being experience. But with this the rationalists do not agree.
In fact, when the rationalists assert that those principles arc necessary in the human mind, they mean by this that if the mind conceives the ideas that are linked together by means of those principles, then it infers the first principle, without need of an external cause.
Let us take (p. 88) the principle of non-contradiction as an example. This principle, which is an assent stating that the existence and non-existence of a thing cannot be simultaneous, is not available to human beings at the moment they begin to exist. This is because it depends on the conception of existence, non-existence and the simultaneity [of the two]. Without the conception of these objects, it is not possible to make the assent that existence and non-existence cannot be simultaneous. The assent of a human being to something he has no conception of is impossible. We had already learned in our attempt to analyze mental conceptions that all conceptions result and proceed from the senses, whether directly or indirectly. Thus, by means of the senses, human beings must acquire the group of conceptions on which the principle of non-contradiction depends, so that they will have the opportunity to judge and assent by means of it. Therefore, the fact that this principle appears later on in the human mind does not indicate that it is not necessary, and that it does not proceed from the innermost being of the human soul without requiring an external cause. Indeed, it is necessary and does proceed from the soul independently of experience. The specific conceptions are necessary conditions for its existence and for its proceeding from the soul. If you wish, compare the soul and the primary principles to fire and its burning [respectively]. As the burning of fire is an essential act of fire, yet does not exist except in light of certain conditions - that is, when fire meets a dry body; so also are the primary judgements necessary and essential acts of the soul when the necessary conceptions are complete.
If we choose to speak on a higher level, we would say that even if primary knowledge occurs to human beings gradually, this gradualness would not mean that it occurs due to external experience. For we have already shown that external experience cannot be the primary source of knowledge. Rather, this gradualness is in accordance with the substantial movement and development of the human soul. Such development and substantial integration is responsible for the increase in the soul's completion and awareness of the primary information and the fundamental principles - thus opening up the capacities and powers that lie latent in it. (p. 89)
This makes it clear that the objection to the rational doctrine as to why the primary information is not present with human beings at the moment of their birth depends on the non-acceptance of potential existence and the unconsciousness that is very clearly indicated by memory. Thus, the human soul itself includes this primary knowledge in potentiality. By the substantial movement, the existence of the soul increases in intensity, until those objects that are known potentially become known actually.
Marxism and Experience
The empirical doctrine presented above is applicable to two views concerning knowledge. The first is that which states that all knowledge is complete in the first stage - that is, the stage of sense perception and simple experience. The second is that which states that knowledge involves two steps: the empirical step and the mental step - that is, application and theory or the stage of experience and that of comprehension and inference. The starting point of knowledge is the senses and experience. The high degree of knowledge is the formation of a scientific comprehension and a theory that reflects the empirical reality in depth and with precision.
The second view is the one adopted by Marxism concerning the problem of knowledge. However, Marxism recognized that this view in its apparent form will lead it to the rational doctrine, since this view assumes a field or an area of human knowledge external to the limits of simple experience. Thus, it established it on the basis of the unity between theory and application and the impossibility of separating one from the other. With this, it retained the place of experience, the empirical doctrine, and the consideration of it as a general criterion of human knowledge.
Mao Tse-tung makes the following remark:
The first step in the process of acquiring knowledge is the immediate contact with the external environment - this being the stage of sense perception. The second step (p. 90) is the gathering, the arranging and the ordering of the information which we receive from the sense perception - this being the stage of notions, judgments and conclusions. By acquiring sufficient and complete information from sense perception (neither particular nor insufficient) and corresponding such information to the real situation (not false notions), then we may be able to form on the basis of such information a true notion and a sound logic. 
He also says this:
The continuous social application leads to the repetition of multiple occurrences in people's application of things which they perceive by the senses, and which create in them an impression. At this point, a sudden change in the form of a leap occurs during the process of acquiring knowledge. With this, notions are created. 
In this text, Marxism asserts that theory is inseparable from application namely, the unity of theory and application:
It is important, therefore, that we understand the meaning of the unity of theory and application. It asserts that he who neglects theory falls into the philosophy of practice, moving as a blind person moves and falters in the dark. As for him who neglects (p. 91) application, he falls into doctrinal stagnation, and turns into one who has nothing but a doctrine and empty rational demonstration. 
With this, Marxism confirmed its empirical position - namely, that sense experience is the criterion that must be applied to all knowledge and to every theory, and that there is no knowledge apart from experience, as Mao Tse-tung declared in the following:
The theory of knowledge in dialectical materialism gives application the first place. It views people's acquisition of knowledge as requiring no degree of separation from application. It also wages a war against all theories which [it considers] erroneous [for] denying the importance of application, or allowing the separation of knowledge from application. 
It seems that Marxism admits two stages of human knowledge, yet it does not wish to accept that some knowledge is separable from sense experience. This is the basic contradiction on which the theory of knowledge in dialectical materialism is based. That is, if the mind does not have some fixed knowledge, which is independent of sense experience, it will neither be able to postulate a theory in light of sense perception, nor to understand the empirical propositions. This is because the inference of a specific idea from the sensible phenomena in experience is possible for a human being only if he knows, at least, that such phenomena require by nature such an idea. Thus, he establishes the inference of his specific theory on this [knowledge].
