In one way or another, skipping along the surface or lurking in the shadows, reductionism was part of last week’s series on consciousness, not to mention any number of other postings, recent and not so recent.
To some non-materialists, especially when it comes to the study of consciousness, “reductionism” is an evil methodology that takes the human out of humanity.
But there is reductionism, and then there is reductionism.
This distinction is central to “Reductionism Redux,” a 1995 essay republished in physicist Steven Weinberg’s 2001 collection, Facing Up: Science and its Cultural Adversaries. The book may be hard to find locally. Thanks to an online reseller, I managed to acquire a copy, a discard from the public library in Princeton, New Jersey.
In “Reductionism Redux,” Weinberg writes that “many science kibitzers and some scientists today speak of reductionism with a sneer, like postmodernists talking about modernism or historians about Whig historiography.” Considering the success of reductionism in creating the Standard Model in particle physics, Weinberg asks, “How has one of the great themes in intellectual history become so disreputable?”
His answer is that reductionism is misunderstood. There is what he calls “grand reductionism,” which seeks to explain nature in terms of “simple universal laws, to which all other scientific laws may in some sense be reduced.” And there is “petty reductionism,” the “much less interesting doctrine that things behave the way they do because of the properties of their constituents.”
In other words, Weinberg argues that “grand reductionism” is the search for the fundamental principles underlying everything in nature, while “petty reductionism” is the mechanistic view that if you know how something works, you know that thing entirely. In his view, the tendency to condemn all reductionism is a result of the erroneous conflation of the two kinds of reductionism.
Weinberg writes that “petty reductionism is not worth a fierce defense. Sometimes things can be explained by studying their constituents — sometimes not.” Just as it doesn’t make sense to talk about the hardness or temperature or the intelligence of “elementary” particles, it is also not possible to give a precise meaning to statements about particles being composed of other particles.
Weinberg asserts that “there is another distinction, one that almost no one mentions, between reductionism as a program for scientific research and reductionism as a view of nature.” The second kind of reductionism is the kind that Weinberg defends as “the search for the common source of all explanations.” He writes that “much of the criticism of reductionism is really only criticism of reductionism as a program for research.”
With this distinction clearly in place, Weinberg asserts the importance of “emergence,” the generation of new qualities and behaviours from the interaction of the elementary components of dynamic systems. I have argued before for this insight as the basis of an understanding of how something as complex and apparently personal as human consciousness can arise from “mere” matter. It is this insight that makes an entirely material yet not-just-materials mind possible. Without this insight, only the sterility of mere description or the fantasies of classical dualism remain. Weinberg acknowledges, and I agree, that consciousness is perhaps the most complex of the complex systems that can’t be described into full understanding.
Weinberg explains the emergence of consciousness with such admirable clarity that an unusually long citation is justified:
As we deal with more and more complicated systems, we see phenomena emerge from them that are much more interesting than a mountain of computer printout describing the motion of each particle in the system ever could be. Mind is a phenomenon that emerges from the biology of complicated animals, just as life is a phenomenon that emerges from the chemistry of complicated molecules. We are interested in whether George is happy to be out of jail in a way that is different from our interest in his nerve cells, and we are interested in his nerve cells in a way that is different from our interest in the electrons and protons and neutrons of which they are composed. But phenomena like mind and life do emerge. The rules they obey are not independent truths, but follow from scientific principles at a deeper level; apart from historical accidents that by definition cannot be explained, the nervous systems of George and his friends have evolved to what they are entirely because of the principles of macroscopic physics and chemistry, which in turn are what they are entirely because of the principles of the Standard Model of elementary particles.
I wish that I’d said that. I’ve tried to say that, but I’ve never managed to put the case for emergent complexity even half this well.
Consciousness is not a thing, like a drop of water. Consciousness is an event, like a flowing river. The brain is not consciousness. Consciousness is not the brain. Consciousness is an emergent property of the brain — and, for that matter, of the rest of the body, and of some of the environment.