Chapter 31

Those things are equivocal which have a common name, but which differ in their definition or description. The term dog, for example, is an equivocal one, because it means both the land-dog and the sea-dog. The land-dog, however, has one definition, while the sea-dog has another, because one is one nature and the other is another. Now, equivocals are described as follows: those things are equivocal which have only their name in common, while the statement of the substances signified by the name is diverse. Take ‘statement’ here as meaning definition or description; and take ‘by the name as showing that the definitions of the name are diverse, for which reason the things are equivocal. Take, for example, the land-dog and the sea-dog. These are equivocal because of their name—dog. For, should anyone wish to give the definition of the land-dog and of the sea-dog, he will, in so far as each one of them is called a dog, give one definition of dog to the land one and another to the sea one. Nevertheless, it is possible for these to have a common definition as well as a common name. Thus, both are called animals and admit of the definition of the animal. In the name of animal, however, they are not equivocal, but univocal. Moreover, in the case of equivocal things one must ask three questions, namely: whether it is equivocal, in how many senses it is taken, and which meaning is in question.

Although the ancients were of the opinion that likeness arose in four ways from quality alone, the more recent have thought that primarily and summarily it arises both from substance and quality. There is likeness in substance, as when we say that men are like angels, implying that they are equal to them, even though in their qualities men and angels do differ from each other very much. And in the same way we speak of horses, swans, and the like. However, since this likeness sometimes appears as without variance and sometimes with some variance, the heretics who made the Son to be inferior would say that He was like the Father, and thus by the ambiguity of the term they would lead astray more simple folk. It is for this very reason that Basil the Great says: cIf the “without variance” be added, then I, too, accept it. So much, then, for likeness in substance. Likeness in quality is not just in this quality or that, but in every quality—that is to