Rationality or consciousness is itself a ratio or proportion among the sensuous components of experience, and is not something added to such sense experience. Subrational beings have no means of achieving such a ratio or proportion in their sense lives but are wired for fixed wave lengths, as it were, having infallibility in their own area of experience. Consciousness, complex and subtle, can be impaired or ended by a mere stepping-up or dimming-down of any one sense intensity, which is the procedure in hypnosis. And the intensification of one sense by a new medium can hypnotize an entire community.
Marshall McLuhan, Understanding Media: The Extensions of Man
consciousness, rationality