Named after the friar William of Ockham, Occam's Razor is a heuristic by which we select among competing explanations. Ockham stated that we should prefer the simplest explanation with the least moving parts: it is easier to falsify (see: Falsification), easier to understand, and more likely, on average, to be correct. This principle is not an iron law but a tendency and a mindset: If all else is equal, it's more likely that the simple solution suffices. Of course, we also keep in mind Einstein's famous idea (even if apocryphal) that 'an idea should be made as simple as possible, but no simpler.'