The dominant interpretation of the quantum wave function sees it as real – as part of the physical furniture of the universe. Some even go as far as to argue that the entire universe is a quantum wave function. But this interpretation runs into a number of problems, including a clash with Einstein’s theory of relativity. Karl Popper prize-winner, Eddy Keming Chen, suggests that we instead interpret the wave function as the basis for a law of nature that describes how particles, fields and ordinary objects move through space and time. That way, a number of puzzles around quantum mechanics are resolved.

Believe me when I say it's easy to love quantum mechanics—the fundamental rules that describe our physical world, starting at the microscopic level —but hard to interpret what it’s really about. Quantum mechanics is unquestionably useful as an algorithm for predicting the outcomes of experiments and has given birth to many technological innovations — from MRIs to semiconductors. But when it comes to the question of what quantum mechanics tells us about the nature of physical reality, things get very complicated, very quickly. Does quantum mechanics really reveal what exists at the fundamental level of the universe?