To clarify this point, we must know that sense experience, as Marxism admits, (p. 92) reflects the phenomena of things, but does not reveal their substance and their internal laws that regulate and organize these phenomena. No matter how much we repeat the experience and reinstate the practical application, we will achieve at best only a new set of separable superficial phenomena. Clearly, such empirical knowledge that we acquire through sense experience does not in itself require the formation of a specific rational idea of the external thing. The reason is that such empirical knowledge, which is the first stage of knowledge, may be shared by many individuals; however, not all of them reach a unified theory and a single notion concerning the substance of a thing and its actual laws.
We learn from this that the first stage of knowledge is not sufficient by itself for the formation of a theory -that is, for moving a human being, whether naturally or dialectically, to the second stage of real knowledge. What thing, then, enables us to move from the first to the second stage?
This thing is our rational knowledge which is independent of sense experience, and on which the rational doctrine is based. Such knowledge makes it possible for us to present a number of theories and notions, and to notice the extent of harmony between the phenomena that are reflected in our experiences and sensations [on the one hand] and these theories and notions [on the other hand]. We eliminate every notion that does not agree with such phenomena, until, by virtue of the judgement of the primary rational knowledge, we attain a notion that is in harmony with sensible or empirical phenomena. Then we posit this notion as a theory that explains the substance of a thing and the laws that govern that thing.
If, from the very beginning, we isolate the independent rational knowledge from sense experience, then it becomes totally impossible to move from the stage of sense perception to that of theory and inference, and to be sure about the correctness of the theory and inference by returning to the application and the repetition of experience. (p. 93)
We conclude from this that the only explanation concerning the second stage of knowledge - that is, the stage of judgement and inference - is the assertion on which the rational doctrine is based: namely, that a number of the general laws of the world are known by human beings independently of sense experience. Such laws are exemplified by the principle of non-contradiction, the principle of causality, and the principle of harmony between cause and effect, as well as other similar general laws. When scientific experimentation presents human beings with the natural phenomena and reflects such phenomena in their sense perceptions, then human beings apply the general principles to these phenomena, and determine, in light of these principles, their scientific notion about the actuality and substance of a thing. This is to say that they seek to discover what lies behind empirical phenomena, and to delve into higher realities, as the application of the general principles both dictates and seeks. These realities, which are of a higher value, are added to their previous information. With this, they acquire a larger wealth (of information which they can employ] when they attempt to solve a new riddle of nature in another experimental field. We do not mean by this that application and scientific experimentation do not play an important role in human knowledge of nature and its laws. There is no doubt about their role in this. Rather, we only wish to assert that the elimination of all knowledge which is independent of experience and the rejection of rational knowledge in general makes it impossible to go beyond the first stage of knowledge, i.e. the stage of sense perception and experience.
Sense Experience and the Philosophical Edifice
This polarized contradiction between the rational doctrine and the empirical doctrine does not stop at the limits of the theory of knowledge. Rather, its dangerous influence extends to the whole philosophical edifice. This is because the fate of philosophy as a genuine edifice independent of the natural and the empirical sciences is, to a great extent, linked to the method of resolving this contradiction between the above-mentioned two doctrines. Thus, a discussion of the general criterion of human knowledge and the primary principles of such knowledge is something that would either justify the existence of philosophy, or rule (p. 94) that philosophy must withdraw and leave its task to the natural sciences.
The philosophical edifice has faced this dilemma or this test ever since the empirical method developed and invaded the scientific fields with efficiency and zeal. Here is what happened.
Before the empirical tendency prevailed, philosophy, at the dawn of its history, included almost all human knowledge arranged in general order. Thus, mathematics and the natural sciences were presented on a philosophical level, just as the metaphysical issues were presented. In its general and comprehensive sense, philosophy became responsible for discovering the general truths in all the fields of being and existence. In all those fields, philosophy used the syllogism as a tool for knowledge -the syllogism being the rational method of thinking, or the movement of thought from general to more particular propositions.
Philosophy remained in control of the human intellectual sphere, until experimentation began to push its way through, and to perform its role in many fields by moving from particulars to universals, and from subjects of experiments to more general and more comprehensive laws. Thus, philosophy found itself obliged to shrink and limit itself to its basic field, and to open the way for its competitor, science, to become active in the other fields. With this, the sciences separated from philosophy, and the specific tools and scope of each were determined. Thus, philosophy manipulates the syllogism as a rational tool of thought. Science, on the other hand, employs the empirical method and moves from particulars to higher laws. Similarly, every science treats a branch or a kind of existence proper to it and can be subject to experimentation. One investigates the phenomena and laws of science in light of the experiments that one carries out. Philosophy, on the other hand, treats existence in general, without limitation or restriction. It investigates its phenomena and principles that do not submit to direct experimentation. (p. 95)
Thus, while the natural scientist investigates the law that governs the expansion of corporeal particles by heat, and the mathematician investigates the mathematical proportion between the diameter of a circle and its circumference the philosopher investigates whether there is a first principle of existence from which the whole universe proceeded, the nature of the relation between the cause and effect, and whether it is possible for every cause to have (another] cause, [and so on) to infinity. He also investigates whether the human essence is purely material or a mixture of matter and spirit.
