The Ante-Nicene history of the word homoüsion or consubstantial, which the Council of Nicæa adopted as its test, will introduce a more important discussion.

It is one characteristic of Revelation, that it clears up all doubts about the existence of God, as separate from, and independent of nature; and shows us that the course of the world depends not merely on a system, but on a Being, real, living, and individual. What we ourselves witness, evidences to us the operation of laws, physical and moral; but it leaves us unsatisfied, whether or not the principle of these be a mere nature or fate, whether the life of all things be a mere Anima Mundi, a spirit connatural with the body in which it acts, or an Agent powerful to make or unmake, to change or supersede, according to His will. It is here that Revelation supplies the deficiency of philosophical religion; miracles are its emblem, as well as its credentials, forcing on the imagination the existence of an irresponsible self-dependent Being, as well as recommending a particular message to the reason.

This great truth, conveyed in the very circumstances under which Revelation was made, is explicitly recognized in its doctrine. Among other modes of inculcating it, may be named the appellation under which Almighty God disclosed Himself to the Israelites; Jehovah (or, as the Septuagint translates it, [ho on]) being an expressive appellation of Him, who is essentially separate from those variable and perishable beings or substances, which creation presents to our observation. Accordingly, the description of Him as [to on], or in other words, the doctrine of the [ousia] of God, that is, of God viewed as Being and as the one Being, became familiar to the minds of the primitive Christians; as embodying the spirit of the Scriptures, and indirectly witnessing against the characteristic error of pagan philosophy, which considered the Divine Mind, not as a reality, but as a mere abstract name, or generalized law of nature, or at best as a mere mode, principle, or an animating soul, not a Being external to creation, and possessed of individuality. Cyril of Alexandria defines the word [ousia], (usia, being, substance,) to be "that which has existence in itself, independent of every thing else to constitute it;" that is, an individual.

This sense of the word must be carefully borne in mind, since it was not that in which it is used by philosophers, who by it denoted the genus or species, or the "ens unum in multis,"—a sense which of course it could not bear when applied to the One Incommunicable God. The word, thus appropriated to the service of the God of Revelation, was from the earliest date used to express the reality and subsistence of the Son; and no word could be less metaphorical and more precise for this purpose, although the Platonists chose to refine, and from an affectation of reverence refused to speak of God except as hyperusios. Justin Martyr, for instance, speaks of heretics, who considered that God put forth and withdrew His Logos when it pleased Him, as if He were an influence, not a Person, somewhat in the sense afterwards adopted by Paulus of Samosata and others. To meet this error, he speaks of Him as inseparable from the substance or being, usia, of the Father; that is, in order to exclude all such evasions of Scripture, as might represent the man Christ as inhabited by a divine glory, power, nature, and the like, evasions which in reality lead to the conclusion that He is not God at all.

