The world divides between creeps and jerks. History can be seen as a long, unedifying creep, or what one of Alan Bennett’s characters called ‘one fucking thing after another’. Alternatively, it might be seen as consisting of jerks – that’s to say, big events that revolutionise the world (the invention of the printing press, the advent of steam, the French Revolution, Hiroshima, Tim Berners-Lee’s creation of the world wide web). The latter position is essentially that of the philosopher Alain Badiou. The French Maoist maintains that the significance of events that stand out from the usual blah of history can only be grasped retroactively – vindicating Zhou Enlai’s reply when asked in 1972 about the significance of the French Revolution: ‘Too early to say.’

A similar split occurs in evolutionary theory, where the zoologist Richard Dawkins (creep) and the paleontologist Stephen Jay Gould (jerk) disputed over the fundamental nature of life. The former, a good Darwinian, insisted on the slow nature of evolutionary change (phyletic gradualism), while Gould and his followers drew attention to the western Spotted Owl. Thanks to the relative geographical isolation of regions such as the California Cascades, three Spotted Owl species arose quickly where once there had been one – or what a researcher, quoted here, called ‘rapid evolutionary events punctuating a history of stasis’. By contrast, Graham Harman tells us, sharks seem not to evolve. Circulating freely through the oceans, they don’t become isolated enough to form new species and, like Habsburg emperors, have small gene pools.

These and other distinctions between the continuous and the discrete are the subjects of quite the most unexpectedly joyous philosophical romp I’ve read in ages, in which the Californian professor tries to settle a dispute that has bedevilled philosophers since Heraclitus first pulled on the proverbial toga. The pre-Socratic maintained that everything was in flux, which must have made it tricky to find his toga in the wardrobe – if indeed it makes sense to speak of toga or wardrobe, given the universally prevailing flux conditions. At the other extreme, the Enlightenment mathematician Gottfried Leibniz declared that ultimate reality consists of discrete, windowless monads that can only casually interact, thanks to God’s grace. This creates an immediate philosophical problem. Once God is dead, which is what Nietzsche in his whimsical way suggested, then all these windowless monads, like sulking couples in bitter divorces, won’t be on speaking or any other terms but be absolutely, eternally individual and alone. A chilling thought.

Harman develops his theme through diverting chapters on historiography (featuring an excursus on why Mongolian warlords gave up raping and pillaging mimsy city dwellers to become mimsy city dweller themselves); evolution; the philosophy of science (in which Thomas Kuhn’s jerky notion of paradigm shifts, naturally enough, gets an airing); and architecture (think the contrast between Le Corbusier’s discrete lump of modernism, the Unité d’Habitation in Marseille, and the continuous surfaces of Zaha Hadid’s east London aquatic centre). Engaging chapters cover many other fields of human endeavour, though I’d have liked Harman to have applied his continuous/discrete taxonomy to economics, where boom-bust policies, not to mention the ongoing feud between Trussian growth and Thunbergian degrowth philosophies, seem ripe for such analysis. This is a bravura work, written in pellucid, lively prose, from which I’ve learned more about trilobites, transfinite numbers, Aristotle’s account of substance and Henri Bergson’s theory of endosmosis than I can do justice to in a review.

Naturally enough, Harman spends much time in the thickets of 20th-century physics, where the dispute over whether ultimate reality is particle-like or wavelike has left many a brainiac sobbing into their particle accelerator. ‘It is very important to know,’ insisted the physicist Richard Feynman in his 1979 lectures on quantum electrodynamics, that ‘light behaves like particles, especially for those of you who have gone to school, where you were probably told something about light behaving like waves’.

Feynman’s idea was that all the saps who have been to school (most of those attending his lectures, you’d think) needed to be disabused of the thought, made popular by Thomas Young’s interference experiments in 1803 and James Clerk Maxwell’s work on electromagnetism in the 1860s, that light was fundamentally wavelike. Why was Feynman so sure he was right? ‘Every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering the same thing: light is made of particles.’

But it is only in detecting a particle that it will manifest as a particle. Or, as Harman puts it: ‘Until an interaction occurs, a particle is only a probability wave whose exact position is a matter of statistical possibility rather than certainty.’ We may not always know where a particle is, but we do know that whenever it is measured it will manifest as a particle.