It is clear at first sight that it is possible to subject to experimentation the content of the issues raised by the scientist. Thus, it is possible for experimentation, for example, to provide evidence that the corporeal particles expand by heat, and that the diameter multiplied by 3.14 over 100 [ p X d] equals the circumference of the circle. But the direct nature of philosophical issues is the contrary of this. The first principle, the nature of the relation between the cause and effect, the infinite progression of causes, and the spiritual element in human beings are metaphysical matters to which sense experience does not extend, and which cannot be observed under the factory lights.
Thus, the duality between philosophy and science developed because of their disagreement on the tools and subjects of thought. This duality or this division of intellectual tasks between philosophy and science seemed proper and accepted by many rationalists who adopt the rational method of thinking, and who admit that there are primary, necessary principles of human knowledge. Naturally the defenders of the empirical doctrine, who accepted nothing but sense experience, and had no faith in the rational method of thinking, launched a strong attack against philosophy as a field independent of science. This is because they do not admit any knowledge that does not rest on experience. As long as the subjects of philosophy lie outside the sphere of experience and experimentation, there is no hope for philosophy's arriving at sound knowledge.
Therefore, according to the empirical doctrine, philosophy must (p. 96) abandon its task and admit modestly that the only field that human beings can study is the experimental field that the sciences have divided among themselves, leaving nothing for philosophy.
From this we learn that philosophy's lawful existence is linked to the theory of knowledge and to the faith in, or rejection of, the rational method of thinking that this theory asserts. On the basis of this, a number of modern schools of materialistic philosophy attacked the independent existence of philosophy which is established on the ground of the rational method of thinking. They also permitted the establishment of a philosophy that rests on the ground of the intellectual sum of all the sciences and empirical experiences, and that is not distinguished from science in method and subject. This scientific philosophy can be employed to uncover the relations and links among the sciences, and to postulate general scientific theories based on the outcome of experiments in all the scientific fields. Similarly, every science has its own philosophy which determines the methods of scientific investigation in that specific field. Foremost among these schools is positivist materialism and Marxist materialism.
The Positivist School and Philosophy
The seed of the positivist school in philosophy germinated during the nineteenth century, in which the empirical tendency prevailed. Thus, this school developed under the auspices of this empirical tendency. For this reason, positivist materialism launched a 'bitter attack through accusations against philosophy and its metaphysical subjects. But it was not satisfied with making the accusations against metaphysical philosophy that proponents of the empirical doctrine usually make against philosophy. It did not limit itself, for example, to the assertion that the philosophical propositions are useless for practical life and cannot be demonstrated by the scientific method. Rather, the positivists went on to assert that these are not propositions in the logical sense, in spite of their having the form (p. 97) of a proposition in their linguistic construction, because they have no meaning at all. They are empty phrases and nonsensical expressions, and as long as they are such, they cannot be the subject of any kind of investigation. For only comprehensible phrases, not empty expressions and nonsensical utterances, are worthy of investigation.
The philosophical propositions are empty phrases having no meaning by virtue of the criterion for comprehensible phrases laid down by the positivist school. It estimates that a proposition does not become a comprehensible phrase, and consequently a complete proposition in the logical sense, unless the concept of the world is different in the case of the truth of the proposition from what it is in the case of the falsity of that proposition. If you say, for example: 'The cold is intensified in winter,' you find that in the case of the truth of this phrase, there is a specific concept and proper sensible givens of the actual world; while in the case of its falsity, there is another concept and other givens of this world. Owing to this, we are able to describe the actual circumstances in which we know the truth or falsity of the phrase, as long as there is a difference in the actual world between the fact that the proposition is true and the fact that it is false. But take the following philosophical proposition: 'For everything, there is a substance in addition to its sensible givens. The apple, for example, has a substance which is the apple in itself, over and above what we perceive of the apple by sight, touch, and taste.' You will not find a difference in external reality between the fact that this proposition is true and the fact that it is false. This is evidenced by the fact that if you conceive of the apple as having a substance in addition to what you perceive of it by your senses, and then conceive it as not having such a substance, you will not see a difference between the two conceptions. The reason is that you will not find in either conception anything other than the sensible givens, such as color, odor and texture. But as long as we do not find in the conception that we have sketched for the case of truth anything that distinguishes it from the conception that we have sketched for the case of falsity, the above-mentioned philosophical phrase must be a meaningless discourse, since it does not provide any information about the world. The same is true of all philosophical propositions that treat metaphysical subjects. These are not comprehensible phrases, due to the fact that they do not meet the basic condition for the comprehensibility of phrases - this condition being the ability to describe (p. 98) the circumstances in which the truth or falsity of a proposition is known. That is why it is not appropriate to describe a philosophical proposition as true or false, because truth and falsity are attributes of comprehensible phrases, and the philosophical proposition has no meaning that would make it true or false.
