The materialist assumption that consciousness is produced by the brain is on the decline. New theories, such as panpsychism, the idea that consciousness exists throughout the physical universe, are on the rise. But what about other alternatives? The notion that the brain acts as a reducing valve for consciousness was supported by the likes of Henri Bergson and Aldous Huxley, and could offer our best alternative to the materialist worldview, writes Paul Marshall. 

Consciousness is generated by the brain, isn’t it? Neuroscientists have commonly assumed so, and it is easy to understand why. Our everyday experiences are highly dependent on the brain and nervous system. For example, a stiff blow to the head knocks the living daylights out, as addled boxers can attest. Damage to the primary visual cortex at the rear of the brain shuts down conscious visual perception. Alterations to the brain’s neurotransmitter chemistry through illness or psychoactive drugs impacts on perception, cognition, and mood. Psychedelics, such as LSD and mescaline, can have particularly dramatic effects, ranging from superlative highs to abject lows.