About Time We Retire Physicalism
by Mridul
Our knowing that we're conscious by itself proves that physicalism is false. This is because physicalism entails that consciousness has no purpose, that it's only an epiphenomenon — like steam out of the chimneys of a steam engine. But we can show that consciousness can cause things, contradicting the implication of physicalism, rendering it broken.
The world follows physical laws, and so the character of all higher-order systems, including brains, is fully determined by the activities of their constituent particles. There is no wiggle room. No emergent phenomenon, no high-level abstraction of complex systems, has extra causal power over and above that of the matter that they're instantiated in.
No story about how neurons passing electrical signals between each other to form representations of images or audio can explain how any such goings-on would produce a felt, subjective experience of colours and music — what Chalmers called the Hard Problem of consciousness (which might be more appropriately called the Unbridgeable Gap).
Consciousness, in the physicalist perspective, can be thought of as some emergent property of matter which comes into being when matter organises itself in some particular way — such as a human brain. We don't know why or how, but it seems to be coming along for the ride at some point. Nevertheless, since all our behaviours down to our minor twitches and occasional squirms constitute a physical system, it follows that consciousness has no apparent role to play here. Everything is already accounted for by the particles that are acting as the brain. Consciousness merely hovers along without any causal power.
If that were so, however, there would be no way for a brain to know that it's conscious. As consciousness comes into being while a brain does the right sort of whatever, the brain itself is unaffected. It carries on interpreting sensory inputs, modelling the world, and making decisions, all the while being unaware that a mysterious entity mirroring its structures has appeared in the world. If consciousness somehow were to interfere with the brain, even as little as signalling its own existence, it would literally break the laws of physics.
Physicalism implies we can never know we're conscious, yet we constantly talk about the things we see, the way we feel, and the ideas we're thinking of, including ones about consciousness itself. Physicalism is, therefore, completely absurd.
How are our mouths moving to form words that reference a conscious experience? How can I say that "I'm seeing red", while seeing redness in my visual field, without there being a causal link between the seeing and the saying? Per the physicalist, the experience of seeing red, which preceded my speaking those words, has nothing to do with my speech. It's only the neural correlates of this experience that are doing any work. In principle, all of that could have worked in the dark, unconsciously, and it wouldn't have made a difference, one way or the other, to the contents of my speech.
How, then, do the words I'm speaking so accurately represent the reality that a red was indeed seen by me? Is it only pure coincidence? A miracle perhaps? The physicalist has no answer. And it's easy to see why.