Reality is not What it Seems by Carlo Rovelli begins with a brief history of man’s ideas about how the physical world works. It then introduces modern theories about the quantum world, and about the loop theory of gravity.
Rovelli begins in classical Greece with Democritus, who first conceived of the idea of atoms. Rovelli claims that Democritus’ reasoning still holds good today – the world cannot be infinitely divided, but is made up, finally, of small indivisible parts. Rovelli compares Democritus favourably with other Greek philosophers such as Plato, whose idea of reality is is quite absurd in comparison. He mourns the fact that we only know of Democritus through what was written about him by other ancients, as none of his work has survived.
Rovelli writes a history of physical science covering the major figures – Newton, Einstein, Rutherford, Heisenberg. This is brief and interesting. There are various anecdotes to keep the reader going, and the explanations of the science are clear and fairly easy.
He concludes each section with a simple diagram showing how these scientists and their peers conceived of the world at each stage of the process of discovery. Ideas such as space, time, particles and fields have all been used by physicists to describe reality, but the intention has always been to offer the most simplified interpretation. The introduction of quantum mechanics reduced the world to two key ideas – spacetime and quantum fields and Rovelli claims that these two have now been reduced to one. The world is made of covariant quantum fields!!
Reality is Not What it Seems is a convincing and inspiring book. Years ago I read Stephen Hawking’s A Brief History of Time, and found there were parts I could not understand. Since then I have read many books on this subject, and they have cast some light into the darkness, but this has perhaps been the best. Here are two others:
The issue of Schrödinger’s cat has always puzzled me. How can something exist and not exist at the same time? But Rovelli steers the reader round this issue quite simply. He then goes on to give an elegant explanation of how two particles can be linked whilst being far apart. This had been another stumbling block for me. But Rovelli makes it all very simple, and at the same time introduces the reader to some of the basics of information theory.
Rovelli goes on to explain why there is no such thing as infinity. At the smallest level, even when squashed in a black hole there is a limit to how small something can be. The size of the Planck constant, or some equation involving that, comes in there. At the other end of the scale, whilst vast numbers, beyond our comprehension may appear infinite, there is a finite number of particles.
The universe is an expanding bubble of quantum particles. Within that, like bubbles of soap, it consists of interlinked networks of matter. At the quantum level the world is a cloud of possibilities. Particles gather together in a cloud of uncertainty and become things or people. That’s all there is.
It is no surprise that as an Italian, Rovelli is quite critical of religion. I say that because the organised and politicised forms of religion must have been prominent in Italy, the land of the popes. The imposition of dogma is at the expense of true Christianity. Galileo is an example that would strike a scientist like Rovelli very hard.
For him religion is a myth, it’s just the tales the old men of the tribe tell. Only science can be true. Everything is a mystery. If science has not solved the mystery now, it will one day.
Rovelli seems very confident about this. But I’m not sure whether in the end science will replace religion. It does not look that way to me, in the USA or the Middle East! It seems there is a need for religion. Maybe that is just human weakness, or superstition.
But the environment, indeed the world, is in a parlous state,and science is just a tool. The so called myths of the Old Testament prophets, in the form of the three religions of the book, dominate the world. It is a truth that works. The clouds of particles that believe and have faith have prospered and grown, like the Bible said they would.
At times religion becomes corrupted, but we need it. It embodies the values of love, compassion and stewardship, which science can never have.