" Rule 1, by dictating how a quantum system changes in time, plays the same essential role in the theory that Newton’s laws of motion played in pre-quantum physics. Like Newton’s laws, Rule 1 is deterministic. It takes an input state and evolves it to a definite output state at a later time. This means it takes input states which are constructed as superpositions to output states which are similarly constructed from superpositions. Probability plays no role. But measurements, as described by Rule 2, do not evolve superpositions to other superpositions. When you measure some quantity, like pet "

― Lee Smolin , Einstein's Unfinished Revolution: The Search for What Lies Beyond the Quantum