If a tree falls in a forest and no one is there to hear it, does it make a sound? Perhaps not, some say.
And if someone is there to hear it? If you think that means it obviously did make a sound, you might need to revise that opinion.
We have found a new paradox in quantum mechanics — one of our two most fundamental scientific theories, together with Einstein’s theory of relativity — that throws doubt on some common-sense ideas about physical reality.
Quantum mechanics vs. common sense
Take a look at these three statements:
- When someone observes an event happening, it really happened.
- It is possible to make free choices, or at least, statistically random choices.
- A choice made in one place can’t instantly affect a distant event. (Physicists call this “locality”.)
These are all intuitive ideas, and widely believed even by physicists. But our research, published in Nature Physics, shows they cannot all be true — or quantum mechanics itself must break down at some level.