the definition has not been sufficiently framed, but those things are relatives, whose substance is the same, as consists with a relation, after a certain manner, to a certain thing; somewhat, perhaps, in reply to this, may be stated. The former definition, however, concurs with all relatives, yet it is not the same thing, that their being, consists in relation, and that being what they are, they are predicated of other things. 17. One relative being known, the correlative can be known. Hence it is clear, that he who knows any one relative, definitely, will also know what it is referred to, definitely. Wherefore also from this it is apparent, that if one knows this particular thing to be among relatives, and if the substance of relatives is the same, as subsisting in a certain manner, with reference to something, he will also know that, with reference to which, this particular thing, after a certain manner, subsists; for if, in short, he were ignorant of that, with reference to which, this particular thing, after a certain manner, subsists, neither would he know, whether it subsists, after a certain manner, with reference to something. 18. Singulars. And in singulars, indeed, this is evident; for if any one knows definitely, that this thing is "double," he will also forthwith know that, definitely, of which it is the double, since if he knows not that it is the double, of something definite, neither will he know that it is "double," at all. So again, if a man knows this thing, to be more beautiful than something else, he must straightway and definitely know that, than which, it is more beautiful. Wherefore, he will not indefinitely know, that this, is better, than that which is worse, for such is opinion and not science, since he will not accurately know that it is better than something worse, as it may so happen that there is nothing worse than it, whence it is necessarily evident, that whoever definitely knows any relative, also definitely knows that, to which it is referred. 19. The converse true of secondary substances. It is possible, notwithstanding, to know definitely what the head, and the hand, and every thing of the sort are, which are substances; but it is not necessary to know that to which they are referred, since it is not necessary definitely to know whose, is the head, or whose, is the hand; thus these will not be relatives, but if these be not relatives, we may truly affirm no substance to be among relatives. It is, perhaps, difficult for a man to assert assuredly
