I haven't even started this post and my head hurts already! I blame that James Gleik who has written a review of a book entitled "The Unfinished Quest for the Meaning of Quantum Physics" by Adam Becker. Yeeeees, well, good luck with that one, Mr. Becker, although not to worry because I will probably buy it anyway, partly because I have been literally fascinated by the subject since I first stumbled upon it nearly 40 years ago but also because your reviewer, James Gleik, is one of those truly talented writers who can hold one's hand as he guides you through the lunatic asylum that is quantum physics and who has provided an excellent review.
I trust Baroness Emma Orczy will forgive me for paraphrasing her famous and excellent rhyme:
They seek it here, they seek it there
Those boffins seek it everywhere.
Is it in heaven or is it in hell?
That damned elusive particle.
I still remain somewhat uneasy in the realisation that above and below and all around my more-or-less known and measured world of causes and effects, actions and re-actions, there exists an entire universe-plus which might be summed up as operating on the 'make-it-up-as-you-go-along' principle! All of what I might call the 'solid state' of the universe is actually galvanised and energised by zillions, to the power of even more zillions, of 'particles' and 'waves' which defy inspection and which may only be judged by their effects. As Mr. Gleik puts it in his review:
Wave-particle duality. Everything there is — all matter and energy, all known forces — behaves sometimes like waves, smooth and continuous, and sometimes like particles, rat-a-tat-tat. Electricity flows through wires, like a fluid, or flies through a vacuum as a volley of individual electrons. Can it be both things at once?
The uncertainty principle. Werner Heisenberg famously discovered that when you measure the position (let’s say) of an electron as precisely as you can, you find yourself more and more in the dark about its momentum. And vice versa. You can pin down one or the other but not both.
The measurement problem. Most of quantum mechanics deals with probabilities rather than certainties. A particle has a probability of appearing in a certain place. An unstable atom has a probability of decaying at a certain instant. But when a physicist goes into the laboratory and performs an experiment, there is a definite outcome. The act of measurement — observation, by someone or something — becomes an inextricable part of the theory.
I simply do not understand it but at least I am in good company because the likes of Einstein, Bohr, Heisenberg and Schrödinger (including his famous cat!) didn't understand it either, although I must admit that their non-understanding was at a very much deeper level than my open-mouthed incomprehension.