The sequel to Iain McGilchrist’s much-lauded The Master and His Emissary (2009) occupies two mighty volumes. Nearly 1,600 pages of text are supported by 2,500 references and thousands of footnotes soliciting the reader’s attention from the margins of the pages. The purpose of this magnum opus is to ‘convey a way of looking at the world quite different from the one that has largely dominated the West for at least three hundred and fifty years – some would say as long as two thousand years’. In pursuit of this aim, McGilchrist offers wide-ranging, indeed world-ranging, investigations ultimately anchored to the arguments he advanced in his earlier book.

That book was built around the claim that the two hemispheres of the brain attend differently to what is around us. As McGilchrist sees it, the attention of the left hemisphere is largely narrow beam and sharply focused, while that of the right hemisphere is wide, sustained and vigilant, connecting with the bigger picture and underpinning emotional and social intelligence. Because it constructs devitalised, simplified, thin representations of the world, based on parts rather than wholes, the left hemisphere gets us into all sorts of cognitive and emotional trouble and makes us more likely to be taken in by illusions. Worse still, it is ignorant of its own ignorance and is less self-critical than the circumspect right hemisphere. The left hemisphere sees truth as a thing while the right hemisphere sees it as a process. The left hemisphere prefers consistency over truth, adopting ‘a reductionist strategy’ to offer us a perspective on the cosmos as ‘meaningless, purely material’. All this matters because, McGilchrist believes, the left hemisphere has assumed mastery over the right hemisphere when it should be its obedient servant.

There are many problems with this story. One will be obvious from the previous paragraph: McGilchrist’s relentless personification of the hemispheres. Halves of brains are treated as if they were people. Then there is the puzzle of explaining how McGilchrist escaped the tyranny of his own left hemisphere when we are all apparently in thrall to this inner Toad of Toad Hall. Does he have a third hemisphere from which he can view, and pass judgement on, the other two?

He mentions this challenge but dismisses it in a manner that seems to mirror the behaviour he ascribes to the left hemisphere. But it cannot be ignored, because the idea of a viewpoint from which the hemispheres can be judged cannot be accommodated in his hemisphere-centric interpretation of our nature. The very existence of his thesis demonstrates that we are not confined to a McGilchristian cerebral prison; indeed, we inhabit a realm woven out of trillions of cognitive, emotional and social hook-ups, as part of a vast community of minds. We draw on the knowledge, expertise, history and wider culture of our fellow creatures. None of this is to be found inside the stand-alone brain, though we need brains to access the world and to sustain the science, philosophy and art McGilchrist uses to make and develop his arguments.

Given that McGilchrist’s story depends on a vast body of detailed neuroscientific research, his 140-page critique of empirical science – its methods, its institutions, the peer review process, publication bias and so on – sounds like the intense and sustained application of a saw to the branch on which he is sitting. At the very least, his condemnation of much of bioscience as an example of ‘left hemisphere capture’ is an attack on the sources upon which he depends to arrive at his conclusions. He acknowledges that what he is engaged in is ‘paradoxical’. But he is ‘not as troubled by that as others may be: it may be a sign that I am on the right path’. Equally, it might be a sign that he is on the wrong path.

McGilchrist uses the hemisphere hypothesis as a runway from which to take off on an intercontinental flight of ideas encompassing attention, perception, judgement, apprehension, intelligence (cognitive, emotional and social), creativity, schizophrenia and autism, truth (general and scientific), reason, logic, intuition, imagination, the one and the many, time, flow, space, matter, consciousness, value, purpose, the nature of the cosmos and the sense of the sacred. In short, Life, the Universe and Everything.

Some of his digression-rich explorations are welcome oases after the densely referenced neuroscience. They would be more refreshing if they did not always lead back to his twin obsessions with the naughty left hemisphere – that arrogant know-nothing know-all – and the saintly right hemisphere. Admittedly, he does qualify this in places: for example, he denies that he wishes to reduce our mental capacities to patterns of brain activity. But the claim, for instance, that in creative minds the left hemisphere’s inclination to preserve existing models at all costs is corrected by the right hemisphere acting as ‘devil’s advocate’ sounds pretty reductive.

I am sympathetic to some of McGilchrist’s views. His assault on the spatialisation of time, his case for putting the perceiver back into physics, his opposition to the view that living organisms are machines and his critique of neuroscientific experiments that supposedly prove we have no free will are well supported, if not particularly original. The rich seasoning of quotations from scientists, philosophers, mystics, divines and poets makes for some enjoyable reading and the writing is for the most part admirably clear. Ultimately, however, this endless book’s crushing burden of erudition – and McGilchrist’s tendency in places to cite a stream of authorities (with impressive academic titles or Nobel Prizes) as a substitute for a clearly laid out argument – wearied me. Perhaps I am too left-hemisphere.

These massive volumes, which incidentally are beautifully produced and illustrated, will be treasured by true believers in the Gospel of the Two Hemispheres and the doctrine that the left hemisphere leaves us ‘divorced from Nature, alienated from the structures and traditions of a stable society, and indifferent to the divine’. I am not persuaded that, if the hegemony of the left hemisphere remains unchallenged, Western civilisation will collapse. While The Matter with Things offers some interesting insights into our nature and the world in which we find ourselves, they are devalued by being subordinated to what ironically seems a rather reductionist critique of reductionism.