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relations. Therefore equality is not becoming to the divine persons.
_On the contrary,_ Athanasius says that "the three persons are co-eternal and co-equal to one another."
_I answer that,_ We must needs admit equality among the divine persons. For, according to the Philosopher (Metaph. x, text 15, 16, 17), equality signifies the negation of greater or less. Now we cannot admit anything greater or less in the divine persons; for as Boethius says (De Trin. i): "They must needs admit a difference [namely, of Godhead] who speak of either increase or decrease, as the Arians do, who sunder the Trinity by distinguishing degrees as of numbers, thus involving a plurality." Now the reason of this is that unequal things cannot have the same quantity. But quantity, in God, is nothing else than His essence. Wherefore it follows, that if there were any inequality in the divine persons, they would not have the same essence; and thus the three persons would not be one God; which is impossible. We must therefore admit equality among the divine persons.
Reply Obj. 1: Quantity is twofold. There is quantity of "bulk" or dimensive quantity, which is to be found only in corporeal things, and has, therefore, no place in God. There is also quantity of "virtue," which is measured according to the perfection of some nature or form: to this sort of quantity we allude when we speak of something as being more, or less, hot; forasmuch as it is more or less, perfect in heat. Now this virtual quantity is measured firstly by its source--that is, by the perfection of that form or nature: such is the greatness of spiritual things, just as we speak of great heat on account of its intensity and perfection. And so Augustine says (De Trin. vi, 18) that "in things which are great, but not in bulk, to be greater is to be better," for the more perfect a thing is the better it is. Secondly, virtual quantity is