We can now summarize the qualities that the positivist school attributes to philosophical propositions:
Let us take up the first quality - namely, that the philosophical proposition cannot be confirmed. This point repeats what the proponents of the empirical doctrine reiterate in general. These proponents believe that sense experience is the primary source and highest instrument of knowledge. But sense experience cannot exercise its function on the philosophical level, because the subjects of philosophy are metaphysical and [therefore], are not subject to any kind of scientific experience. If we rejected the empirical doctrine and demonstrated that at the heart of the human intellect there is prior knowledge on which the scientific edifice in the various fields of sense experience is based, we could reassure [others] about the human mind's potentialities and capacities to study the philosophical propositions, and to investigate them in light of this (p. 99) prior knowledge by the method of induction and the descent from the general to the particular.
Regarding the second quality - namely, that we cannot describe the conditions under which, if they obtained, the proposition would be true; otherwise, it would be false -it is still in need of some clarification. What are these actual conditions and sensible givens to which the truth of the proposition is linked? Further, does positivism consider it a condition of the proposition that its evidence must be a sensible given, as in the statement: 'The cold is intensified in winter, and rain falls in that season'? Or is it satisfied that the proposition has sensible givens, even though it may have them indirectly? If positivism rejects every proposition except if its evidence is a sensible given and an actual condition subject to sense experience, then positivism will not only eliminate philosophical propositions, but will also reject most scientific propositions that do not express a sensible given, but a law derived from the sensible givens, such as the law of gravity. For example, we perceive the fall of the pencil from the table to the ground, but we do not perceive the gravity of the ground. The pencil's fall is sensibly given and is linked to the scientific implication of the law of gravity. However, this law itself is not sensibly given directly. If positivism is satisfied with that which is sensibly given indirectly, then philosophical propositions have indirect sensible givens, exactly as a number of scientific propositions do; that is, there are sensible givens and actual conditions that are linked to the philosophical proposition. If such givens and conditions are available, the proposition is true; otherwise, it is false. Take, for example, the philosophical proposition that asserts the existence of a first cause of the world. Even if the content of this proposition has no direct sensible givens, still the philosopher can reach it by way of the sensible givens that cannot be explained rationally except by means of the first cause. This will be pointed out in future discussions in this book.
Positivism can say one thing regarding this point: the derivation of the rational content of a philosophical proposition from the sensible givens does not (p. 100) rest on empirical grounds, but on rational grounds. This means that rational knowledge determines the explication of the sensible givens by supposing a first principle, rather than that sense experience proves the impossibility of such givens without the first principle. Unless sense experience proves this [impossibility], such givens cannot be considered even as indirect givens of the philosophical proposition.
This assertion is nothing but another repetition of the empirical doctrine. If, as we learned earlier, the derivation of general scientific notions from the sensible givens depends on prior rational knowledge, then the philosophical proposition is not harmed if it is linked to its sensible givens by means of rational links, and in light of prior knowledge.
Until now, we have not found anything new in positivism other than the givens of the empirical doctrine and its notions concerning philosophical metaphysics. The third quality, however, appears to be something new. This is because there, positivism asserts that the philosophical proposition has no meaning whatsoever, and cannot even be considered a proposition. Rather, it is something that resembles a proposition.
We can say that this accusation is the strongest blow that the philosophical schools of the empirical doctrine direct against philosophy. Let us, therefore, discuss its content carefully. However, in order for us to be able to do so, we must know exactly what positivism intends by the term 'meaning' in the statement: 'The philosophical proposition has no meaning' -, even though this term can be explained in language dictionaries.
Professor Ayer,  a leading figure of modern logical positivism in England, responds by saying that, according to positivism, the term 'meaning' signifies the idea whose truth or falsity one can affirm within :he limits of sense experience. Because this is not possible in a philosophical proposition, such a proposition, therefore, is meaningless. (p. 101)
In light of this, the phrase, 'The philosophical proposition is meaningless', becomes exactly equivalent to the phrase, 'The content of the philosophical proposition is not subject to sense experience, because it is related to what is beyond nature'. With this, positivism would have asserted an indubitable and an indisputable truth - namely, that the subjects of philosophical metaphysics are not empirical. But it would not have offered anything new except a development of the term 'meaning', and a merging of sense experience with it. However, stripping the philosophical proposition of meaning in light of this development of the term does not contradict the admission that it has meaning in another use of the term, in which 'sense experience' is not merged with 'meaning'.
I do not know what Professor Ayer and other similar positivists would say about the propositions that are related to the sphere of nature, and whose truth or falsity a human being cannot assert by means of sense experience. If we say, for example, 'The other side of the moon which does not face the earth is full of mountains and valleys', we will not have - and we may not be given the opportunity in the future to have - the empirical capabilities for discovering the truth or falsity of this proposition, even though it is concerned with nature. Can we consider this proposition empty or meaningless, when all of us know that science often presents propositions of this kind for exploration, before it acquires a decisive sense experience concerning them? It continues to search for a light that it can shed on them, until at last it either finds it or fails to do so. What, then, is all this scientific effort for, if every proposition, whose truth or falsity is not evidenced by sense experience, is an empty and a nonsensical phrase?
