The question of how the brain gives rise to subjective experience is the hardest of all. Mathematicians think they can help, but their first attempts have thrown up some eye-popping conclusions

Darren Hopes

THEY call it the “unreasonable effectiveness of mathematics”. Physicist Eugene Wigner coined the phrase in the 1960s to encapsulate the curious fact that merely by manipulating numbers we can describe and predict all manner of natural phenomena with astonishing clarity, from the movements of planets and the strange behaviour of fundamental particles to the consequences of a collision between two black holes billions of light years away. Now, some are wondering if maths can succeed where all else has failed, unravelling whatever it is that allows us to contemplate the laws of nature in the first place.

It is a big ask. The question of how matter gives rise to felt experience is one of the most vexing problems we know of. And sure enough, the first fleshed-out mathematical model of consciousness has generated huge debate about whether it can tell us anything sensible. But as mathematicians work to hone and extend their tools for peering deep inside ourselves, they are confronting some eye-popping conclusions.

Not least, what they are uncovering seems to suggest that if we are to achieve a precise description of consciousness, we may have to ditch our intuitions and accept that all kinds of inanimate matter could be conscious – maybe even the universe as a whole. “This could be the beginning of a scientific revolution,” says Johannes Kleiner, a mathematician at the Munich Centre for Mathematical Philosophy in Germany.

If so, it has been a long time coming. Philosophers have pondered the nature of consciousness for a couple of thousand years, largely to no avail. Then, half a century ago, biologists got involved. They …