Ousia
Ousia () is the
Greek word for
essence or substance[
1]. Initially it was a technical term used by Greek
philosophers such as
Plato and most importantly
Aristotle.
Aristotle used the term in his creation of
phyla for animals in biology. Aristotle used substance and hypostasis in the sense that one would be a general existence -hypostasis, the other "substance or ousia" would refer to specific individual things or beings.
Martin Heidegger later used the term in relation to Aristotle to mean being and
apousia to mean being-ness and the term
hypostasis to mean existence.
Origen, (c. 182 – c. 251) used it when he said God is one genus of ousia yet three distinct species of
hypostasis: namely the Father, the Son, and the Holy Spirit.
The
Synods of Antioch in 264-268 condemned the term
homoousios (same substance) because of its Greek language and philosopher roots. The
Gnostics said Jesus and God were homoousios (of same substance). The
Catholic Encyclopedia article on
Paul of Samosata [
2] states:
It must be regarded as certain that the council which condemned Paul rejected the term homoousios; but naturally only in a false sense used by Paul; not, it seems because he meant by it an unity of Hypostasis in the Trinity (so St. Hilary), but because he intended by it a common substance out of which both Father and Son proceeded, or which it divided between them, â€" so St. Basil and St. Athanasius; but the question is not clear. The objectors to the Nicene doctrine in the fourth century made copious use of this disapproval of the Nicene word by a famous council.The
First Council of Nicaea in 325 debated the terms
homoousios and
homoiousios. The word homoousios means "same substance", whereas the word homoiousios means "similar substance". The council affirmed the Father, Son, and Holy Spirit (Godhead) are of the homoousious (same substance). This is the source of the English idiom "differ not by one
iota." Note that the words homoousios and homoiousios differ only by one 'i' (or the Greek letter iota). Thus, to say two things differ not one iota, is to say that they are the same substance.
The
Chalcedonian Creed of 451 stated God is one ousia yet three hypostases.
*
Consubstantial* Leo Donald Davis, The First Seven Ecumenical Councils (325-787): Their History and Theology, Liturgical Press, 1983. (ISBN 0814656161)
* Martin Heidigger, Being and Time.
*
Vladimir Lossky The Mystical Theology of the Eastern Church, SVS Press, 1997. (ISBN 0913836311) James Clarke & Co Ltd, 1991. (ISBN 0227679199)
*
Catholic Encyclopedia: Homoousion*
P.F. Beatrice: The Word "Homoousios" from Hellenism to Christianity
