Friday, December 7, 2012
Nagel on Mind & Cosmos
More notes on Nagel’s Mind and Cosmos: Why the Materialist Neo-Darwinian Conception of Nature Is Almost Certainly False. Nagel uses the terms “materialism” and “materialist” where I would use “physicalism” and “physicalist”. So far I think my usage is vindicated.
The word materialism is more reductionist in implication that those who use it ordinarily intend. It focuses the mind on the concept of material at the expense of all the non-material aspects of physical nature such as form and energy. Nagel uses the term to encompass all physical explanations.
To take an example, consider a beaker of water sitting over a gas flame. The beaker is material and the water is material. But the water is being heated without any change in the molecular constituents of the water and the molecules of glass hold the water in place only because they are in a certain shape. Shatter the glass and the same material will produce a distinct set of phenomena.
Again, I prefer physicalism because I think that the physical can be defined (as Nagel neglects to define it) as the measurable. I am only on Chapter 3, making notes as I go, but it already seems clear that the title of the book is both misleadingly provocative and understated. Nagel is not arguing that “the materialist Neo-Darwinian Conception of Nature is false.” So far, he doesn’t seem to quarrel with any part of the Darwinian synthesis.
He is claiming that physicalist science is necessarily incomplete and (a more radical claim) that a complete account of nature is possible. He has made it pretty clear so far that he is not going offer any such account but intends to say what kind of account would meet the purpose.
Nagel does not flirt with dualism, let alone theism. He thinks that the brain does produce the conscious mind and that human brains and consciousness are products of evolution. But he thinks that physical explanations alone cannot for consciousness.
I think that that is clearly correct, at least in the meantime. He considers various physicalist approaches to the mind/body problem. Behaviorists attempted to reduce terms for mental states to terms for behavioral states, so that “pain” meant nothing more nor less than saying “ouch!” That is unsatisfactory, as anyone knows who has heard the one about the two behaviorists who have just finished making love. “That was good for you,” says the one; “how was it for me?” Obviously, first person experience is a better guide to one’s own mental states than any behavior one might display.
Identify theorists argue that mental states are identical with brain states, so that any mental state Ψ is to some physical (brain) state Φ as water is to H2O. This analogy fails because H2O is a sufficient explanation for water in all its forms whereas there is nothing in a measurable brain state that would lead you to infer the existence of consciousness if you did not already know that the latter was a fact.
I would add, though Nagel skips past it, that the same is true of functionalist accounts of mind. Minds are obviously functional. They process information in ways that allow us to navigate around obstacles and find food and mates. However, as the infamous zombie problem indicates, there is no obvious reason why a mind has to involve consciousness in order to function properly. If one of those robot vacuum cleaners can navigate around table legs without being aware of them, what need have I for all my heartbreaks?
Consciousness seems, at present, radically private. My body temperature, brain states, and behavior are measureable and therefore physical. No one can measure the passion that a photo of my infant daughter produces in me every time I look at it. It seems logically possible that we will someday have a qualiameter that can measure inner experience more or less directly. Until then, we cannot have a completely physical account of nature.
Nagel insists rightly that the fact of consciousness has implications beyond biology. If indeed physical processes produced conscious creatures over the course of evolutionary history, then the potential for consciousness was present in dumb matter from the beginning. There is more to heaven and earth than could be guessed from all previous physics and chemistry.