The wisdom of not knowing

On the Equality of All Things: Physics and Philosophy, Carlo Rovelli, Allen Lane, £20

85 Seconds to Midnight: A Physicist’s Argument Against Rearmament, Carlo Rovelli, Allen Lane, £9.99

Carlo Rovelli is now 70 and these two books have the air of closing arguments. Then again, all his books sound like closing arguments and he doesn’t really pay attention to his own death. I met him some years ago in Marseille and we sailed around on his pointu, a wooden boat with two pointed ends. It was, in the highest possible meaning of the word, fun.

The second book is really a pamphlet which demonstrates that billions of deaths from nuclear weapons are now very likely, bordering on the inevitable. The first, however, is much longer and denser and it strays far beyond his own discipline of physics. The title derives from the Chinese philosophy that Rovelli calls ‘anti-foundationalism’ and which should, he argues, take us beyond the usual categories of science.

‘There is no single theory of everything’, he writes: ‘modern science leads to the reality that electrons and minds, stones and laws, judgements and galaxies do not essentially differ in nature from one another. They are notions that illuminate each other.’

What follows is a series of six ‘lessons’, each of which requires careful reading. Philosophy and physics are very closely entwined and to be certain about anything is a mistake. ‘I find it wiser to abandon the goal of certainty altogether’, he writes.

So, for example, if he observes an atom, that provides no certainty because it is only seen by him; it will not appear in the same position to any other viewer. Both philosophers and physicists will be clutching their heads at this point. The motto of philosophers used to be sapere aude – dare to know. In the Rovellian view the motto should now be nescire aude – dare not to know. ‘Physics’, Rovelli drily observes, ‘is less useful than it is sometimes said to be.’

Quantum theory and the uncertainty principle subverted all conventional thinking and plunged us into a world that does not make (common) sense. But human minds are necessarily part of that world – it is mere superstition to believe that we are outside nature. Four centuries of modern science were, for Rovelli, all mistakes. At this point the philosophers appear – notably Kierkegaard. The truly real is not some objective finality; it is subjective: ‘any account whatsoever is perspectival, because there is no knowledge that is not embodied in nature.’

He continues: ‘This leaves the modern mind in a condition of radical but not unpleasant uncertainty. Our brains are in the world and the world is our home. Our reality does not exist in space, and it does not unfold in time. It is a fine, intricate and fragile fabric, like Venetian lace.’

I cannot help finding this inspiring. Conversations I have had with physicists over the years have failed to convince me. Their minds seemed to be stuck in a world that could be made to fall into place by their arcane language of equations. Fine, if that’s all you want, but it is not enough.

In a final flash of genius, Rovelli ends his book in the landscape of Milton’s Paradise Lost. Adam and Eve have been expelled from paradise by an angel with a flaming sword. Then:

The world was all before them, where to choose

Their place of rest, and Providence their guide:

They hand in hand, with wand’ring steps and slow,

Through Eden took their solitary way.

We are fallen but the world is there for us. We, finally, know exactly what we are – we are free.

Unfortunately, Rovelli’s second book sucks some of the fun out of this. 85 Seconds to Midnight is a dire warning that the world is close to a nuclear holocaust and the physicists have failed. ‘What animates these pages’, he writes, ‘is the collective bad conscience of my profession, theoretical physics.’Those scientists created weapons that could kill billions, possibly even remove all life from earth, and most of those weapons are in the hands of two of the most grossly irresponsible political leaders – Putin and Trump. ‘We have an exaggerated fear of each other’, writes Rovelli. ‘It is fear, unmotivated and irrational fear, that (then as now) makes us aggressive.’

The Germans did try to construct nuclear weapons, but came nowhere near succeeding. The Americans did. The Manhattan Project was launched in 1942 and its success was demonstrated to the world by the nuclear destruction of Hiroshima and Nagasaki in 1945. This was not done as part of the war effort – Japan was more or less defeated at that point – it was done because President Truman was aiming to make the US ‘the world’s only superpower’. This, as we now know, failed, and the world is littered with nukes.

Rovelli is very anti-American on this subject. He says that the US is a country ‘founded on genocides’. He puts nuclear weapons alongside the slave trade, the Civil War and the 30-odd post-war conflicts the US has initiated.

In such a context, a nuclear war is more likely than not – Rovelli’s title suggests we are very close to this cataclysm. For him, this is because our species is quite absurdly stupid. ‘We are afraid of our own shadow. We frighten each other, and this triggers wars. Could we be any dumber?’ Evidently not.

These are two very different books, but they are equally suffused with genius. Rovelli is a formidable thinker and a ferocious researcher. Read them both and you feel, first, much better and then much worse.