There is no such thing as ‘the’ hard problem of consciousness.  There is instead a large cluster of issues that need to be separated out and addressed in different ways.  Only a coordinated effort from different disciplines will allow us to make overall progress.

In my own field of philosophy, the most discussed problem concerns the apparent incompatibility between the existence of consciousness, and the world-view that many regard as non-negotiable from a scientific perspective, physicalism.

The incompatibility problem is an old one, and is redolent of religious ideas about the soul being distinct from the body. But it has been recast using the tools of contemporary philosophy and logic, which allow us to see with considerable clarity what physicalism is, what consciousness is, and what the arguments might be for their incompatibility.

How to solve it? The key thing is to focus on something so small and innocent that most people don’t notice it:  that when we think about the physical world we imagine we know what it’s like if not in detail then in outline.

Suppose we go along with that and take ourselves to know fully what the physical world is like.  Then we are forced into the familiar set of options most people find impossible:  either accept consciousness as a primitive addition to an otherwise physical universe, or deny its existence, or offer implausible oversimplified accounts of what it is.

But suppose instead we agree that our knowledge of the physical world is incomplete in all sorts of ways, including features connected to consciousness. Then the arguments for incompatibility lose their force.  If you don’t know fully what the physical world is like, you can’t argue that that consciousness has no place in it.

If you don’t know fully what the physical world is like, you can’t argue that that consciousness has no place in it.

From this point of view, there is no impediment to accepting both that we are conscious and that physicalism is true.  But the physicalism at issue here must be of a non-standard sort.  Physicalism is closely associated with contemporary science, but standard formulations of it incorporate something strangely pre-Darwinian: the rationalist view that the world is intelligible to us at least in outline.  A key lesson of the incompatibility problem is that to solve it we must reject rationalism of this sort, as well as any version of physicalism that entails it.

Many people accept that we are ignorant of certain features of the physical world, but will nevertheless resist the suggestion that this counts as a solution to the hard problem.   How can saying we are ignorant solve anything?

This forgets there are many different hard problems.  Ignorance matters when it comes to the arguments that consciousness is incompatible with physicalism.  But suppose you are interested instead in what the neural realisers of consciousness are, or how consciousness in a perception or memory influences its psychological role, or whether insects are conscious, or whether we can imaginatively identify with the conscious states of agents in the deep past or remote cultures.  No one thinks that reminders about our limitations bear directly on these and many other questions about consciousness.

No one thinks that reminders about our limitations bear directly on many other questions about consciousness.