In this respect, positivism attempts to make some revisions. It asserts that what is important is logical possibility and not actual possibility. Thus, every proposition is meaningful and worthy of discussion, if it is theoretically possible to achieve a sense experience that gives guidance concerning it, even if we do not actually have such an experience.
We see in this attempt that positivism has borrowed a metaphysical notion (p. 102) to complete the doctrinal structure it had established for the purpose of destroying metaphysics. This notion is the logical possibility, which it distinguished from the actual possibility. If this were not so, then what is the sensible given of the logical possibility? Positivism states that if a sense experience does not have real possibility, then what meaning will its logical possibility have, other than its metaphysical meaning that does not affect the picture of external reality, and in whose respect the sensible givens do not differ? Is it not the case that the positivist criterion for the comprehensibility of phrases has become, in the, last analysis, metaphysical, and, consequently, an incomprehensible phrase, according to positivism?
Let us leave aside Professor Ayer and take the word 'meaning', in its traditional sense - that is, without merging it with 'sense experience'. Can we now judge the philosophical proposition to be empty of meaning? The answer is indeed, No. After all, the meaning is the conception that the expression reflects in the mind. The philosophical proposition reflects conceptions of this sort in the minds of its proponents and opponents alike. As long as there is a conception that the philosophical proposition gives to our minds, then there is room for truth and falsity; consequently, there is a complete proposition worthy of the name [proposition] in the logical sense. If the conception that the philosophical proposition gives to our minds corresponds to an objective thing outside the limits of the mind and expression, the proposition is true. If not, then it is false. Truth and falsity and, hence, the logical mark of the proposition, are not given by sense experience so that we can say that a proposition which is not subject to sense experience cannot not be described by truth or falsity. Rather, they are two expressions in the form of affirmation or negation concerning the correspondence between the concept of a proposition in the mind and any fixed objective thing external to the mind and to the expression.
Marxism and Philosophy
The Marxist position regarding philosophy is essentially similar to the position held by positivism. Marxism completely rejects a higher philosophy which is imposed on the sciences, and which does not proceed (p. 103) from them. This is because Marxism is empirical in its outlook and method of thinking. Therefore, it is natural that it does not find room for metaphysics in its investigations. Due to this, it calls for a scientific philosophy -that is, dialectical materialism. It claims that this philosophy rests on the natural sciences and draws its strength from the scientific development in various fields. Here is a passage from Lenin: 
Dialectical materialism is no more in need of a philosophy higher than the other sciences. The only thing that remains of ancient philosophy is the theory and laws of the mind, i.e. formal and dialectical logic. 
Also, Roger Garaudy  makes the following statement:
To be exact, the task of the materialist theory of knowledge will be never to cut off philosophical thought from scientific thought or from historical practical activity. 
In spite of Marxism's insistence on the scientific character of its philosophy and its rejection of any kind of metaphysics, we find that the scientific limits of investigation do not restrict its philosophy. The reason is that the philosophy, which issues from the scientific experience, must exercise its function in the scientific field, and not step beyond it to other fields. According to Marxism, even if the proper field of a scientific philosophy, such as that of Marxism, is broader than any other field specified for any science, since it is guided by the various sciences; still, it is not at all permissible that it be broader than all the scientific fields put together - that is, than the general scientific field which is the nature that can be subjugated to sense experience or to organized empirical observation. (p. 104) It is not the job of scientific philosophy to treat metaphysical issues in its discussions, and to judge them either affirmatively or negatively. The reason is that its scientific resources do not provide it with any [information] concerning such issues. Thus, it is not the prerogative of scientific philosophy to judge, whether affirmatively or negatively, the following philosophical proposition, 'There is a first metaphysical principle of the world', for the content of such a proposition lies outside the realm of sense experience.
In spite of this we find that Marxism takes up this kind of proposition, and responds to it by negation. This makes it rebel against the limits of scientific philosophy and move to a metaphysical discussion. This is so, because negation concerning metaphysical issues is the same as affirmation; that is, both belong to metaphysical philosophy. With this, contradiction appears between the limits at which Marxism must stop in its philosophical investigation, since it is characterized by having a scientific philosophy and by its advance in investigation to broader limits.
After Marxism linked its philosophy to science, asserting that the philosophical outcome must be in agreement with the natural sciences and the participation of philosophy in the development and integration of science, as a result of the rise [in emphasis on] sense experience and its profundity with the passage of time, it was natural for it to reject every philosophical preoccupation [with anything] beyond science.
This resulted from the mistake of Marxism in the theory of knowledge and its faith in sense experience alone. On the contrary, in light of the rational doctrine and the faith in prior knowledge, philosophy rests on fixed fundamental principles. These principles are pieces of a prior rational knowledge that is absolutely fixed and independent of sense experience. Due to this, it is not necessary that the philosophical content continuously change as a result of empirical discoveries.
We do not intend by this to break the link between philosophy and science. The link between them is firm indeed. At times, science presents philosophy with particular facts (p. 105) in order that philosophy may apply its principles to such facts; so that, it could introduce new philosophical conclusions.  Similarly, philosophy assists the empirical method in science by means of rational principles and rules which the scientist employs for the purpose of moving from direct experience to a general scientific law. 
