Thomas Nagel, Mind and Cosmos: Why the Materalist Neo-Darwinian Conception of Nature is Almost Certainly False, (Oxford, Oxford University Press, 2012).
Thomas Nagel was born in Belgrade so I can’t help but have a certain affection for his writing, even though I recognise that none other reason can stand as more vulgar.
Nagel recently wrote two review articles, one for the London Review of Books and the other for the New York Review of Books that are well worth reading. The first is on terrorism, and Nagel makes interesting points regarding the rationality of terrorists, and the ethically odious nature of the practise. The second is a splendid review of a book on the enlightenment and the rise of modern philosophy. The review is splendid, but I doubt whether the same can be said of the book.
I would like to discuss Nagel’s reviews, however I shall leave that for another time.
What interests me here is his argument against materialism, or better still physicalism, in his recent, controversial, text Mind and Cosmos
Nagel observes (p13),
The conflict between scientific naturalism and various forms of antireductionism is a staple of recent philosophy. On one side there is the hope that everything can be accounted for at the most basic level by the physical sciences, extended to include biology. On the other side there are doubts about whether the reality of such features of our world as consciousness, intentionality, meaning, purpose, thought, and value can be accommodated in a universe consisting at the most basic level only of physical facts – facts, however sophisticated, of the kind revealed by the physical sciences.
Nagel declares himself to be on the side of the doubters. He goes on (pp14-15),
So what explains the existence of organisms like us must also explain the existence of mind. But if the mental is not itself merely physical, it cannot be fully explained by physical science either. If evolutionary biology is a physical theory – as it is generally taken to be – then it cannot account for the appearance of consciousness and of other phenomena that are not physically reducible. So if mind is a product of biological evolution – if organisms with mental life are not miraculous anomalies but an integral part of nature – then biology cannot be a purely physical science. The possibility opens up of a pervasive conception of the natural order very different from materialism – one that makes mind central, rather than a side effect of physical law.
He states that materialism entails reductionism (p14),
Materialism requires reductionism; therefore the failure of reductionism requires an alternative to materialism.
Nagel is almost certainly false. It is useful to illustrate this, firstly, with appeal to history most especially the history of our theories of matter. What historians of science refer to as “the chemical revolution” was the attempt to identify and explain as many chemical reactions as possible with as few assumptions as possible, but chemical theory, for a very long time, was largely phenomenal rather than physical.
Toulmin and Goodfield in their history of theories of matter, The Architecture of Matter, observe that as late as the 1860s
Since the absolute sizes of the hypothetical atoms could not be known, chemical atomism could legitimately be interpreted in either of two ways- ‘realist’ or ‘phenomenalist.’ One could read it as committing one to an outright assertion that matter is in reality made up of minute corpuscles; or, alternatively, one could interpret it more cautiously as an intellectual construction in which matter was depicted as if it were made up of minute corpuscles. It made no difference to chemistry which way one took it, and as late as 1900 a minority of scientists still took the more cautious view – including one winner of the Nobel Prize for Chemistry.
Cobb and Goldwhite in their history of chemistry, Creations of Fire, put the matter nicely
So there was Dalton with his atoms, Gay-Lussac with his combining volumes, and Avogadro with his molecules and they could not get together.
A Nagelian of the era might have declared that the physicalist view of the world is almost certainly wrong for chemistry could not be reduced to physics. If physics could not account for facts of matter such as chemical laws, what hope then for physics to explain intentionality and the like?
Indeed, chemistry was never reduced to physics. Rather what happened was that physics had to undergo a conceptual revolution, a revolution that went to the core of our understanding of the physical, before chemistry could be unified with physics.
As Cobb and Goldwhite relate
The electrochemical theories of the 1800s explained how opposite electrical charges held some species together, but they failed -as did every other theory – to explain the existence of the simplest compound, molecular hydrogen, formed from two identical atoms of hydrogen. Without an explanation, it was impossible to make further predictions except one: another revolution was needed. This time the revolution was much quicker in coming. It arrived with the new century, the 1900s: the quantum revolution. Quantum theory, the basis of the quantum revolution, was the result of a marriage of efforts: physicists worked with chemists to gain an understanding of radioactivity, reactivity, and the structure of the atom.
One can readily appreciate from the foregoing that chemistry was not reduced to physics.
Something similar can be discerned at work in the sciences of the mind. It is the mind, as noted, to which Nagel grants ontological primacy. The first cognitive revolution, associated with the scientific revolution, made important advances in our understanding of the mind but it was not able to advance for lack of intellectual armoury.
That came with the development of theories of computability and advances in discrete mathematics associated with Frege, Russell, Godel, Turing, Church and so on. The advent of such tools enabled the progression of the cognitive sciences which takes cognitive processes to involve the operation of computational processes upon mental representations. The early forbears may have had the concept of mental representation, but notions of computability advanced enough to develop a cognitive science were not available.
Cognitive science is not accounted for in terms of physics, say quantum physics. There is no quantum mechanical explanation, say, of the minimalist programme in linguistics. This is true of the mental phenomena that Nagel outlines, to be sure, but this is true of physics as we currently understand it.
Physics is behind the cognitive sciences in much the same fashion that it was behind chemistry. For it to catch up, as it were, through an act of unification, not reduction, might well require a further conceptual revolution in our understanding of the physical. If so this means the claims Nagel makes regarding physicalism are surely wrong.
The methodological physicalist would not and need not be concerned with reducing mental properties to physical law, even though there exists a hazy understanding that somehow natural phenomena can in principle be accounted for in terms of physical law. As with the chemists of yesteryear the task is to proceed with the cognitive revolution and the scientific study of the mind using tools currently at hand, leaving the matter of unification with physics to future generations.
The fact that mental properties cannot be explained in terms of current physical law does not mean that it cannot be accounted for in physical terms in principle for current physics is not final physics no more than the classical physics of the 19th century was final physics.
I believe that this argument applies to other philosophical doctrines, such as eliminative materialism and neurophilosophy. With the former the impulse is to eliminate certain of mental phenomena, say consciousness or free will, on grounds that they cannot be reduced to, or explained by, current physics. Such a view tends to assume that current physics exhausts the range of possible physical law, so being physicalists we eliminate out of our ontological categories what current physical theory cannot explain. The same applies to neurophilosophy, whose inflated claims have been well challenged by Colin McGinn among others.
I also kind of think that one of the main faults of logical positivism, which was a type of philosophical naturalism par excellence (the empiricist epistemology flowed from a physicalist ontology, I feel) was that it attempted to develop a comprehensive picture of the world based on partial and limited physics. This one cannot do. Intellectual humility demands no less.
What is interesting about the two views above, that is of eliminative materialism and neurophilosophy, is that to oppose them is to be dismissed as being anti naturalistic, sometimes in quite vociferous fashion, yet I can’t help but feel that the position espoused here is the most sensible for a naturalist or physicalist to adopt.
At any rate, Nagel is almost certainly wrong to proclaim that failure to reduce this or that category or natural process, evolution say, to physical theory demonstrates that physicalism is wrong or that physicalism entails reductionism and so therefore the failure of reduction demonstrates the fallacy of physicalism.