Consciousness is thought by many to define what it is to be human. We know that animals are conscious to some extent, but they don’t have what we have in that department. So if we can explain how human self-awareness works it will be a Rosetta Stone to understanding what makes our species so odd, or, depending on your view, so special.

Also: big brains love exercise. And the great thing about this topic is that it can be tackled by biologists, neurologists, philosophers, physicists and even novelists. It’s an interdisciplinary, no-holds-barred intellectual wrestling match.

Emily Thornberry said the quiet part out loud on immigration

Harry Potter is for infantilised millennials

The absurdity at the heart of the junior doctors’ strikes

Michael Pollan, an American journalist and academic who works at both Harvard and Berkeley, comes from a literature background but is fluent in the relevant science. His book gives a lucid survey of the numerous hypotheses about how consciousness works and what it really ‘is’. But it’s more than a tour d’horizon. Pollan sits down over pots of tea with many experts in the field to interview them; he tests and enlarges competing ideas. He is no credulous scribe, either, but a critical listener. ‘I found this very hard to believe,’ he will often comment over the Lapsang.

It starts with a psychedelic trip and a suggestion that plants may be conscious. The roots of plants do direct as well as nourish the leaves; time-lapse cameras show climbers putting out precarious tendrils in the ‘hope’ of finding a vertical. So plants have at least a sense of purpose. They also die. And what is death but an absence of consciousness? But they are not conscious as we are. So before we start considering our moral obligations towards wisteria, it seems clear that the problem here is not a biological but a semantic one. You can be sentient and purposeful without being ‘conscious’. We probably therefore need new words for different degrees of the faculty under discussion – from that possessed by the daisy via that of the crow or bonobo and onwards to........

© The Spectator