Therefore, the link between philosophy and science is strong.  Yet in spite of this, philosophy (p. 106) may at times not need any sense experience. Rather, it draws the philosophical theory from prior rational knowledge.  Because of this we said that it is not necessary for the philosophical content to change continuously as a result of empirical experience. Nor is it necessary for the whole of philosophy to accompany the procession of science in its gradual march.
Author's Notes to Part One, Chapter One
 Some of the empiricist philosophers, such as John Stuart Mill [1806-73], have held a specific theory of assent in which they attempt to explain assent as two associated conceptions. Thus, assent [according to them], can be attributed to the laws of the association of ideas. The content of the soul is nothing other than the conception of a subject and the conception of a predicate.
However, the truth is that the association of ideas is completely different from the nature of assent, for it can be attained in many areas where there is no assent. For example, the conception in our minds of historical figures to whom myths attribute various kinds of heroism is linked to the conception of those heroic acts. The [two] conceptions are then associated; still, we may not assent to any of those myths.
Assent, therefore, is a new element distinguished from pure conception. The lack of distinction between conception and assent in a number of modern philosophical studies has led to a number of errors. It also made a number of philosophers investigate the issue of the justification of knowledge and perception without distinguishing between conception and assent. You will know that the Islamic theory [of knowledge] distinguishes between the two and explains the issue in each of them by a specific method.
 Put in more detail, the multiplicity of effects shows one of four things: (1) a multiplicity of agents; (2) a multiplicity of recipients; (3) a logical order among the effects themselves; or (4) a multiplicity of conditions. Regarding our issue, there is no doubt that the conceptions, whose source is the subject of our concern, are many and varied in kind, even though there is no multiplicity of agents or of recipients. This is because the agent and the recipient of the conceptions is the soul, and the soul is simple. Also, there is no order among the conceptions. For this reason it remains that we must adopt the last explanation, i.e., that the multiplicity of conceptions depends on external conditions - these conditions being the different kinds of sense perceptions.
 Al-Maddiyya wal-Mithaliyya fi al-Falsafa, p. 75.
 Ibid., pp. 71-2.
 Hawl at-Tatbiq, p. 11
 Ibid., p. 14.
 The attempt made by Dr Zaki Najib Mahimud is strange indeed - namely, to ground the previously mentioned objection in syllogistic reasoning, as in our saying: 'All human beings are mortal; Muhammad is a human being; therefore, Muhammad is mortal.' He says that you may say, 'But when I generalize in the first premise, I do not intend human beings one by one, because considering them in this way is impossible. Rather, I intend the [human] species in general.'
If this is what you think, then how can you apply the judgement specifically to Muhammad, since Muhammad is not the species in general? Rather, he is a specific determined individual. Thus, the judgement concerning him which you apply to the species in general is in truth an invalid syllogism (al-Mantiq al-Wad'iyy, p. 250).
This is a strange confusion between first intentions and second intentions (as logicians are accustomed to calling them). A judgement concerning the species in general means one of two things. The first is that the judgement concerning a human being is characterized by what is general or by the species of that human being. It is clear that such a judgement cannot be specifically applied to Muhammad, because Muhammad does not have the quality of generality or of being a species. The second is that the judgement concerning a human being himself is not relative. That is, it does not pertain specifically to him. This kind of judgement can be applied to Muhammad, because Muhammad is a human being. The middle term has the same meaning that is repeated in both the minor and the major premises. Thus, the syllogism yields a conclusion.
 Hawl at-Tatbiq, p. 14.
 Ibid., p. 6.
 Al-Maddiyya wal-Mithaliyya fi al-Falsafa, p. 114.
 Hawl at-Tatbiq, p. 4.
 Lenin, Marx, Engels and Marxism, p. 24
 Ma Hiya al-Madda, p. 46.
 This is exemplified in the fact that the natural sciences demonstrate the possibility of transferring simple elements into simpler elements. This is a scientific truth which philosophy treats as a subject of its investigation, and to which it applies the rational law that states that an essential quality is never absent from the thing. From this, we conclude that the form of the simple element, such as the form of gold, is not essential for the matter of gold; otherwise, it would be inseparable from it. Rather, it is an accidental quality. But philosophy goes further than this. It applies the law that states that for every accidental quality there is an external cause. Thus, it reaches the following conclusion: 'In order for matter to be gold, brass, or something else, it is in need of an external cause.' This is a philosophical conclusion resting on the general rules to which the rational method led in its application to the raw material that science presents to philosophy.
 Examples of this were offered earlier. We saw how the scientific theory stating that motion is the cause or substance of heat requires a number of prior rational principles.
 So that it would be possible to say in light of what we have determined - contrary to the general tendency we have followed in the book - that there is no dividing line between the laws of philosophy and the laws of science. Such a dividing line is exemplified in the statement: 'Every law resting on rational grounds is philosophical, and every law resting on empirical grounds is scientific.' For we knew with clarity that the rational grounds and sense experience merge in a number of philosophical and scientific propositions. The scientific law is not the product of sense experience alone. Rather, it is the product of the application of the rational principles to the content of scientific experience. Nor can the philosophical law always dispense with sense experience. Rather, scientific experience may be a subject of the philosophical investigation or a minor premise in the syllogism, as Aristotelian logic teaches. The difference between philosophy and science is that philosophy may not need an empirical minor premise, nor does it need to borrow raw material from sense experience, as we will soon point out. Science, on the other hand, requires organized empirical experience for all its laws.
