“…It is quite evident that the mental vision of the Angel of the Earth, for example, is not a sensory experience. If, by logical habit, we classify this fact as imaginary, the question nonetheless remains as to what can justify an identification of what is imaginary with what is arbitrary and unreal, the question as to whether representations deriving from physical perception are the only ones to be considered as real knowledge, whether physically verifiable events alone can be evaluated as facts. We must ask ourselves whether the invisible action of forces that have their purely physical expression in natural processes may not bring into play psychic energies that have been neglected or paralyzed by our habits, and directly touch an Imagination which, far from being arbitrary invention corresponds to that Imagination which the alchemists called Imaginatio vera and which is the astrum in homine.

The active Imagination thus induced will not produce some arbitrary, even lyrical, construction standing between us and “reality,” but will, on the contrary, function directly as a faculty and organ of knowledge just as real as – if not more real than – the sense organs. However, it will perceive in the manner proper to it: the organ is not a sensory faculty but an archetype-Image that it possessed from the beginning; it is not something derived from any outer perception. And the property of this Image will be precisely that of effecting the transmutation of sensory data, their resolution into the purity of the subtle world, in order to restore them as symbols to be deciphered, the “key” being imprinted in the soul itself. Such perception through the Imagination is therefore equivalent to a “dematerialization”; it changes the physical datum impressed upon the senses in a pure mirror, a spiritual transparency; thus it is that the Earth, and the things and beings of the Earth, raised to incandescence, allow the apparition of their Angels to penetrate to the visionary intuition. This being so, the authenticity of the Event and its full reality consist essentially of this visionary act and of the apparition vouchsafed by it.

Thus is constituted this intermediary world, a world of archetypal celestial figures which the active Imagination alone is able to apprehend. This Imagination does not construct something unreal, but unveils the hidden reality; its action is, in short, that of the ta’wil, the spiritual exegesis, [...] and that of alchemical meditation: to occultate the apparent, to manifest the hidden. It is in this intermediary world that those known as the urafa, the mystical Gnostics, have mediated tirelessly, gnosis here being taken to mean that perception which grasps the object not in its objectivity, but as a sign, an intimation, and announcement that is finally the soul’s annunciation to itself.”

Henry Corbin, "Spiritual Body and Celestial Earth," Princeton/Bollingen, 1977.