The Hard Problem is a category mistake
What consciousness and vital force have in common and why it matters
There is a moment in every philosophy classroom, roughly ten minutes after David Chalmers’ “hard problem of consciousness” has been introduced, when students lean back with a look of settled satisfaction. Of course there is something that scientific explanation cannot reach. Of course the felt redness of red, the specific ache of longing, the taste of coffee on a Tuesday morning – of course these resist the cold vocabulary of neurons and action potentials. Science can tell you what happens, but it cannot tell you what it is like. Case closed.
I want to suggest that this satisfaction is premature, and that what feels like a profound philosophical discovery is actually a category mistake, a confusion between two entirely different kinds of things dressed up as a metaphysical gap.
Two types of not-having
Let me start with a bicycle. Imagine someone who has read every book ever written about cycling: the biomechanics of balance, the physics of angular momentum, the history of the derailleur, the optimal cadence for hill climbing. This person has, let us stipulate, complete theoretical knowledge of what cycling is and how it works. Now put them on a bicycle. They will (likely) fall over.
Does this mean their theoretical knowledge was incomplete? Of course not. It means that knowing-about something and doing something are different kinds of achievement (in philosophy these are often referred to as knowing-that and knowing-how, a distinction introduced by Gilbert Ryle). There is no deficiency in the theory. The theory wasn’t trying to be a skill, it was trying to be an explanation, and as an explanation it is perfectly adequate, and complete. The gap between the textbook and the bicycle path is not an explanatory gap, it is a gap between explanation and performance, between two fundamentally different registers of human engagement with the world.
Chalmers’s hard problem of consciousness has exactly this structure, and it inherits exactly this confusion. The claim, stripped to its essentials, is this: even a complete neuroscientific account of conscious experience – every neuron, every connection, every electrochemical cascade mapped in full – would not amount to the experience itself. You could know everything there is to know about what happens in a brain when someone sees red and still not know what red looks like. Therefore, the scientific explanation is allegedly somehow deficient, there is something left over that it cannot reach: the “qualia,” the felt quality of experience, what philosophers call phenomenal consciousness.
But notice: of course a complete description of red-perception is not the same thing as seeing red. A description of anything is not the same thing as the thing described. A complete chemical account of coffee is not the smell of coffee. A comprehensive seismological description of an earthquake is not the terror of feeling the ground move. This is not a special problem about consciousness, it is just what descriptions are. They are not the things they describe. The map, if you will, is not the territory, and to confuse the two is a serious error. To treat such a “gap” as evidence that the description is incomplete is to commit what Ryle called a category mistake: demanding that an explanation do something that explanations are not in the business of doing.
The hard problem, in other words, gets its apparent force from conflating two questions that should be kept strictly apart: what is happening when someone has an experience? (a scientific question) and what is it like to have that experience? (a question that can only be answered by having it). The first is in the business of explanation, the second is in the business of acquaintance. A complete answer to the first question will never constitute an answer to the second, not because science is limited, but because those are simply different kinds of questions.
Conceivability is not possibility
Chalmers’s most famous argument for the hard problem involves what he calls “philosophical zombies” (or p-zombies). These are hypothetical beings physically and behaviorally identical to humans in every respect but lacking any inner experience whatsoever. The lights are on, in every functional sense, but nobody is home. Chalmers argues that such beings are conceivable, that conceivability is good enough evidence for possibility, and that their possibility shows that consciousness is something over and above physical organization.
The first thing to say about this argument is that conceivability is extraordinarily weak evidence for possibility. People conceived of squaring the circle for centuries, that is, of constructing a square with the same area as a given circle using compass and straightedge alone. It was only in 1882 that Ferdinand von Lindemann proved this to be impossible, by demonstrating that π is transcendental. The conceivability of the construction misled generations of careful mathematicians.