Why does this matter? Because it challenges the view that everything works according to definite – one might say mechanical – laws: what’s called determinism. That mechanistic conception of reality for some extends even to human behaviour. If every human act is determined by heredity, then rapists and murderer cannot be held responsible for their actions. For others, there is something special about humans – their free will – which makes them different from the rest of the world they inhabit and justifies sending murders and rapists to jail.

What? Are we dealing in thinking bricks now?

You may have written essays – I know I have – defending compatibilism, the deeply strange yet appealing idea that both free will and determinism are true, with its corollary that the worst criminals should be jailed even if their heredity, environment and poor diet explain and even excuse why they have committed their crimes. In this book, Harman defends something like compatibilism by proposing the idea that ultimately reality is not wavelike nor particle-like but both. He shows how every individual, whether human, leonine or, as we will see, a brick, is half wave and half stone, both object and continuous whole. It’s an amazing idea, and will send Feynman spinning in his grave. It’s certainly a tricky position to hold. In the 20th century, physics, as Harman puts it, both ‘quantised reality’, conceiving it as tiny, discrete units (hence Planck’s theory of black body radiation) but also posited (thanks to Einstein’s general relativity) that entire regions of space-time are continuous waves (think of electromagnetic or gravitational fields).

Harman is behind a voguish movement in philosophy called object-oriented ontology, whose acronym OOO gives it a disarmingly camp Larry Grayson vibe. Its chief tenet is that anthropocentrism, which has governed most intellectual inquiry for two-and-a-half millennia, is a mistaken prejudice, typified by Descartes, who supposed that animals were essentially furry robots and that therefore kicking them was permissible. Near the end of the book, Harman writes: ‘We will no longer join with Descartes in supposing that animals, bricks, machines or nations have a cognitive life equal to zero.’ Wait, what? Bricks? Set aside for a moment Jeremy Bentham’s point about animal suffering (‘The question is not can they reason, nor can they talk, but can they suffer?’), we’re dealing in thinking bricks now? Is the phrase ‘thick as a brick’ offensive – to bricks? What can Harman mean?

A clue, perhaps, comes in extrapolating from Wittgenstein’s remark that ‘If a lion could talk we could not understand him’ – the implication being that a lion’s cognitive and sensory make-up is so different from ours that we, mere human mugs, can’t really grasp what’s going on in their collective bonces. The same, in principle – somehow – is true of bricks. In an age of wood wide webs where mushrooms talk to trees, perhaps this notion isn’t quite as outré as it might have seemed to our ancestors, but it’s still quite counterintuitive.

Harman’s philosophy is not the most batty on the block right now. The Karlsruhe-based Professor Peter Sloterdijk has maintained, in a vast trilogy seething with German compound nouns, that reality is best understood in terms of spheres, bubbles and ultimately a kind of global foam that extends beyond any human exceptionalism. Harman doesn’t quite pop Sloterdijk’s bubbles, but he does propose something equally opposed to the idea that humans are masters of their domains.

Like Sloterdijk, he’s keen to bust humans down to size by effecting an intellectual revolution that, if successful, amounts to the fourth great takedown of human hubris. First, Copernicus showed that we weren’t at the centre of the universe; next, Darwin demonstrated that we were products of evolutionary forces; then Freud showed us that we didn’t even know ourselves but were motivated by unconscious drives. Harman’s OOO suggests that the world is not understandable only by humans and that non-human entities have their thoughts. ‘To see a world in a grain of sand…’, wrote Blake. Well, yes; but to imagine that sand thinks, and just possibly feels pain when you build castles with it, is something else, beyond even the great poetic visionary’s mindset.

I don’t want to be sneery about OOO, but as an orthodox (Groucho) Marxist, I doubt whether the ultimate nature of reality is to be found on the inside of overwhelmingly non-human objects, which is the position Harman defends in pages 298-304. ‘Outside of a dog, a book is man’s best friend,’ said Groucho. ‘Inside of a dog, it’s too dark to read.’ But that’s a minor quibble with this heroically digressive, philosophically ardent and thoroughly enjoyable book.