relatives reciprocate. Besides, if he who explains a thing not per se, but accidentally, rightly explains it, each relative would not be referred to one, but to many things, as there is nothing to prevent the same thing, being both white, and good, so that he who explains by reference to one of these, would rightly explain, if he who explains from accident, does so rightly. Moreover, it is impossible that such a definition as this, should be peculiar to the thing assigned, for not only medicine, but many other sciences are referred to what exists, so that each will be the science of being; wherefore it is clear that such is the definition of no science, for it is necessary that definition should be peculiar, and not common.
Sometimes indeed, they define not the thing (only), but a thing in a good condition, or perfect; such is the definition of a rhetorician, and of a thief, since a rhetorician is one who is able to perceive what is persuasive in each thing, and to omit nothing; but a thief is one who takes on the sly, for it is evident that each being such, will be good, the one a good rhetorician, but the other a good thief, for not he who pilfers secretly is a thief, but he who wishes to pilfer secretly.
Again, (he errs,) who assigns what is of itself eligible, as practical or efficient, or in any way eligible on account of something else; as if he said that justice, is the preserver of the laws, or that wisdom, is effective of felicity, for what is effective, or preservative, is of the number of things eligible on account of something else. Or does nothing prevent what is eligible for itself, being eligible for something else also? nevertheless, he errs, who thus defines what is eligible per se, since in every thing, the best especially subsists in the essence, but it is better to be eligible per se, than on account of something else, so that definition ought of necessity rather to signify this.
Chapter 13
Consider besides, whether he who assigns the definition of a certain thing, defines that it is
