Chapter 50

Those things are relative which, in what they themselves are, are said to belong to other things, or they are those which in any other way whatsoever are related to another thing. Now, they are said to belong to others, as a father to a son, for the father is necessarily said to be father of a son. On the other hand, they are related to another, as great is to little or much to little. For ‘much is not said to belong to ‘little, but to be ‘much in relation to ‘little.’

One should know that, whenever a thing is considered in itself, it is not relative. When, however, it has a habitude to another thing, then it is said to be relative. Here, then, is the essence of relatives and here is their hypostasis; namely, in their being said to be relative to another, that is to say, in their having a habitude to another. For it is their mutual habitude which makes things relative.

Some relatives are called by the same name, as a friend is a friend of a friend and as an enemy is an enemy of an enemy. Others are called by different names, as a father is a father of a son and as a teacher is a teacher of a pupil.

And again, some things are relative by excess, as the greater is greater than the less. Others are relative according to the relation of the thing discerning to the thing discerned, as scientific knowledge is the knowledge of that which is scientifically knowable. For science discerns that which is scientifically knowable, or, in other words, cognition discerns that which is knowable. And also, sensation is a feeling of the sensible object, placing is a placing of that which is placeable, standing is a standing of that which can stand, reclining is a reclining of that which can recline, and so on. Still others are relative according to potency and impotency. They are relative according to potency, as are the thing heating and the thing heated; according to impotency, or the privation of potency, as when we say that the eye does not have the power to see the sphere without stars. Others are relative according to the relation between the cause and the thing caused, as a father is a father of a son.

Proper to relatives is the fact that they may be affirmed convertibly. Thus, a friend is a friend of a friend, and the second