Thomas Nagel is best known for his influential 1974 paper “What is it like to be a bat?”, in which he argued that phenomenological facts about consciousness are not reducible to physical facts. In this short book he updates his views on consciousness before extending his argument to facts about cognition and (objective) value. Like many before him, Nagel equates physicalism with materialism and objectivity with realism. Such moves may be innocuous but a few clarificatory words would not have gone amiss. His overall conclusion is that these three phenomena - consciousness, cognition and value - are obstacles to the increasingly popular assumption that there can be a physical theory of everything. One such theory, Nagel contends, is neo-Darwinism. In rejecting it he does not advocate any form of creationism but instead maintains that there is hope for a non- reductivist theory of everything that is compatible with atheism.
Philosophers who hold any one of the many views that Nagel rejects as unpromising (behaviourism, functionalism, eliminativism, panpsychism and so on) are unlikely to change their minds as a result of reading this book. As Nagel himself concedes, he is simply outlining a series of worries he has about the physicalist outlook rather than attempting to refute the latest version of each materialist theory on offer. Indeed, early on in Mind and Cosmos he writes that his aim “is not so much to argue against reductionism as to investigate the consequences of rejecting it”.
The reader might be excused for thinking that Nagel’s primary aim is to attempt to challenge the reductionist programme by offering an alternative theory of everything, one that we can hold on to should Nagel be right to think that reductionism will eventually have to be abandoned. However, the very next line reveals that this is not his strategy at all. Nagel is “concerned to present the problem rather than to propose a solution”, for he thinks that this is “all that can be done at this stage in the history of science”. By the author’s own lights, then, the book’s aim is neither to argue against reductionism nor to present an alternative solution to it. Once this is recognised, it is not hard to see that even if one is in full agreement with all that Nagel says, this is not a book that will live up to its title. It doesn’t even aim to do what it says on the tin.
The actual aim of the book is to show that (i) there are serious challenges to reductionism and (ii) if these cannot be met, we will need to undergo a serious paradigm shift before we can even attempt an alternative theory of everything. The second of these two claims assumes that there can be such a thing as the theory that accounts for everything in the Universe. I’m not sure why we should be so optimistically monistic but this is not a question that Nagel concerns himself with. What about the first claim? Nagel is right that physical reductionism is “an assumption governing the scientific project rather than a well-confirmed scientific hypothesis”. Moreover, it is not a purely empirical assumption but (at least in part) a metaphysical one.
Nagel’s argument against reductionism is built upon the complaint that it cannot render intelligible the likelihood of certain evolutionary occurrences relating to consciousness, cognition and value, whereas a non-materialist alternative might. But this move fails to distinguish between (i) explaining why X occurred and (ii) rendering the likelihood of X’s occurrence intelligible. This is problematic for two reasons. First, to render intelligible the likelihood of some occurrence is only to explain why something might have occurred, not why it actually did. Second, the conflation leaves no space for the view that unlikely occurrences may nonetheless be explained. A theory that explains why a rare event actually happened is far more powerful than one that (merely) renders intelligible why it was likely that it did.
This is an interesting and clearly written book by one of the most important philosophers alive today. It serves as an excellent introduction to debates about the power of scientific explanation. But given the author’s proven ability, it is a shame that greater care wasn’t taken to meet the book’s relatively modest theoretical goal.
Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature is Almost Certainly False
By Thomas Nagel. Oxford University Press. 144pp, £15.99. ISBN 9780199919758. Published 22 November 2012