So far as we know, all the fundamental laws of physics, like Newton's equations, are reversible. - Richard Feynman

The uncertainty principle “protects” quantum mechanics. Heisenberg recognized that if it were possible to measure the momentum and the position simultaneously with a greater accuracy, the quantum mechanics would collapse. So he proposed that it must be impossible.

"A few years after I gave some lectures for the freshmen at Caltech (which were published as the Feynman Lectures on Physics), I received a long letter from a feminist group. I was accused of being anti-women because of two stories: the first was a discussion of the subtleties of velocity, and involved a woman driver being stopped by a cop. There's a discussion about how fast she was going, and I had her raise valid objections to the cop's definitions of velocity. The letter said I was making the women look stupid.

The other story they objected to was told by the great astronomer Arthur Eddington, who had just figured out that the stars get their power from burning hydrogen in a nuclear reaction producing helium. He recounted how, on the night after his discovery, he was sitting on a bench with his girlfriend. She said, "Look how pretty the stars shine!" To which he replied, "Yes, and right now, I'm the only man in the world who knows how they shine." He was describing a kind of wonderful loneliness you have when you make a discovery.

The letter claimed that I was saying a women is incapable of understanding nuclear reactions.

I figured there was no point in trying to answer their accusations in detail, so I wrote a short letter back to them: "Don't bug me, Man!

The first principle is that you must not fool yourself, and you are the easiest person to fool.