From Swedenborg and Esoteric Islam by Henri Corbin, Translated by Leonard Fox:

...alam al-mithal, the world of the Image, mundus imaginalis: a world as ontologically real as the world of the senses and the world of the intellect, a world that requires a faculty of perception belonging to it, a faculty that is a cognitive function, a noetic value, as fully real as the faculties of sensory perception, or intellectual intuition. This faculty is the imaginative power, the one we must avoid confusing with the imagination that modern man identifies with "fantasy" and that, according to him, produces only the "imaginary."

I have proposed the Latin term mundus imaginalis for it, because we are obliged to avoid any confusion between what is here the object of imaginative or imaginal perception and what we ordinarily call the imaginary. This is so because the current attitude is to oppose the real to the imaginary as though to the unreal, the utopian, as it is to confused symbol with allegory, to confuse the exegesis of the spiritual sense with an allegorical interpretation.

...the appearance of an Image having the quality of a symbol is a primary phenomena (Urphanomen), unconditional and irreducible, the appearance of something that cannot manifest itself otherwise to the world where we are.

If we do not have available a cosmology whose schema can include, as does the one that belongs to our traditional philosophers, the plurality of universes in ascensional order, our Imagination will remain unbalanced, its recurrent conjunctions with the will to power will be an endless source of horrors. We will be continually searching for a new discipline of the Imagination, and we will have great difficulty in finding it as long as we persist in seeing in it only a certain way of keeping our distance with regard to what we call the real, and in order to exert an influence on that real.

For instead of the image being elevated to the level of a world that would be proper to it, instead of it appearing invested with a symbolic function, leading to an internal sense, there is above all a reduction of the image to the level of sensory perception pure and simple, and thus a definitive degradation of the image. Should it not be said, therefore, that the more successful this reduction is, the more the sense of the imaginal is lost, and the more we are condemned to producing only the imaginary? it not precisely this postulate of the objectivity of the imaginalworld that is suggested to us, or imposed on us, by certain forms or certain symbolic emblems (hermetic, kabbalistic; or mandalas) that have the quality of effecting a magic display of mental images, such that they assume an objective reality?

M.C. Escher,
Henri Corbin (1903-78) was a French orientalist, philosopher, and mystic. Corbin organized, in 1946, the Department of Iranology of the Franco-Iranian Institute in Tehran. There he established and directed the Bibliothèque Iranienne Series, an important collection of editions of Persian and Arabic texts together with analytical studies. From 1954 to 1974 he held the position of directeur d'études at the Ecole Pratique des Hautes Études at the Sorbonne University. He is also recognized as the as "second father" (after C.G. Jung) of archetypal psychology. He posited Jung's "mundus archetypalis" is also the "mundus imaginalis" and corresponds to the Islamic alam al-mithl.

Henry CorbinHis many publications in French and translated into English include Avicenna and the Visionary Recital (1960), Creative Imagination in the Sufism of Ibn'Arabi (1969), Spiritual Body and Celestial Earth (1977) and The Man of Light in Iranian Sufism (1978).