Spirituality & Light - What/Why the connection?

Enter the classic mystical understanding of consciousness as light. This is an ancient and well-worn metaphor, but it takes on a new life in the second half of the nineteenth century as physicists began to discover that visible light is in fact only a small part of a much larger spectrum of energy. Hence Myers’s aforementioned “spectrum of consciousness” through which he sought to draw “a comparison of man’s range of consciousness or faculty to the solar spectrum, as seen by us after passing through a prism or examined in a spectrascope” (HP 1:xxi). Myers uses such a prismatic effect to suggest that the light of consciousness is not singular at all, that consciousness can be broken up into various bands, much like white light can be separated into a rainbow of colors. Most of the light spectrum, moreover, particularly that beyond the infrared (on the lower end) and ultraviolet (on the higher end), appears well outside the bands of everyday awareness. Similarly, Myers suggested, most of the spectrum of consciousness is entirely invisible to our normal senses and present egoic form of awareness.

Kripal, Jeffrey J.. Authors of the Impossible: The Paranormal and the Sacred (p. 65). University of Chicago Press. Kindle Edition.