Emanationism, the doctrine that emanation (Lat. emanare, "to flow from") is the mode by which all things are derived from the First Reality, or Principle.
I. The term emanation, being itself a metaphor, has been, and is still, used in many senses, and frequently by writers who are not emanationists. Others, without using the word, really hold the doctrine of emanation. Furthermore, emanationism is always interwoven with different opinions on various subjects; to separate it from these so as to assign its fundamental elements is more or less arbitrary. Taking emanationism in the sense commonly received today, it is not primarily a theological, but rather a cosmogonic system, not a direct answer to the question of the nature of God, but to that of the mode of origin of things from God. In general it holds that all things proceed from the same Divine substance, some immediately, others mediately. All beings form a series the beginning of which is God. The second reality is an emanation from the first, the third from the second, and so on. At every step the derived being is less perfect than its source; but, by giving rise to other beings, the source itself loses none of its perfections. The first source, then, from which everything flows, remains unchanged; its perfection is neither exhausted nor lessened.
Emanationism is frequently referred to as a form of pantheism; but while this latter is primarily a system of reality, identifying all things as modes or appearances of the one substance, emanationism is concerned chiefly with the mode of derivation. Nor does it necessarily affirm the substantial identity of all things; it may assert the distinct, though dependent, substantiality of emanated realities. It is true that emanation is conceived by some in a pantheistic sense, as an immanent process, an expansion of the Divine substance within itself. But by many it is understood as implying a separation of the derived beings from their source. Hence, not only some forms of pantheism are not emanationistic, but also many emanationists—with more or less consistency—reject pantheism. For those who admit that matter is eternal and exists independently of God, God cannot be more than an architect, who arranges pre-existing materials. In the doctrine of complete emanationism, all things, from the highest spiritual substances to the lowest forms of matter, come from God as their first origin, matter being the last and therefore most imperfect emanation. Some views, however, combine the theory of the eternity of matter with the theory of emanation.
The doctrine of creation teaches that all things are distinct from God, but that God is their efficient cause. God does not produce things from His own substance nor from any pre-existing reality, but by an act of His will brings them out of nothing. According to emanationism, on the contrary, the Divine substance is the reality from which all things are derived, not by any voluntary determination, but by a necessity of nature. And God does not produce all things immediately; the lower are more distant, and are separated from Him by necessary intermediaries. (It may be noted, however, that sometimes the word emanation is used in a broader sense including also creation. Thus St. Thomas: "Quaeritur de modo emanationis rerum a primo principio qui dicitur creatio".—Summa, I, Q. xlv, a. 1.)
Evolution implies the change of one thing into something else, whereas a reality from which another emanates remains identical with itself. The process of evolution—at least in its totality—is generally considered as an ascent, a movement upwards towards a greater perfection. Emanation is a descent; it begins with the infinitely perfect, and at every step the emanating beings are less pure, less perfect, less divine. The Infinite is postulated as a starting point, instead of being the goal which the universe is ever striving to realize. Some comparisons used by emanationists, though only metaphors, and consequently misleading if taken literally, may give a clearer idea of the system. Things proceed from God as water from a spring or an overflowing vessel; as the stem, branches, leaves, etc., from the roots; as the web from the spider; as light or heat from the sun or a fire; as the doctrine from the teacher. It is easy to see that all such comparisons are deficient in many points. They are intended simply to illustrate that which is above human comprehension.