He even transmitted the book of Logic with his own chain of transmission back to Mattā the Translator, the man who rendered it into Arabic; yet despite this he conceded the very point we have just made, as has been explained in detail elsewhere.

Let us, for the sake of argument, grant that those things do exist outside the mind. One might then learn that being is divided into five kinds of substance and that accident is divided into nine species—though some of them have never produced any proof for the number nine. They have even composed a mnemonic couplet for it:

Zayd, the tall, dark son of Mālik,
Was yesterday reclining in his house;
A sword in his hand—he unsheathed and brandished it:
Behold, these are ten categories in all.

In these two lines he mentions substance, quantity, quality, relation, where, when, position, possession, acting, and being acted upon.

Because no decisive proof confines the highest genera to nine, some reduced them to five, while others confined them to three: quantity, quality, and relation.

The point, however, is this: even if one masters this classification—and in their view the more universal a notion is, the more intelligible it becomes and the firmer the demonstration for it—still, a proof that must always be accepted can rest only on what is immutable. Yet these accidents, according to them, cannot subsist in the Necessary Existent, nor even in the separate intellects, save for a few of them—and even about those they disagree. Thus the alleged perfection is reduced to the mere conception of an absolute existence that has no reality outside the mind, like imagining an absolute essence, an absolute thing, or an absolute reality.

What perfection can the soul gain from nothing more than conceiving such general, universal notions when it has not grasped the concrete, particular realities of existing things? And what knowledge of the Lord of the worlds is to be found in this, when souls are perfected only by