Book 7
9
It follows, therefore, that there are three sorts of friendship, and that they are not all so termed in respect of one thing or as species of one genus, nor yet have they the same name entirely by accident. For all these uses of the term are related to one particular sort of friendship which is primary, like the term surgical —and we speak of a surgical mind and a surgical hand and a surgical instrument and a surgical operation,but we apply the term properly to that which is primarily so called.
10
The primary is that of which the definition is implicit in the definition of all, for example a surgical instrument is an instrument that a surgeon would use, whereas the definition of the instrument is not implicit in that of surgeon.
11
Therefore in every case people seek the primary, and because the universal is primary they assume that also the primary is universal; but this is untrue. Hence in the case of friendship, they cannot take account of all the observed facts. For as one definition does not fit, they think that the other kinds of friendship are not friendships at all; but really they are, although not in the same way,
12
but when they find that the primary friendship does not fit, assuming that it would be universal if it really were primary, they say that the others are not friendships at all.
