A maverick philosopher, respected medical authority, and seemingly somewhat tempestuous individual, Abu 'l-Barakat al-Baghdadi produced one voluminous work (the Kitab al-mu'tabar) in which the philosophical views current in his day - principally associated with the name of Ibn Sina - were subjected to a penetrating analysis, and many interesting alternatives suggested. His most provocative ideas concern self-awareness, the physics of motion and the idea of time.
Hibat Allah 'Ali ibn Malka Abu 'l-Barakat al-Baghdadi was an idiosyncratic, highly original philosopher who flourished in the first half of the twelfth century. Precise biographical information is unavailable. We know that he was born into a Jewish family (his Hebrew name was Nathanel) and, as a Jew, was refused entry to the lectures of Abu 'l-Hasan ibn Hibat Allah, a famous physician. Other slights, real or imagined, that he suffered on account of his faith seem to have contributed to his decision, very late in life, to convert to Islam. The appellation awhad al-zaman, 'the singular [personage] of his time', probably reflects his medical rather than philosophical achievements. His formal teaching seems to have been limited to medicine, in which he had a number of students. Ibn Khalliqan's biographical dictionary describes him as 'very presumptuous', his hauteur being revealed in his many disputes with the humbler physician Ibn al-Talmidh, which display the 'jealousy and rivalry that typically prevail between men who are eminent in the same profession'. His involvement in philosophy seems to have been informal (even by the standards of the time) and tentative. He had one notable disciple in the polymath Fakhr al-Din Al-Razi.
Al-Baghdadi's mature views are found in his comprehensive Kitab al-mu'tabar, the title of which should be translated, according to Shlomo Pines (1979), 'the book of what has been established by personal reflection'. Al-Baghdadi characteristically begins his investigations with a pellucid statement of each problem he considers. He then surveys earlier opinions in detail, rarely naming his sources. He takes great pains to ferret out the reasoning underlying each claim, following closely the development of the theory, the objections raised against it and the adjustments made by its proponents. Each issue is approached freely and independently, without much reliance on any over-arching methodological or philosophical commitments. The interplay between words and concepts is given particular attention. For example, al-Baghdadi developed his strikingly innovative theory of time after reaching the conclusion that the word 'time' as used in everyday speech stands for a very fundamental concept, the true nature of which has been obscured by scholastic analysis. Again, he lambasts aspects of the sulphur-mercury theory of metals as 'words that denote unreal fancies'.
Perhaps most interesting among al-Baghdadi's achievements is his reappraisal of the idea of time (Pines 1979). Dissatisfied with the regnant approach, which treated time as an accident of the cosmos, al-Baghdadi drew the conclusion that time is an entity whose conception (ma'qul al-zaman) is a priori and almost as general as that of being, encompassing the sensible and the non-sensible, that which moves and that which is at rest. Our idea of time results not from abstraction, stripping accidents from perceived objects, but from a mental representation based on an innate idea. Al-Baghdadi stops short of offering a precise definition of time, stating only that 'were it to be said that time is the measure of being (miqdar al-wujud), that would be better than saying [as Aristotle does] that it is the measure of motion'. His reclassification of time as a subject for metaphysics rather than for physics represents a major conceptual shift, not a mere formalistic correction. It also breaks the traditional linkage between time and space. Concerning space, al-Baghdadi held unconventional views as well, but he did not remove its investigation from the domain of physics (see Space; Time).
Al-Baghdadi's most significant departure in psychology concerns human self-awareness. Ibn Sina had raised the issue of our consciousness of our own psychic activities, but he had not fully pursued the implications for Aristotelian psychology of his approach. Al-Baghdadi took the matter much further, dispensing with the traditional psycholgical faculties and pressing his investigations in the direction of what we would call the unconscious.
Al-Baghdadi had many new ideas concerning the physics of motion. He seems to have adumbrated the notion of acceleration as an increase in the velocity of a moving body attributable to the application to it of a constant force. He also seems to suggest that motion is relative, that is, that there is motion only if the relative positions of the bodies in question change. These ideas are highlighted here because of their resemblance to modern thoughts on the same subjects. The Kitab al-mu'tabar contains many other, no less innovative ideas that have no modern counterpart; for example, the claim that each type of body has a characteristic velocity that reaches its maximum when its motion encounters no resistance. Although al-Mu'tabar is not a systematic work, comprising instead notes on various subjects that al-Baghdadi wrote for himself over the years, Pines showed that the paramountcy of a priori knowledge underlies many of the work's criticisms and innovations.
The impact of al-Mu'tabar on Islamic thought seems to have been limited to the Ishraqi (illuminationist) tradition, broadly defined (see Illuminationist philosophy). Indeed, the work's tripartite structure (logic, physics, metaphysics), the pride of place given to a priori knowledge, and the consequent primacy given to the author's own speculations, are the distinguishing features of Ibn Sina's Isharat wa-'l-tanbihat, the earliest prototype of the genre, and of al-Suhrawardi's al-Talwihat, its most important representative. However, the spiritual tone of the latter two books is far less prominent in al-Baghdadi's work, although perhaps not entirely absent. As Pines showed, the Ibn Sina of al-Shifa' (Healing) is the target of many of al-Baghdadi's criticisms, strictures often pursued in Fakhr al-Din al-Razi's commentary on al-Isharat, and answered in Nasir al-Din al-Tusi's glosses to the same work. Al-Tusi usually refers to 'al-Baghdadi and the other later [philosophers],' giving the impression that al-Baghdadi was the outstanding representative, or even founder, of a whole school of thinkers who challenged some of Ibn Sina's views. Al-Suhrawardi's al-Talwihat refers to al-Baghdadi obliquely as 'one of the Jewish philosophers'. The target of that reference is made clear by Ibn Kammna, whose commentary on al-Talwihat cites al-Baghdadi several times. Al-Baghdadi's views were known to al-Shahrazuri, and he is mentioned some half-dozen times in Sadr al-Din al-Shirazi's al-Asfar al-arba'a.
Despite his conversion to Islam, al-Baghdadi's works continued to be studied at the yeshivah of Baghdad, then the centre of Jewish conservatism, into the thirteenth century. Al-Baghdadi's commentary to the Book of Ecclesiastes continued to be copied at the same yeshivah, with full acknowledgement of its authorship. Shmu'el ben Eli, head of the yeshivah and archrival of Moses Maimonides, cites the Mu'tabar in support of his contention that even 'the philosophers' are forced to admit the possibility of bodily resurrection. Ben Eli does not reveal his source; it appears to have been Maimonides' disciple, Yosef ben Yehudah, who tracked down the reference.
Ibn Khalliqan reports that al-Baghdadi had a high reputation in the field of medicine, and al-Suhrawardi refers to him as 'a physician who sought to do philosophy'. He attended some of the Seljuq sultans and their families and is reported to have cured himself of leprosy, in the process causing himself a period of blindness. Ibn Abi Usaybi'a's biographical compendium relates some anecdotes and sayings and lists several of al-Baghdadi's medical works. However, few if any of these survive, and none have been studied. Al-Baghdadi also wrote a short treatise 'On the Reason that the Stars appear at Night but are invisible during the Day', and another small tract on the intellect.
See also: Ibn Sina; Illuminationist philosophyY. TZVI LANGERMANN