Chapter 8
If indeed what is defined should either be per se, or generically, a relative, consider whether that to which it is referred, either per se, or generically, has not been mentioned in the definition, as if some one had defined science to be immutable opinion, or the will, appetite unattended with pain. For the essence of every relative consists in a relation to something else, since the being of every thing which subsists with reference to another thing, is the same with that of being in a certain respect referred to something; wherefore it is necessary to say that science, is the opinion of the object of science, and the will, the appetency of good. Likewise, also, if a person defined grammar to be the science of letters, since it will be necessary in the definition to assign that to which the thing defined, or to which the genus, is referred. Also (consider), whether the definition of a certain thing referred to something, is not assigned with reference to the end; now the end in each thing is that which is best, or on account of which other things subsist, wherefore, either what is best, or what is last, must be stated; e. g. that desire is not of the pleasant, but of pleasure, for we even choose the pleasant for the sake of this.
Examine, moreover, whether that to which a thing is referred, be generation or energy, since nothing of this kind is an end; for to have energized, or to have been generated, are rather the end, than to generate or to energize, or is it not that such a thing as this is true in all, for almost all men rather desire to be delighted than to cease being delighted, so that they rather make the end to energize than to have energized?
In some cases again, (we must notice) whether there is not a definition of the quantity or quality, or the where, or according to the other differences; for instance, what the quality or quan-
