This is my first ‘real’ blog post, and before I begin, I’d like to thank John for inviting me to contribute to this blog (and apologize for the fact that it’s taken me while to get around to doing so). Many thanks for giving me this opportunity!
I have recently published a review of Thomas Nagel’s “Mind and Cosmos” in Science (if you’re interested, it’s in Science, 339 (6125), p. 1277), and as the word limit there was very restrictive (and given how much stir the book has caused), I thought I’d take this opportunity to say a bit more about what I think about the book and, more importantly, to hear about what others here think about it.
Most of the reviews of Nagel’s book – especially those by philosophers – have been scathing. Now, as I said in my own review, I do think the book has several major flaws (more on those in a second). However, I am not sure it deserved quite the beating it received and I also don’t think it is the most interesting (let alone charitable) approach to focus solely on the negative points of a book in a review. So while I was (and remain) critical in my own approach, I also tried to bring out the positive points in the book.
Perhaps a few words on the negative points first. I think several aspects of the book are rather weak; for instance, the fact that in the chapter on ‘values’ Nagel simply assumes moral realism, without providing any argument for it. He also doesn’t do himself any favors when he combines (problematic) intuitions about the probability that consciousness and cognition could have evolved in the time span available with the philosophically rather more interesting issue of the (im-)possibility of reductionism. The former – which are regularly championed by proponents of ‘intelligent design’ (a movement which, despite his outspoken atheism, Nagel is sympathetic to, as he points out in the book) – don’t lead to strong arguments and can, I think, be rather easily dismissed (as indeed most of the reviews of his book have done). For one thing, we are notoriously bad at judging probabilities and aside from his ‘common sense’ intuition Nagel does not in fact provide any arguments for the view that the evolution of consciousness and cognition was unlikely. Moreover, even if this could be shown, it is unclear what follows from it (after all, to say that an event was unlikely to occur is not to say that it was impossible, and I don’t see why the former should lead one to reject an otherwise very strong theory, such as evolutionary theory). Further, his own sketch of an alternative, namely the introduction of teleological principles, remains unconvincing, not only because he doesn’t say much about how we are to think about these principles, but also because they don’t really seem to address what I ultimately take to be at the heart of his arguments – namely, the irreducibility of consciousness.
However, in focusing on the weaknesses, one fails to see that this main argument is actually very compelling, and that it needs a response (even if Nagel’s own response disappoints). So what is this argument? Well, it’s basically making the point that we are still lacking an understanding of the relation between the mind and brain. Consciousness doesn’t seem to be reducible to any functions fulfilled by processes in the brain (because it is conceivable that these functions could be fulfilled in the absence of any phenomenal qualities). If so, according to Nagel, not only do we have a mind-brain or mind-body problem, but we also have a problem when it comes to explaining the evolution of consciousness. This problem is very different from any considerations relating to probabilities of mutations etc. (even though, frustratingly, Nagel himself doesn’t do a very good job of keeping these two sets of problems apart). Rather, the problem consists in the fact that if consciousness necessarily remains outside the scope of the vocabulary of functionalism (or any other naturalistic theory), then it also remains outside the scope of evolutionary theory. While we might be able to explain why various cognitive functions that we take to be correlated with consciousness could have evolved, consciousness itself (due to the fact that it cannot be reduced to these functions) remains outside of the picture.
Now, none of this is particularly new or original, but given that we have recently witnessed several physicists (such as Stephen Hawking or Lawrence Krauss) argue that physics can explain everything, and given the general popularity of the view that there will ultimately be a ‘physical theory of everything’, I think Nagel is right to remind the general public (which is the target audience for this book) that there still is an ‘explanatory gap’ when it comes to consciousness, and that not everything can be explained in the terms of the physical sciences, after all. So, as someone who is generally sympathetic to ‘explanatory gap’ type arguments, I am sympathetic to this point (even though, unlike Nagel, I wouldn’t say that it implies that materialism is false, or, as he puts it, ‘almost certainly false’. In fact, I take it to be one of the other main flaws of the book that it doesn’t consider the possibility of a ‘non-reductive materialism’.) I found it somewhat surprising that, as far as I can tell, hardly any of the other reviews focused on this issue, and that instead everyone tried very hard to dismiss Nagel’s book as thoroughly as possible. I suspect this has something to do with the worry that the book will lend support to proponents of ‘intelligent design’, but I would find it problematic if because of this worry his arguments were given less credit than they deserve (especially since he makes it very clear that he is an atheist and that he isn’t looking for or trying to support some theological solution to the problem he raises).
Anyway, I am really curious to hear what you all make of this. What are your thoughts?