For this purpose the word homoüsion or consubstantial was brought into use among Christian writers; viz. to express the real divinity of Christ, and that, as being derived from, and one with the Father's. Here again, as in the instance of its root, the word was adopted, from the necessity of the case, in a sense different from the ordinary philosophical use of it. Homoüsion properly means of the same nature, or under the same general nature, or species; that is, it is applied to things, which are but similar to each other, and are considered as one by an abstraction of our minds; or, it may mean of the same material. Thus Aristotle speaks of the stars being consubstantial with each other; and Porphyry of the souls of brute animals being consubstantial to ours [Note 13]. When, however, it was used in relation to the incommunicable Essence of God, there was obviously no abstraction possible in contemplating Him, who is above all comparison with His works. His nature is solitary, peculiar to Himself, and one; so that whatever was accounted to be consubstantial or co-essential with Him, was necessarily included in His individuality, by all who would avoid recurring to the vagueness of philosophy, and were cautious to distinguish between the incommunicable Essence of Jehovah and all created intelligences. And hence the fitness of the term to denote without metaphor the relation which the Logos bore in the orthodox creed to His eternal Father. Its use is explained by Athanasius as follows. "Though," he says, "we cannot understand what is meant by the usia, being, or substance of God, yet we know as much as this, that God is, which is the way in which Scripture speaks of Him; and after this pattern, when we wish to designate Him distinctly, we say God, Father, Lord. When then He says in Scripture, 'I am [hoon],' the Being, and 'I am Jehovah, God,' or uses the plain word 'God,' we understand by such statements nothing but His incomprehensible {188} [ousia] (being or substance), and that He, who is there spoken of, is. Let no one then think it strange, that the Son of God should be said to be [ek tes ousias] (from the being or substance) of God; rather, let him agree to the explanation of the Nicene fathers, who, for the words 'of God' substituted 'of the divine being or substance.' They considered the two phrases substantially the same, because, as I have said, the word 'God' denotes nothing but the [ousia autou tou ontos], the being of Him who is. On the other hand, if the Word be not in such sense 'of God,' as to be the true Son of the Father according to His nature, but be said to be 'of God,' merely as all creatures are such because they are His work, then indeed He is not 'from the being of the Father,' nor Son 'according to being or substance,' but so called from His virtue, as we may be, who receive the title from grace." 

The term homoüsios is first employed for this purpose by the author of the Pæmander, a Christian of the beginning of the second century. Next it occurs in several writers at the end of the second and the beginning of the third. In Tertullian, the equivalent phrase, "unius substantiæ," "of one substance," is applied to the Trinity. In Origen's comment on the Hebrews, the homoüsion of the Son is deduced from the figurative title [apaugasma], or radiance, there given to Him. In the same age, it was employed by various writers, bishops and historians, as we learn from the testimonies of Eusebius and Athanasius. But at this era, the middle of the third century, a change took place in the use of it and other similar words, which is next to be explained.

The oriental doctrine of Emanations was at a very early period combined with the Christian theology. According to the system of Valentinus, a Gnostic heresiarch, who flourished in the early part of the second century, the Supreme Intelligence of the world gave existence to a line of Spirits or Eons, who were all more or less partakers of His nature, that is, of a nature specifically the same, and included in His glory ([pleroma]), though individually separate from the true and Sovereign Deity. It is obvious, that such a teaching as this abandons the great revealed principle above insisted on, the incommunicable character and individuality of the Divine Essence. It considers all spiritual beings as like God, in the same sense that one man resembles or has the same nature as another: and accordingly it was at liberty to apply, and did actually apply, to the Creator and His creatures the word homoüsion or consubstantial, in the philosophical sense which the word originally bore. We have evidence in the work of Irenæus that the Valentinians did thus employ it. The Manichees followed, about a century later; they too were Emanatists, and spoke of the human soul as being consubstantial or co-essential with God, of one substance with God. Their principles evidently allowed of a kind of Trinitarianism; the Son and Spirit being considered Eons of a superior order to the rest, consubstantial with God because Eons, but one with God in no sense which was not true also of the soul of man. It is said, moreover, that they were materialists; and used the word consubstantial as it may be applied to different vessels or instruments, wrought out from some one mass of metal or wood. However, whether this was so or not, it is plain that anyhow the word in question would become unsuitable to express the Catholic doctrine, in proportion as the ears of Christians were familiarised to the terms employed in the Gnostic and Manichean theologies; nor is it wonderful that at length they gave up the use of it.

