The Question of Consciousness

Consciousness is the most familiar thing in the world and the least understood. Every other scientific problem — the structure of matter, the origin of life, the mechanisms of heredity — concerns something observed from the outside. The problem of consciousness is the problem of explaining how there comes to be an inside at all: how physical processes in the brain give rise to subjective experience, to the fact that there is something it is like to be the person having them.

The philosopher David Chalmers has called this the hard problem of consciousness, distinguishing it from a range of easier problems — the explanation of attention, memory, learning, emotional response — which are difficult but in principle tractable by standard scientific methods. The hard problem is different in kind. Even a complete functional account of all brain processes would leave open the question of why those processes are accompanied by experience rather than proceeding in the dark.

The responses to this problem divide broadly into those that accept it as a genuine explanatory gap and those that argue it is a pseudo-problem produced by conceptual confusion. The physicalist holds that consciousness will eventually be explained in terms of physical processes, and that the appearance of an unbridgeable gap reflects our current ignorance rather than a fundamental feature of the world. The dualist holds that consciousness is genuinely irreducible to physical terms. The illusionist holds that consciousness, as ordinarily conceived — as involving genuine subjective experience — is an illusion; what exists is the functional organisation, which generates the representation of experience without the experience itself.

None of these positions is obviously correct, and the debate has not substantially converged in the decades since Chalmers named the problem. What is perhaps most significant about it is not its current state but what it reveals about the limits of scientific explanation as currently understood. The methods that have proven so powerful in explaining the physical world — reduction to constituent parts, mathematical modelling, experimental test — seem to leave something essential about experience untouched.

Whether this is a temporary limitation or a structural one is among the more important open questions in philosophy and science. The answer, when it comes, will require either a revision of how we understand consciousness or a revision of how we understand explanation.