Sydney, born 1966

David Chalmers

Explaining what the brain does, how it discriminates, integrates and reports, leaves one question untouched: why is any of it accompanied by experience? A being physically identical to you, with no inner life at all, seems perfectly conceivable. If so, experience is something over and above the physical.

The view

Chalmers, who teaches at New York University and co-directs its Center for Mind, Brain and Consciousness, gave the field its central term. In a talk in Tucson in 1994 and a paper the following year, "Facing Up to the Problem of Consciousness", he distinguished the "easy problems" from the "hard problem". The easy problems, which are only easy by comparison, are explaining functions: how the brain discriminates stimuli, integrates information, focuses attention, controls behaviour and produces reports. The hard problem is explaining why the performance of these functions is accompanied by experience at all.

In The Conscious Mind (1996) he argued that no physical explanation can solve the hard problem, because physical explanations explain structure and function, and experience is something more. His positive view is naturalistic dualism: experience is a fundamental feature of the world, linked to physical processes by fundamental "psychophysical laws" still to be discovered. He has since shown growing sympathy for panpsychism.

The argument

Even when we have explained every function, a further question remains: why is it accompanied by experience? After Chalmers, "Facing Up to the Problem of Consciousness" (1995)

The most famous argument is the zombie argument. A philosophical zombie is a being physically identical to you, atom for atom, which behaves exactly as you do, says exactly what you say, including "I am conscious", but has no experience whatever. Chalmers argues: zombies are conceivable; what is conceivable is possible; if zombies are possible, then the physical facts do not fix the facts about consciousness; so physicalism is false. Compare the twins below.

Chalmers takes illusionism more seriously than most of its critics. In 2018 he proposed the meta-problem of consciousness: why do we think there is a hard problem? Why do people say experience is ineffable, private and impossible to explain? These are questions about behaviour, so they are "easy" problems in his sense, and any theory must answer them. He suggests that solving the meta-problem may shed light on the hard problem, and he grants that illusionism is the view that bets everything on that solution.

Where he meets Dennett

On the meta-problem, they share a research agenda. Both agree that our judgements about consciousness, our insistence that it is special, need explaining in physical terms, and both think that explanation will be a major scientific achievement. The two were friendly rivals for nearly thirty years.

Where they part

Here, as Dennett's 2016 essay makes plain, the disagreement is fundamental. Chalmers treats phenomenal consciousness as a datum; Dennett treats it as an intuition, like the conviction that the lady really was sawn in half. Dennett called the zombie argument a failure of imagination. If you really imagine a being that does everything you do, including reflecting on its own states, wondering at sunsets and writing books on the hard problem, you have imagined a conscious being. He coined the term zimbo for a zombie that monitors its own states and so says all the things we say about experience, and argued that we are zimboes. Press the third button: nothing distinguishes the twins, because there is nothing for the "inner light" to add.

Chalmers replies that this begs the question: the conceivability of zombies is exactly what shows functions are not enough. Dennett answers that conceivability, here, is the trick working on its audience.

See every view compared →

Further reading

• David J. Chalmers, "Facing Up to the Problem of Consciousness", Journal of Consciousness Studies 2 (1995).
• David J. Chalmers, The Conscious Mind: In Search of a Fundamental Theory (Oxford, 1996).
• David J. Chalmers, "The Meta-Problem of Consciousness", Journal of Consciousness Studies 25 (2018).
• Zombies, Stanford Encyclopedia of Philosophy.