The underground stream is always present, always speaking to us across the full range of human experience. However, the mature visions normally drown out its voice. They act as a kind of control valve that causes us to dismiss the magical assumptions of the underground stream as implausible and unfounded.
It’s only when an aging vision starts to falter that the underground stream is able to break through in the specific area covered by that vision. For example, when the reason vision began failing in the 1880s, it provided an opening for unrestrained speculation about the potentials of the human mind.
The successor to reason — the chaos vision — was still very close to its mystical roots then, and its focus on non-rational states of consciousness such as dream, madness, and intoxication was entirely compatible with the raw shamanistic perceptions of spiritualists and occultists.
The idea of psychic abilities, in particular, was considered worthy of serious scientific investigation. When the Society for Psychical Research was founded in London in 1882, it had a range of interests that encompassed everything from thought-transference and mesmerism to spirit mediums and haunted houses. Its mission was “to approach these varied problems without prejudice or prepossession of any kind, and in the same spirit of exact and unimpassioned enquiry which has enabled science to solve so many problems.”