The history of the word probole or offspring is parallel to that of the consubstantial [Note 16]. It properly means any thing which proceeds, or is sent forth from the substance of another, as the fruit of a tree, or the rays of the sun; in Latin it is translated by prolatioemissio, or editio, an offspring or issue. Accordingly Justin employed it, or rather a cognate phrase [Note 17], to designate what Cyril calls above the self-existence of the Son, in opposition to the evasions which were necessary for the system of Paulus, Sabellius, and the rest. Tertullian does the same; but by that time, Valentinus had given the word a material signification. Hence Tertullian is obliged to apologize for using it, when writing against Praxeas, the forerunner of the Sabellians. "Can the Word of God," he asks, "be unsubstantial, who is called the Son, who is even named God? He is said to be in the form or image of God. Is not God a body [substance], Spirit though He be? ... Whatever then has been the substance of the Word, that, I call a Person, and claim for it the name of Son, and being such, He comes next to the Father. Let no one suppose that I am bringing in the notion of {191} any such probole (offspring) as Valentinus imagined, drawing out his Eons the one from the other. Why must I give up the word in a right sense, because heresy uses it in a wrong? besides, heresy borrowed it from us, and has turned truth into a lie … This is the difference between the uses of it. Valentinus separates his probolæ from their Father; they know Him not. But we hold that the Son alone knows the Father, reveals Him, performs His will, and is within Him. He is ever in the Father, as He has said; ever with God, as it is written; never separated from Him, for He and the Father are one. This is the true probole, the safeguard of unity, sent forth, not divided off." Soon after Tertullian thus defended his use of the word probole, Origen in another part of the Church gave it up, or rather assailed it, in argument with Candidus, a Valentinian. "If the Son is a probole of the Father," he says, "who begets Him from Himself, like the birth of animals, then of necessity both offspring and original are of a bodily nature." Here we see two writers, with exactly the same theological creed before them, taking opposite views as to the propriety of using a word which heresy had corrupted.

But to return to the word consubstantial: though Origen gave up the word probole, yet he used the word consubstantial, as has already been mentioned. But shortly after his death, his pupils abandoned it at the celebrated Council held at Antioch (A.D. 264) against Paulus of Samosata. When they would have used it as a test, this heretic craftily objected to it on the very ground on which Origen had surrendered the probole. He urged that, if Father and Son were of one substance, consubstantial, there was some common substance in which they partook, and which consequently was distinct from and prior to the Divine Persons Themselves; a wretched sophism, which of course could not deceive Firmilian and Gregory, but which, being adapted to perplex weak minds, might decide them on withdrawing the word. It is remarkable too, that the Council was held about the time when Manes appeared on the borders of the Antiochene Patriarchate. The disputative school of Paulus pursued the advantage thus gained; and from that time used the charge of materialism as a weapon for attacking all sound expositions of Scripture truth. Having extorted from the Catholics the condemnation of a word long known in the Church, almost found in Scripture, and less figurative and material in its meaning than any which could be selected, and objectionable only in the mouths of heretics, they employed this concession as a ground of attacking expressions more directly metaphorical, taken from visible objects, and sanctioned by less weighty authority. In a letter which shall afterwards be cited, Arius charges the Catholics with teaching the errors of Valentinus and Manes; and in another of the original Arian documents, Eusebius of Nicomedia, maintains in like manner that their doctrine involves the materiality of the Divine Nature. Thus they were gradually silencing the Church by a process which legitimately led to Pantheism, when the Alexandrians gave the alarm, and nobly stood forward in defence of the faith.

It is worth observing that, when the Asiatic Churches had given up the consubstantial, they, on the contrary, had preserved it. Not only Dionysius willingly accepts the challenge of his namesake of Rome, who reminded him of the value of the symbol; but Theognostus also, who presided at the Catechetical School at the end of the third century, recognizes it by implication in the following passage, which has been preserved by Athanasius. "The substance of the Son," he says, "is not external to the Father, or created; but it is by natural derivation from that of the Father, as the radiance comes from light (Heb. i. 3). For the radiance is not the sun, ... and yet not foreign to it; and in like manner there is an effluence ([aporrhoia], Wisd. vii. 25.) from the Father's substance, though it be indivisible from Him. For as the sun remains the same without infringement of its nature, though it pour forth its radiance, so the Father's substance is unchangeable, though the Son be its Image."