“To invoke is to call in, just as to evoke is to call forth. This is the essential difference between the two branches of Magick. In invocation, the macrocosm floods the consciousness. In evocation, the magician, having become the macrocosm, creates a microcosm.” - Magick in Theory and Practice, Aleister Crowley
Invocation vs. Evocation: Internal calling (invocation) vs. external summoning (evocation).
Invocation & Evocation
Calling in and Calling out
Calling in And Calling forth
"All the spirits, and as it were the essences of all things, lie hid in us, and are born and brought forth only by the working, power (will) and phantasy (imagination) of the microcosm." - The Magus. Francis Barrett.
Invoking - calling upon higher, more subtle, or more pure energies to replace the lower energies that have been banished. Most often these energies take the form of deities, Archangels, and angels.