Who Wrote the Book of Nature?

by Andrew Crumey

Review of The Big Picture by Sean Carroll. The Wall Street Journal, May 13, 2016.

As a boy, Sean Carroll enjoyed going to church in his hometown of Trenton, New Jersey. He liked "the hymns, the imposing wood pews... the mysteries and the doctrine" [p495]. He also liked the pancakes afterwards. But as he grew older, something changed. "My transformation to atheism wasn't dramatic or life-shaking; it just kind of crept up on me." [p495-6] Carroll is now professor of theoretical physics at the California Institute of Technology, and his book - grandly subtitled "on the origins of life, meaning, and the universe itself" - is a manifesto that will divide reader opinion along familiar party lines. But unlike some in the science-versus-religion debate (most notably Richard Dawkins), Carroll is not on a mission to show that believing in God is as futile as writing letters to Santa Claus. Never hectoring, always tolerant, Carroll presents a seductively attractive picture of a universe whose ultimate laws lie within our grasp. He might even make a few converts. So why do I, an atheist and physicist myself, find so much of what he says frankly fishy?

Carroll describes his philosophy as "poetic naturalism", a term that immediately seems set to lure in those of a syncretic disposition who see art and science as a unity. He quotes the poet Muriel Rukeyser, "The universe is made of stories, not atoms", [p21] which sounds like the sort of poststructuralist orthodoxy that long held sway in fields of academia remote from Carroll's own. But he inverts Rukeyser's maxim. The universe is made of "stuff"; not atoms, but something more fundamental. That's the "naturalism" part. We tell stories about the stuff: that's the "poetic" aspect. So really, a better term might be "prosaic naturalism", or even just good old-fashioned materialism.

"What is the fundamental nature of reality?" Carroll asks [p11]. "Philosophers call this the question of ontology - the study of the basic structure of the world." Alert students of Metaphysics 101 will at this point raise a hand to say that ontology is instead the question of what "being" means. For most of us, the study of the basic structure of the world is called theoretical physics. The question of how exactly that superbly successful science relates to "the fundamental nature of reality" is left begging.

And what about all those "stories" we tell? Since they're about real stuff, some are presumably more true than others. Carroll invokes the metaphor of a "planet of belief": a body of knowledge held together by the "gravitational pull" of mutual consistency [p123]. According to Carroll, "we should be constantly testing and probing our planets of belief for inconsistencies and structural deficiencies". [p124] Of course, "The real problem is that we can imagine more than one stable planet", [p124] so how do we choose which to live on? A "habitable" planet, says Carroll, "necessarily includes some shared convictions about evidence and rationality, as well as the actual information we have gathered about the world" [p126]. Put more succinctly, his position is that science is the only authentic access to genuine knowledge about reality, and science is a hierarchy of "stories" with theoretical physics sitting at the foundation.

So what, then, is the basic "stuff" about which all consistent, coherent stories are ultimately told? It is not, of course, the atoms that were long ago smashed into smaller pieces, nor even the quarks and leptons whose speeding tracks are spotted in particle accelerators. It is instead the quantum fields whose vibrations we detect as matter and radiation. And here it is I who must raise a hand from the back of the class and ask: is a quantum field "stuff" or "story"? An anecdote that may or may not be true says that the great theorist Paul Dirac was once asked what an electron was, so he wrote an equation on the blackboard, pointed to a symbol in it, and said, "That's an electron". This is essentially Carroll's view, and as the anecdote shows, it is of noble lineage. But it remains debatable, and Carroll's evasion of that issue undermines the version of materialism he takes for granted in his "poetic naturalism".

To an extent, his idea of real stuff and stories about stuff resembles the work of the French philosopher Alain Badiou, who has sought to ground materialism on a quasi-mathematical basis, presenting ontology ("being") as set theory, and phenomenology ("appearance") in terms of a considerably more abstruse framework. Badiou's protégé Quentin Meillassoux has also developed a highly sophisticated approach to what has been termed "speculative materialism". Carroll's pre-Kantian poetic naturalism is naive by comparison, in a technical and not pejorative sense. The hardest part of philosophy is understanding the questions, and Carroll knows that what his readers are looking for is answers, which he presents with admirable clarity.

What he gives us in this book, once we accept the empiricist ground rules, is a highly enjoyable tour through a very wide range of topics. Theoretical physics takes centre stage, but there are also excursions into evolution, consciousness, and the ultimate fate of the universe. The tone is unfailingly engaging; even if you don't agree with what he says, you are unlikely to be enraged by such an urbane lecturer, more likely enthralled. Still, no matter how basically sympathetic I am towards his position, I can't help feeling that in his opposition to religion he's really shooting at straw men. "For the sake of keeping things simple," he writes, "let's divide all the possible ways of thinking about God into just two categories: theism (God exists) and atheism (no he doesn't)... And for the sake of being definite, let's imagine that we're talking about God as a person, as some kind of enormously powerful being who is interested in the lives of humans." [p158] That leaves out a lot of possibilities. Carroll appeals to evidence, but interestingly expresses faith in the speculative "many worlds" interpretation of quantum theory. He doesn't believe in God, but presumably believes in the actual existence of another universe containing another Sean Carroll who does. I wonder what sort of book his other self would write?