A lot of philosophers think that consciousness is what makes the mind/body problem interesting, perhaps because they think that consciousness is the only part of that problem that remains wholly philosophical. Other aspects of the mind are taken to be explicable by scientific means, even if explanatorily adequate theories of them remain to be specified.†
For most of the last century, and for all of the preceding ones, this attitude would have seemed strange, not because we took ourselves to understand how material beings could be conscious, but because we did not take ourselves to understand how they could be intelligent.
It was the discovery of computing that prompted our change of opinion: Already in the work Ada Lovelace, and very explicitly in the work of Alan Turing, it was supposed that human levels of intelligence had been made explicable by the discovery of ways in which matter can be arranged so that it performs computations. This was, and is, our best idea about how the mind might be naturalistically explained. It is now known to be more problematic than either Lovelace or Turing could have realized.
In order to see its problems, we need to look in some detail at the theory of computability. I do this in the first part of The Unexplained Intellect. (There are four parts of the book, but this first one is much the longest.)
In the next post — which will, I’m afraid, be rather a long one — I’ll remind the reader of computability theory’s power, with a view to indicating how it is that the discoveries of theoretical computer scientists place constraints on our understanding of what intelligence is, and of how it is possible. I’m hoping that later in the week we’ll have time to look at a theory of the metaphysics of mind that respects these constraints, by putting interactions between thinkers and their environments into a metaphysically foundational role, so that ‘epistemic encounters’ rather than knowledge states, are the most basic of mental phenomena. (The explication of this theory is the agenda of the book’s other three parts.)
[†: That consciousness is what makes the mind/body problem really interesting wasn’t quite the claim with which Nagel began ‘What is It Like to Be Bat?’. What Nagel wrote there was that consciousness is ‘what makes the mind-body problem really intractable’.]
