"Co-ordinates[1] and derivatives and inflections are thought to be comparable with one another, but still distinct. [Things] are said to belong to the same kind when they have similar relations to one another, which could also be said by analogy, like knowledge and perception. For each of these has a similar relation to their [respective] objects. Both the object of sensation and the object of knowledge are related similarly; for each object has a similar relation to those things to which they pertain [i.e. sensation and knowledge]. They also call[2] what belongs to the same kind[3] both all those things which are named after something in relation to another and with respect to that one after which they are all named, e.g. 'the just,' 'the one who is just,' and 'the one who acts justly' are derived from 'justice.' So, what belongs to the same kind is, to be sure, each of these with respect to one another and to justice itself. However, they say derivatives are those which are named after something only with respect to that one by which they are so named, and neither according to each other nor is that one thing named after them. [For] 'grammarian' [is named] after 'grammar' and not 'grammar' after 'grammarian.'