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200 theories · 13 subcategories

Materialism: theories of consciousness

Consciousness is entirely physical. Every experience is produced by brains and bodies, and ultimately by the particles and fields of physics, with nothing nonphysical left over.

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Materialism holds that consciousness is a product of physical systems, chiefly biological brains, and that nothing nonphysical is involved. It is the working assumption of most neuroscientists, and their evidence is concrete. Damage part of the brain and part of experience disappears; stimulate it and experience changes. In the 2020 PhilPapers survey, 51.9 percent of professional philosophers accepted or leaned toward physicalism.

Most materialist theories aim to reduce mental states to physical ones, explaining a feeling by the brain processes that carry it. Reduction is optional, though. A theory qualifies as long as it admits nothing nonphysical. Some views identify experiences with brain states, some with functional roles, and some argue that experience as we picture it does not exist at all.

Its thirteen subcategories are Philosophical, Eliminative/Illusionism, Mind-Brain Identity, Neurobiological, Electromagnetic, Computational, Homeostatic, Embodied, Relational, First-Order, Higher-Order, Language and Phylogenetic. They run from U. T. Place and J. J. C. Smart’s claim that mental states are brain states, through Crick and Koch’s search for the neural correlates of consciousness and Baars and Dehaene’s Global Workspace Theory, to Paul and Patricia Churchland’s eliminativism and the illusionism of Daniel Dennett and Keith Frankish, which treats our sense of an inner felt quality as an introspective trick.

The central problem is what Joseph Levine called the explanatory gap. A complete account of which neurons fire, and why, still seems to leave open why that activity feels like anything from the inside, the puzzle David Chalmers named the hard problem. By Chalmers’s count, materialists answer in three ways. Some deny the gap exists, some accept a permanent gap in what we can know while denying any gap in what exists, and some expect future science to close it.

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Philosophical 15

Philosophical materialism holds that the mind is wholly a product of physical matter. Its theories set out the principles, definitions, and arguments that any materialist account of consciousness needs before the science begins.

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Eliminative/Illusionism 12

Eliminativists and illusionists hold that the private, felt qualities of experience, often called qualia, are not real features of the world. The brain represents itself as having them, and that representation is what science must explain.

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Mind-Brain Identity 11

Mind-brain identity theory holds that every conscious experience is literally a brain process, one event described in two ways, just as lightning is an electrical discharge and water is H₂O.

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Neurobiological 29

Neurobiological theories hold that consciousness is produced by nervous tissue and nothing else. They try to pin down which neurons, circuits, rhythms, or brain regions generate it.

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Electromagnetic 13

Electromagnetic field theories hold that consciousness is, or arises from, the electromagnetic field generated by the brain's combined neural currents, a single physical field that could bind scattered neural activity into one experience.

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Computational 22

Computational theories hold that consciousness is a kind of information processing. What counts is the computation a system performs and the roles its states play, so the right program could in principle be conscious in silicon as well as in neurons.

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Homeostatic 19

Homeostatic and affective theories hold that consciousness grows out of the brain's work of keeping the body alive and stable, and that feeling, the felt sense of how the organism is doing, is its most basic form.

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Embodied 12

Embodied and enactive theories hold that consciousness belongs to a whole living body acting in its world. Experience is shaped by bodily form, movement, and interaction, and cannot be fully located in the brain alone.

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Relational 14

Relational theories hold that consciousness is a relation, arising between subject and object, organism and environment, or brain and world, and so cannot be found in the brain's circuits taken by themselves.

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First-Order 9

First-order theories hold that a mental state is conscious because of what it represents about the world. The felt character of an experience, such as seeing red, is the content of that representation, with no further awareness of the state required.

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Higher-Order 14

Higher-order theories hold that a mental state is conscious when the mind represents it, through a thought or inner perception about that state. Consciousness is a representation of a representation.

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Language 14

Language theories examine how consciousness and language depend on each other. Few hold that language creates raw experience, but many argue that it shapes human self-awareness, inner speech, and the reflective consciousness that thinks about itself.

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Phylogenetic 16

Phylogenetic theories explain consciousness through evolution. They ask when and in which animals experience first appeared, what survival advantage it gave, and how simple sensing grew into the minds of mammals, birds, and octopuses.

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