Little Question Four of Principal Question One
How many are the causes from which acuity of understanding toward diverse sciences arises
It is asked how many accidental causes there are from which acuity of understanding and an inclination toward diverse sciences arise.
To this it is answered that there are five.
First, this can arise from the passions toward which a human being is disposed and inclined by a natural complexion. For one impassioned toward the vice of avarice is more inclined toward lucrative sciences and labors more fervently in them than in other sciences. The same applies to those impassioned toward other vices or virtues.
Second, it can occur because the completion or constitution of one human being, from whatever source, is more conformable or proportioned to the objects or things and their dispositions which the said science considers than is the constitution of another human being. Thus that science or art is more delightful to him.
Third, it can occur from the fact that sometimes in one human being the imaginative power excels, in another the discursive power, in another the judicative power, and in another the memorative power. And thus, according to this, one human being is more capable in one science than in another.
Fourth, this can occur from the disposition of the inferior root. For we see that the sons of painters are for the most part more apt for painting because of a disposition contracted from their parents.
Fifth, it can occur from frequent meditation upon, or presentation of, such things. For one who from youth saw painting being done, or took pleasure in seeing pictures, is more inclined toward painting than toward another art.
This was also the cause why sheep of varied color were born to Jacob: namely, from the frequent inspection and imagination of the sheep drinking the water beneath which were rods of varied colors. But on this account do not refer the matter entirely to nature, but to divine disposition, in Genesis 30.
Therefore, diversity of understandings does not arise from some special power impressed at birth, nor must the variety of complexions of human bodies and of other various natural conditions always be sought from the heaven, but from the other five modes just recounted.
These things are from Albert and Henry.
Addition to Little Question Four
Why some persons possess a subtler understanding while others possess a grosser one is, according to astrologers and especially Albumasar, because at the birth of some persons Mercury is in the house or exaltation of the Sun. Hence those who are born in this manner are endowed with understanding; but when Mercury is in the house of the Moon, grosser persons are born.
Indeed, know, according to Ptolemy in proposition 70, that those at whose birth the Moon does not aspect Mercury are insane, while those for whom the Moon aspects Mercury are wise because the Moon pours in the natural powers, while Mercury pours in the rational powers. Hence, when the natural powers by which the body is governed have regard to reason, that person is born wise; but when they do not have regard to it, that person is born insane.
And when Mercury is retrograde, the person being born is rendered dull in mind and forgetful; but when Mercury is direct, he is rendered swift in understanding. The reason is that stars which are not impeded perform their natural operations, but the opposite occurs if they are impeded.
From these causes it frequently happens that astrologers prognosticate true things concerning the characters of human beings. It is not that these things necessarily occur in this manner if a human being wills, through the will, to follow the law of reason rather than the senses; rather, it is because he is prone to follow the sensitive appetite, upon which the stars make an impression.
But take note that, because of the influences of the stars, we call one person intelligent and another obtuse with respect to the senses, but not with respect to the soul, which is in no manner subject to those influences.