 An example of this is the law of finitude, which states that causes do not ascend infinitely. When philosophy admits this law, it does not find itself in need of any scientific experience. Rather, it draws it from primary rational principles, even if indirectly.
Translator's Notes to Part One, Chapter One
 At-tasawwur (form, grasping, imaging, apprehension, conception).
 At-tasdiq (belief, judgement, assent).
 That is, knowledge with no judgement. This is to say that conception is the grasping of an object without a judgement.
 Compare this with Ibn Sina's notion of conception and assent in Ibn Sina, Remarks and Admonitions, Part One, Logic, translated by Shams C. Inati, Toronto, Ontario, Canada, Pontifical Institute of Mediaeval Studies, 1984, pp. 5-6 and 49-50.
 Text: ka-tasawwurina, which we have chosen to translate here as 'grasping', rather than as 'conception', as we are doing for the most part in this work. This is because it would not be helpful to say that conception is exemplified in conception.
 Text: ka-tasdiqina, which we have chosen to translate here as judgement', rather than as 'assent' in order to explain better what is meant by 'assent'.
 For the theory of knowledge as recollection, see Plato, Meno 81 c, 85d, 98a; Philebus 84c; Theaetetus 198d.
 The Platonic archetypes are also referred to as 'forms' or'ideas'. They are models of things. They are immaterial, fixed, primary realities, separate, indivisible, unchangeable and incorruptible.
 Rene Descartes, French philosopher (1596-1650). Descartes reminds us of al-Ghazali who, in search of certain knowledge, began by doubting everything. But if he doubts everything, he must exist in order to doubt; for doubting is a form of thinking, and to think is to exist. 'I think, therefore, I exist' is the first proposition of which he becomes certain. Later, he reaches the knowledge that God exists from the certainty of his knowledge of his self. But by definition God is good. Therefore, He cannot be a deceiver. Hence, the ideas about the existence of an external world that He causes in us must be true. Also a known view of Descartes is that concerning the duality of soul and body. Because the soul is independent of the body, it can survive without it after their separation. Hence, immortality is possible. His main writings are Discourse on Method, The Meditations, Principles of Philosophy, The Passions of the Soul and Ruler for the Direction of the Mind.
 Immanuel Kant, German philosopher (1724-1804). Kant's position was a synthesis of the rationalism and empiricism of the day. In his masterpiece, Critique of Pure Reason, 'pure' here is used in the sense of 'a priori' - i.e., that which can be known apart from any sense experience, Kant critically examined the nature of reason. He concluded that there are no innate ideas - i.e., ideas known prior to any sense experience. However, this did not lead him to draw the conclusion that the empiricists drew, namely that all knowledge is the product of sense experience. Rather, he held that our faculties of sensibility and understanding have formal structures that mold our experience. This means that certain qualities that we perceive in objects are imparted to them from the natural structures of our sensibility and understanding. Sensibility presents us with objects bare of any regularity. Understanding then takes over and organizes our sense experience as experience of the natural world. Kant is very clear. The regularity of nature is a contribution of our own understanding. He believed that the understanding has twelve concepts or 'categories' that are not derived from sense experience. Apart from sense experience, these concepts are empty, and without them sense experience is disorderly and incomprehensible. The applicability of these concepts is limited to the sphere of sense experience. The conclusion Kant drew is that speculative metaphysics is futile, since it attempts to apply these concepts to objects beyond the empirical realm. However, such an inappropriate attempt is a natural inclination of the human mind.
Kant wrote two other critiques, Critique of Practical Reason and Critique of Judgement, as well as some other important works, such as Groundwork of the Metaphysics of Morals. But there is no room in this brief account to touch upon Kant's ideas in such works. We have limited ourselves to a quick presentation of his major views in the first critique, not only because they constitute the main pillars of his philosophical system, but also because they are the most relevant to Our Philosophy.
 Kant's twelve categories are: (1) quantity, under which there are (a) unity, (b) plurality and (c) totality; (2) quality, under which there are (d) reality, (e) negation and (f) limitation; (3) relation, under which there are (g) inherence and subsistence (substance and accident), (h) causality and dependence (cause and effect) and (i) community reciprocity between agent and patient; (4) modality, under which there are: (j) possibility-impossibility, (k) existence - non-existence and (l) necessity contingency (Critique of Pure Reason, Analytic of Concepts, ch. 1, B95 and 106, A7 0 and 80).
 John Locke, English philosopher (1632-1704). He denied the existence of innate ideas - i.e., ideas at birth. According to him, the source of all our ideas is experience, which consists of sensation and reflection. His best known philosophical work is Essay concerning Human Understanding (1690).
