Was Keats right after all?

Mediterranean crockery has a lot to answer for. It famously spoke thus to John Keats: ‘Beauty is truth, truth beauty, — that is all/Ye know on earth, and all ye need to know.’ Well, even if true, it’s obviously not all one needs to know. But then Keats was never one for irritable reaching after fact and reason. Any attempt at ‘cold philosophy’ would, as he wrote in another poem, ‘unweave a rainbow’. It would also, the poet groaned, ‘empty the haunted air, and gnomed mine’. Gnomed mine? Really?

The Nobel-winning physicist Frank Wilczek, though, is determined to put the gnomes back into the mines. His eccentrically brilliant book is a ‘meditation’ on the possibility that beauty really is truth. From the Pythagorean mantra that ‘All things are number’, and Plato’s atomic theory (wrong in detail but surprisingly right in many principles), through to Newton’s work on light and gravity, and up to modern quantum theory, Wilczek offers a stirring defence of rationalism: the uncovering of truth through pure reason. These days, we tend to assume that empiricism is the only game in town. Yet time and time again, Wilczek shows, ideas in theoretical physics long precede the evidence that turns out to support them. To be sure, coming up with those ideas is hard work, as he puts it in a charmingly self-deprecating caption to a reproduction of Dürer’s engraving ‘Melancholia’, which he says ‘well depicts the frustrations I often encounter when using pure thought to comprehend reality’.

But which pure thoughts will be correct? In physics, the most beautiful set of equations is repeatedly the one that turns out to be true. ‘We propose equations with enormous symmetry and then check to see whether Nature uses them,’ Wilczek explains.