If you can’t explain it to a six-year-old, you don’t understand it yourself.

Albert Einstein

albert einstein 808x1024 - Albert Einstein - Explain it to a six-year-old - Quote
14 Mar 1951, Princeton, New Jersey, USA — Albert Einstein sticks out his tongue when asked by photographers to smile on the occasion of his 72nd birthday on March 14, 1951. — Image by © Bettmann/CORBIS

The above quote clearly illustrates what we know about quantum physics. In the sense that referring to another quote by the physicist Richard Feynman…

If you think you understand quantum mechanics, you don’t understand quantum mechanics.

Richard Feynman

No one can explain quantum physics to anyone, let alone a six-year-old, so by definition, we don’t understand quantum physics.