Summa contra Gentiles1.34 Chapter XXXIV. That terms applied to God and creatures are employed analogically

It follows, then, from what has been said that those things which are said of God and other things are predicated neither univocally nor equivocally, but analogically, that is according to an order or relation to some one thing.

This happens in two ways. First, according as many things have a relation to some one thing: thus in relation to the one health, an animal is said to be healthy as its subject, medicine as effective thereof, food as preserving it, and urine as its sign. Secondly, according as order or relation of two things may be observed, not to some other thing, but to one of them: thus being is said of substance and accident, in so far as accident bears a relation to substance, and not as though substance and accident were referred to a third thing.

Accordingly such names are not said of God and other things analogically in the first way, for it would be necessary to suppose something previous to God; but in the second way.

Now in this analogical predication the relationship is 1 Chs. xxxii., xxxiii.

sometimes found to be the same both as to the name and as to the thing, and sometimes it is not the same. For the relationship of the name is consequent upon the relationship of knowledge, since the name is the sign of intellectual conception. Accordingly when that which comes first in reality is found to be first also in knowledge, the same thing is found to be first both as to the meaning of the name and as to the nature of the thing: thus substance is prior to accident both in nature, in as much as substance is the cause of accident, and in knowledge, in as much as substance is placed in the definition of accident. Wherefore being is said of substance previously to being said of accident, both in reality and according to the meaning of the word. On the other hand, when that which comes first according to nature, comes afterwards according to knowledge, then, in analogical terms, there is not the same order according to the reality and according to the meaning of the name: thus the healing power in health-giving (medicines) is naturally prior to health in the animal, as cause is prior to effect; yet as we know this power through its effect, we name it from that effect. Hence it is that health-giving is first in the order of reality, and yet healthy is predicated of animal first according to the meaning of the term.

Accordingly, since we arrive at the knowledge of God from other things, the reality of the names predicated of God and other things is first in God according to His mode, but the meaning of the name is in Him afterwards. Wherefore He is said to be named from His effects.