Remarkable Facts: Ending Science As We Know It
October 18, 2012
Thomas Nagel, a distinguished philosopher at NYU, is well known for his critique of “materialistic reductionism” as an account of the mind-body relationship. In his new and far-reaching book Mind and Cosmos, Nagel extends his attack on materialistic reductionism—which he describes as the thesis that physics provides a complete explanation of everything—well beyond the mind-body problem. He argues that evolutionary biology is fundamentally flawed and that physics also needs to be rethought—that we need a new way to do science.
Nagel’s new way is teleological—scientific explanations need to invoke goals, not just mechanistic causes. The conventional story of the emergence of modern science maintains that Galileo and Newton forever banished Aristotle’s teleology. So Mind and Cosmos is an audacious book, bucking the tide. Nagel acknowledges that he has no teleological theory of his own to offer. His job, as he sees it, is to point to a need; creative scientists, he hopes, will do the heavy lifting.
Nagel’s rejection of materialistic reductionism does not stem from religious conviction. He says that he doesn’t have a religious bone in his body. The new, teleological science he wants is naturalistic, not supernaturalistic. This point needs to be remembered, given that the book begins with kind words for proponents of intelligent design. Nagel applauds them for identifying problems in evolutionary theory, but he does not endorse their solution.
Nagel’s main goal in this book is not to argue against materialistic reductionism, but to explore the consequences of its being false. He has argued against the -ism elsewhere, and those who know their Nagel will be able to fill in the details. But new readers may be puzzled, so a little backstory may help.
In his famous 1974 article “What is it like to be a bat?” Nagel argues that current science lacks the concepts that would allow us to understand how subjective experience is possible. Present-day science can give us information about the bat’s brain, but it cannot answer the titular question of Nagel’s article—what is it like, how does it feel from the inside, to be a bat? Nagel chooses bats as his example because they have a sensory system (echolocation) that we lack. This choice makes the problem vivid, but Nagel thinks the difficulty arises at home: each of us knows what sugar tastes like, yet current science lacks the vocabulary to understand and explain what that peculiar subjective experience is like. Nagel is cautious in the bat article; he hopes that a future materialistic science might be able to do better.
In Mind and Cosmos, Nagel holds that materialism can’t deliver the goods. Drawing on his bolder and more recent paper “The Psychophysical Nexus,” he now says that materialistic reductionism is false, not that we currently don’t understand how it could be true. For Nagel, perception and other psychological processes involve irreducibly subjective facts; important aspects of the mind are, therefore, forever beyond the reach of physical explanation.
This position is compatible with many doctrines that are associated with materialism. For example, Nagel doesn’t gainsay the slogan “no difference without a physical difference”—if you and I have different psychological properties, then we must be physically different. Indeed, Nagel’s position is even compatible with the idea that every mental property is identical with some physical property—for example, it may be that being in pain and being in some neurophysiological state X are identical in the same way that being made of water and being made of H2O are identical properties. The problem, Nagel thinks, is that this identity claim, if true, cannot in principle be explained by physics. Mind and Cosmos begins with the thesis that materialistic reductionism hits a roadblock with the mind-body problem, but there are others ahead. Although Nagel has more to say about the mind-body problem than I have just outlined, the most novel part of his book, and my focus, lies elsewhere.
Nagel believes that evolutionary biology is in trouble, but what sort of trouble is it in? There are two possibilities. Evolutionary theory could be in trouble just because it is committed to materialistic reductionism; if so, the theory would be perfectly okay if it dropped that commitment. Understood in this way, it’s the philosophy that has gone wrong, not the biology. But much of what Nagel says is not in this vein. He thinks that the biology itself is flawed. Even without a commitment to materialistic reductionism, the theory would be in bad shape. For Nagel, the combination of evolutionary theory and materialistic reductionism is false, while evolutionary theory taken on its own (without the philosophical add-on) is incomplete. Incompleteness means that the theory cannot fully explain important biological events.
For Nagel, important aspects of the mind are forever beyond the reach of physical explanation.
Here I want to consider two criticisms that Nagel makes of evolutionary theory. The first concerns probability, the second, ethics. Neither criticism depends on the idea that evolutionary theory is committed to materialistic reductionism.
Nagel thinks that adequate explanations of the origins of life, intelligence, and consciousness must show that those events had a “significant likelihood” of occurring: these origins must be shown to be “unsurprising if not inevitable.” A complete account of consciousness must show that consciousness was “something to be expected.” Nagel thinks that evolutionary theory as we now have it fails in this regard, so it needs to be supplemented.
Nagel doesn’t impose this condition of adequate explanation on all the events that science might address. He is prepared to live with the fact that some events are just flukes or accidents or improbable coincidences. For example, it may just be an improbable coincidence that in the mid-1980s Evelyn Marie Adams won the New Jersey lottery twice in the span of four months. But the existence of life, intelligence, and consciousness are not in the same category. Why do Nagel’s standards go up when he contemplates facts that he deems “remarkable”? Maybe the answer falls under what Nagel refers to, in a different context, as his “ungrounded intellectual preference.” It isn’t theistic conviction that is doing the work here, but rather Nagel’s faith that the remarkable facts he mentions must be “intelligible,” where intelligibility requires that these facts had a significant probability of being true.
My philosophical feelings diverge from Nagel’s. I think that Beethoven’s existence is remarkable, but I regard it as a fluke. He could easily have failed to exist. Indeed, my jaded complacency about Beethoven scales up. I don’t think that life, intelligence, and consciousness had to be in the cards from the universe’s beginning. I am happy to leave this question to the scientists. If they tell me that these events were improbable, I do not shake my head and insist that the scientists must be missing something. There is no such must. Something can be both remarkable and improbable…