JOHN POLKINGHORNE
John Polkinghorne is the retired president of Queens' College, Cambridge, CB3 9ET, UK. His latest book, published this month, is The God of Hope and the End of the World (Yale University Press, 2002). He was awarded the Templeton Prize for Progress in Religion on 14 March 2002.
Provocative ideas about science from a reductionist viewpoint.
Facing Up: Science and Its Cultural Adversaries
by Steven Weinberg
Harvard University Press: 2001. 304 pp. £17.95, $26
Collections of occasional writings do not always make good reading. In fact, they often seem little more than a lazy person's way of compiling a book. Steven Weinberg's latest publication, consisting of miscellaneous non-specialist pieces culled from his output over the past 17 years, fares a great deal better than most such offerings. There is certainly an unwelcome degree of over-lap and repetition between the essays, but Weinberg writes well and his clear style and strong opinions hold the reader`s attention. He says he has "a taste for controversy", and this punchy and provocative writing certainly bears this out.
Weinberg describes himself as "rationalist, reductionist, realist and devoutly secular", using all these adjectives in a very strong sense. I can only share one of these qualities with him: realist. Weinberg has been a vigorous participant in the so-called 'science wars', attacking strong accounts of the social formation of science and defending the claim that science achieves a verisimilitudinous understanding of what the physical world is actually like. He frequently asserts the equal reality of quarks and rocks. Weinberg acknowledges that reality is a hard concept to define, but he regards that as simply a technical problem for philosophers to solve, which should not give pause to scientists. I agree with him, as I do with his oft-repeated criticisms of the stance taken by Thomas Kuhn in these matters.
When it comes to reductionism, Weinberg takes a very hard line. He does not want to be a fundamental physics imperialist, in the sense of claiming that the practice of other disciplines could actually be reduced to corollaries of particle physics, but he does see his subject as providing an in-principle explanatory basis that needs no further augmentation. Weinberg calls this view "Newton's dream". While everyone in the scientific world would like to think that they have Sir Isaac on their side, this assignment of Newton to the hard reductionist position seems a highly curious judgement on a man who spent so much time on alchemy and the interpretation of prophecy, and who was a deeply religious person who believed in the causal powers of spirits (including, as he supposed, occasional corrections to the motions of the Solar System).
The acid test of reductionism is how it treats consciousness. Weinberg is very critical of ideas of emergence such as those defended by Philip Anderson with his well-known epigram 'More is different'. (Emergentists hold that a system will, as it grows more complex, display properties, such as consciousness, that cannot be explained in terms of the behaviour of its components.) Weinberg acknowledges that consciousness is very far from being understood, but so, he says, is the weather. Here he fails to recognize an important distinction between two kinds of emergence: the comparatively unproblematic (such as weather systems) and the problematic (such as mental systems). Weather systems involve exchanges of energy, and there is no insuperable difficulty in believing — to use a favourite Weinberg metaphor — that here the 'arrows of explanation' point down ultimately to basic physics. On the other hand, mental experiences — such as seeing red — appear to be qualitatively different from exchanges between neurons, let alone interactions between quarks.
Strong reductionism of the Weinberg kind is, in fact, a metaphysical assertion. If it is to be defended, this has to be on metaphysical grounds that go beyond the simply scientific. Although the judgement may seem odious, to imply otherwise is indeed an act of physics imperialism.
Another significant metaphysical issue is the status of values, such as ethical insights. Weinberg frequently affirms the importance of values, and he does not claim that they are something for which science itself can establish a basis. He sees them as human creations, by which we make for ourselves a little island of meaning in the hostile and meaningless Universe that surrounds us. There is a certain nobility in this bleak view, but I believe it to be mistaken. Our ethical intuition that abusing children is wrong is not simply something we have decided to assert. It is an actual fact about the complex reality within which we live, a form of knowledge whose origin is a question that requires very careful consideration. A true rationality has to take the reality of this kind of personal experience as seriously as it does science's impersonal encounter with the world.
This latter kind of reasoning is part of my motivation for being a religious believer. Weinberg is well known as an implacable opponent of religion. One of the essays in this volume arose from a conference to which we both contributed, which was convened to discuss whether there are any signs of inbuilt design in the Universe. Much of the argument related to the 'Anthropic Principle', the surprising recognition that a universe capable of generating carbon-based life has to satisfy very tight conditions on the strengths of the forces of nature operating within it. Weinberg refers to these matters from time to time, particularly noting the astonishingly tiny value (10–120 of its naturally expected strength) that the cosmological constant has to take in an anthropic world. He takes the multiverse way out, avoiding any whiff of theism by appealing to the highly speculative and metaphysically prodigal notion that our world is just, by chance, the anthropically fruitful member of a vast portfolio of diverse universes.
When Weinberg comments more generally on religion, the tone is highly polemical. He is right to draw attention to the horrors of religious wars and persecutions, for which a believer must feel shame and penitence, even if such terrible happenings are by no means the monopoly of religions. Yet that dark side is far from being the whole story, for much good and achievement (including initially modern science, some would claim) have also come out of religious belief. Weinberg rightly raises the issue of suffering, asking "how does free will account for cancer?" It does not, but an evolving world (theologically, a creation allowed to 'make itself') is one in which cellular mutations necessarily bring about not only new forms of life, but also malignancy.
This is an interesting book, with a lot to question and (I believe) disagree with, but is well worth reading. |