 George Berkeley, Irish philosopher (1685-1753). According to Berkeley, what Locke calls primary or objective qualities, such as distance, size and situation, exist only in the mind. To exist is either to be present to a mind - i.e., to be an idea, or to be a mind. His main writings are: A New Theory of Vision, Treatise concerning the Principles of Human Knowledge and Three Dialogues between Hylas and Philonous.
 David Hume, Scottish philosopher (1711-76). The central theme of his philosophy is this. Experience consists of impressions and ideas. The former are more lively than, and the source of, the latter. There are certain principles that guide our association of ideas. These are resemblance, contiguity and cause and effect. Experience produces in us custom, which is responsible for linking two successive events in a causal manner. He makes an important distinction between matters of fact and relations of ideas. Only the latter involve necessity. His main writings are: Treatise on Human Nature, Enquiry concerning Human Understanding, Enquiry concerning the Principles of Morals, History of England and Dialogues concerning Natural Religion.
 Such as one. But if there is one simple innate conception in the soul, the question arises as to how a multiplicity of conceptions could arise from this one. If, on the other hand, this limited number of innate conceptions is at most two, then this is a multiplicity.
 Al-Qur'an XVI, 78.
 Georges Politzer, French Communist (1908-42). He was born in Hungary, but at seventeen, left his native country for France. From then on, he became one of the most patriotic of Frenchmen. He was a member of the French Communist Party, and made many contributions to the paper of this party, L'Humanite. In 1940, he worked through his party to urge the people to defend Paris against the Germans. In 1941, he wrote and circulated a pamphlet of 45 pages which he called Revolution and Counterrevolution in the Twentieth Century. In 1942, he was imprisoned together with 140 Communists. He was executed the same year. His main work is Elementary Principles of Philosophy.
 Mao Tse-tung (1895-1976). He was born in central China. At six years old, he started working in the fields with his father, who was a farmer. When he was eight, he attended the local primary school until he was thirteen. After some further education in his own province, he joined the Communist Party in Peking. He led the struggle against the Kuomintang under Chiang Kai-shek. On October 1, 1949, he was made the first chairman of the People's Republic of China. He held this position until 1959.
 This is the passage that the author has in mind: '. . . but there is nothing in a number of instances, different from every single instance which is supposed to be exactly similar, except only that after a repetition of similar instances the mind is carried by habit, upon the appearance of one event, to expect its usual attendant and to believe that it will exist. This connexion, therefore, which we feel in the mind, this customary transition of the imagination from one object to its usual attendant, is the sentiment or impression from which we form the idea of power or necessary connexion. Nothing farther is in the case. Contemplate the subject on all sides; you will never find any other origin of that idea. This is the sole difference between one instance, from which we can never receive the idea of connexion, and a number of similar instances, by which it is suggested. The first time a man saw the communication of motion by impulse, as by the shock of two billiard-balls, he could not pronounce that the one event was connected, but only that it was conjoined with the other. After he has observed several instances of this nature, he then pronounces them to be connected. What alteration has given rise to this new idea of connexion? Nothing but that he now feels these events to be connected in his imagination, and can readily foretell the existence of the one from the appearance of the other' (The Enquiry concerning Human Understanding, VII, Edition of 1772, pp. 88-89).
 i.e., the notions of cause and effect, substance and accident, possibility and necessity, unity and multiplicity, existence and non-existence (see p. 66 of the original text).
 Text: wa-lidha (because of this).
 Induction is probable inference.
 A syllogism is a form of reasoning in which two propositions necessarily lead to a third.
 There are four figures of the moods of the categorical syllogism according to the position of the middle term in the premises. When the middle term is subject in the major premise and predicate in the minor premise, we get the first figure. When it is predicate in both premises, we get the second figure. When it is subject in both premises, we get the third figure. And when it is predicate in the major premise and subject in the minor premise, we get the fourth figure.
 Each of the two statements which together yield a conclusion is called 'premise' (premiss).
 That is, while experience can show us that a thing does not exist, it cannot show us that it is not possible for that thing to exist.
 These are examples of non-existent, yet possible things.
 These are examples of non-existent and impossible things.
 Alfred Ayer, English philosopher (1910-). He is a logical empiricist. He holds that genuine statements are either factual or analytic. The criterion for the significance of the former kind of statements is their verifiability. However, he does not go as far as the logical positivists in asserting that by verifiability is meant the conclusive establishment of a factual statement in experience, but only that such a statement be rendered probable by experience. His main writings are: Language, Truth and Logic, The Foundations of Empirical Knowledge, Philosophical Essays and Philosophy and Language.
 Vladimir Ilyich Ulyanov Lenin, founder of the Soviet Union (1870-1924). He was exiled from Russia 1905-17 as a result of the leading role he played in the revolution of 1905. From 1918 to 1924, he was the head of state and leading Marxist theoretician. His best-known works are Materialism and Empiro-criticism, and Imperialism, Final Stage of Capitalism.
 Roger Garaudy, Professor of Philosophy at Poitiers University and member of the Politburo of the French Communist Party (19091. In 1965, he spoke at a number of American universities, including Harvard, St Louis and Temple. His best known work is: La Liberte en Sursis.
Introduction - Islamic Philosophy Home - Table of Contents - Chapter 2