Has Physics Lost Its Way?

Nonfiction THE DREAM UNIVERSE How Fundamental Physics Lost Its Way By David Lindley The title of David Lindley’s new book, “The Dream Universe,” may be unprepossessing, but his subtitle — “How Fundamental Physics Lost Its Way” — tells you what to expect: a polemical argument from a writer who won’t be pulling his punches. I was keen to discover whether Lindley, an astrophysicist and the author of several well-regarded books, including “Uncertainty” and “The Science of Jurassic Park,” follows a line of reasoning that we’re beginning to see more frequently in popular science writing today: another full-throated critique of the more exotic speculations in theoretical physics like superstring theory, parallel universes, the properties of black hole event horizons and the hidden dimensions of space and time. Progress in our understanding of these phenomena seems lately to have stalled. Maybe Lindley, I thought, would offer some guidance as to how “fundamental physics” could find its way back to the right path.

Wider discussions about the nature of science and how it works are vitally important in our world of shouty social media, conspiracy theories, fake news, confirmation bias and cognitive dissonance. We need to trust the scientific method when it comes to issues like climate change or vaccines. But the multiverse theory? Is that even proper science?

Lindley begins with the Greek philosophers, notably Plato, who he says was not interested in the physical world, only in theorizing about it from on high, contemplating its mathematical (geometrical) beauty. Even worse, he looked with disdain at observational science. By contrast, his student Aristotle, interested in examining the world around him and trying to explain it, is a better fit as a precursor to the modern-day scientist. But Aristotle too came unstuck, for, as Lindley explains, he would come up with a hypothesis about some aspect of nature, then sift through his data to cherry-pick those that agreed with it — committing what we would now call confirmation bias, which, by the way, is how a lot of pseudoscience and conspiracy theories on the internet work.

Of course, Lindley reminds us, what constitutes a good scientific theory depends on the scientific context of its time. Surely not, you might think; don’t proper scientific theories have to satisfy timeless criteria such as explaining all the phenomena the theories they displace are able to, being able to make testable predictions, being repeatable, and so on? Well, yes, but here is where we get to Lindley’s central thesis: Contemporary theoretical physicists seem to have reverted to the idealized philosophy of Platonism. As he puts it, “The spirit of Plato is abroad in the world again.