21. The person who has gained the habit of a particular
craft is rarely able afterwards to master another.
A 101 tailor, for instance, who has acquired the habit of tailoring and knows it well and has that habit firmly rooted in his soul, will not afterwards master the habit of carpentry or construction, unless the first habit was not yet firmly established and its coloring not yet firmly rooted.
The reason for this is that habits are qualities and colors of the soul. They do not come all at once. A person who is still in his natural state has (an) easier (time) acquiring certain habits and is better prepared to gain them. When the soul has been colored by a habit, it is no longer in its natural state, and it is less prepared (to master another habit), because it has taken on a certain coloring from that habit. As a result, it is less disposed to accept (another) habit.
This is clear and attested by (the facts of) existence. One rarely finds a craftsman who, knowing his craft well, afterwards acquires a good knowledge of another craft and masters both equally well. This extends even to scholars whose habit has to do with thinking. (The scholar) who has acquired the habit of one particular science and masters it completely-will rarely achieve the same mastery of the habit of another science, and if he were to study (another science), he would, except under very rare circumstances, be deficient in it. The reason lies in the significance attaching, as we have mentioned, to preparedness and the fact that he becomes colored by the color that the soul receives from the habit it acquires.
And God knows better.