Emanationism explains the origin and structure of reality by postulating a perfect and transcendent principle from which everything is derived through a process called emanation (Greek aporroia, probolē, proodos; Latin emanatio), which is comparable to an efflux or radiation. Emanation is timeless and thus can be called a process only figuratively. It leaves its source undiminished, so that the source remains transcendent; but as the process continues, each of its products is less perfect.

In these three respects emanationism is opposed to evolutionism because evolution is a temporal process in which the principle itself is involved (immanent) and in which an increase in perfection is usually conceived. Emanationism is also opposed to creationism, according to which the principle creates the rest of reality (from which it differs absolutely), either out of nothing or by transforming a preexisting, chaotic matter into a cosmos. There is some affinity between emanationism...