This is the quantum-mechanical counterpart of the action principle in classical mechanics. Something went wrong. If you move your piece into the same square as a different piece, you force the game to measure the state of that square. Another consequence of the canonical commutation relation is that the position and momentum operators are Fourier transforms of each other, so that a description of an object according to its momentum is the Fourier transform of its description according to its position. These quantum fluctuations in spacetime mean the fabric of the universe, like the ocean, will never be completely still.