AVICENNA 30

...because of the resistance of equality, action and passion meaning the mutual influence and change that occur when two things interact would not occur; and if this were possible, then two contraries would exist in the same subject. And it is clear that Avicenna exemplified the second division above by using the color ash-gray, which, when made artificially in the manner described above, can be granted as possible; nor does it follow from this that two contraries are in the same subject, as has been declared. Avicenna used this color to exemplify the aforementioned second division to make it clear, not to grant its existence in a natural mixture, because that is impossible, as was declared above. However, the third division is possible both in artificial things—as was said regarding a sculpture that occurs externally to a mixture of clay—and in natural things, as will be declared below.

TRULY it is not from the first division; that is, it is true that the soul is not a form belonging to the first division. AND IF NOT—that is, if the soul that arrives in a composite made of contrary forms were from the first division, namely a form that inclines toward the form of the simple elements—then it would be heat, or cold, etc. That is, the soul would be either the form of fire (which results in heat), or the form of water (which results in cold), or the form of air (which results in moisture), or the form of earth (which results in dryness). In these qualities, whichever one it might be, there occurs some reduction or remission a weakening or softening of a quality's intensity when they exist in a mixture. Therefore, if the soul, which arrives in a composite made of contrary forms, were to incline toward any of the simple forms—that is, to any form or quality of the elements composing the mixture—then the soul would possess the heat, cold, moisture, or dryness proper to the form toward which it inclines.

And just as heat, cold, and the other qualities of the elements are the instruments by which substantial forms the fundamental essence that makes a thing what it is, rather than just its accidental properties like size or color act—for the form of fire acts through heat, which is its instrument—similarly, if the soul inclined toward the form of fire or air, etc., then the soul would use one of these qualities as its own instrument in the operations that proceed from the soul itself. Since, therefore, any of the aforementioned qualities are diminished and refracted broken down or weakened by their opposite quality in a mixture, as is evident, how could any of these powers—namely the qualities of the elements—be disposed so that the operations of the soul could proceed from that very quality or qualitative power as an instrument? For such a quality in a composite is weakened and diminished; and at the time when the aforementioned qualitative power of the elements possessed its full complement, its perfection, and its perfect, undiminished power, it was not disposed to perform the operations we see proceeding from the soul.

Therefore, the sense of the preceding text is this: if the soul were to incline toward any substantial form of the elements, then it would possess heat or cold, etc., within itself. And it would use heat or cold, etc., in its operations as an instrument. And it is clear that any of these qualities...