When two explanations both work, prefer the one with fewer assumptions

The medieval friar William of Ockham argued that entities should not be multiplied beyond necessity — don't invent extra causes or hidden variables if a simpler account explains the same facts. It isn't a guarantee of truth, just a tiebreaker: the simpler theory is easier to test, and easier to prove wrong if it isn't right.

— William of Ockham, Summa Logicae — c. 1323 — public domain