4. If we had to ascertain the nature of body and the place it holds in the universe, surely we should take some sample of body, say stone, and examine into what constituents it may be divided. There would be what we think of as the substrate of stone, its quantity- in this case, a magnitude; its quality- for example, the colour of stone. As with stone, so with every other body: we should see that in this thing, body, there are three distinguishable characteristics- the pseudo-substance, the quantity, the quality- though they all make one and are only logically trisected, the three being found to constitute the unit thing, body. If motion were equally inherent in its constitution, we should include this as well, and the four would form a unity, the single body depending upon them all for its unity and characteristic nature.
The same method must be applied in examining the Intellectual Substance and the genera and first-principles of the Intellectual sphere.
But we must begin by subtracting what is peculiar to body, its coming-to-be, its sensible nature, its magnitude- that is to say, the characteristics which produce isolation and mutual separation. It is an Intellectual Being we have to consider, an Authentic Existent, possessed of a unity surpassing that of any sensible thing.
Now the wonder comes how a unity of this type can be many as well as one. In the case of body it was easy to concede unity-with-plurality; the one body is divisible to infinity; its colour is a different thing from its shape, since in fact they are separated. But if we take Soul, single, continuous, without extension, of the highest simplicity- as the first effort of the mind makes manifest- how can we expect to find multiplicity here too? We believed that the division of the living being into body and soul was final: body indeed was manifold, composite, diversified; but in soul we imagined we had found a simplex, and boldly made a halt, supposing that we had come to the limit of our course.
Let us examine this soul, presented to us from the Intellectual realm as body from the Sensible. How is its unity a plurality? How is its plurality a unity? Clearly its unity is not that of a composite formed from diverse elements, but that of a single nature comprising a plurality.
This problem attacked and solved, the truth about the genera comprised in Being will thereby, as we asserted, be elucidated also.