“Of One Substance” and “Of Like Substance”

From the beginning the emperors had kept their father’s view of doctrine, for both of them favored the Nicene form of belief. Constans held to these opinions until his death. Constantius held the same view for some time; but he gave up his former position when the term “of one substance” came under attack, though even then he did not altogether stop confessing that the Son is of like substance with the Father. The followers of Eusebius, and other bishops of the East who were admired for their speaking and their lives, made a distinction, as we know, between the term “of one substance,” homoousios, and the expression “of like substance,” which they called homoiousios. They say that the term “of one substance,” homoousios, properly belongs to bodily beings, such as human beings and other animals, trees and plants, which share in things like themselves and have their origin from them; but that the term homoiousios belongs only to beings without bodies, such as God and the angels, each of whom is conceived of according to his own particular substance. [a]

The emperor Constantius was misled by this distinction. And although I am certain that he kept the same doctrines as his father and his brother, he changed his wording and used the term homoiousios instead of homoousios. The teachers I have mentioned held that it was necessary to be this precise in the use of terms, since otherwise we would be in danger of thinking of something without a body as though it were a body. Many, however, regard this distinction as absurd. “For,” they say, “the things the mind conceives can be named only by words taken from things that are seen; and there is no danger in the use of words, so long as there is no error about the idea.”