You know that situation where you expect an important email from someone but you don’t get it? At first you think the other person is busy, but soon you find yourself making up conspiracy theories. That usually doesn’t help so the next time this happens, keep the following in mind. I found it on Wikipedia and it’s called: ‘Occam’s razor‘, a principle from philosophy and named after William of Ockham, a Franciscan friar who studied logic in the 14th century (yeah, quite a long time ago). The principle says that if the only difference between two explanations is how complex they are, choose the simpler one, for the one that involves the fewest guesses, is probably the right one. Another way of saying it: the more assumptions you have to make, the more unlikely an explanation is. Example: Two trees have fallen down during a windy night. Consider these two possible explanations: A) The wind has blown them down. B) Two meteorites have each taken one tree down, and after that collided and removed any trace of themselves. Even though both explanations are possible, the second explanation needs several assumptions to all be true and is probably the wrong answer. Occam’s razor also often comes up in medicine when there are many explanations for symptoms and the simplest diagnosis usually is the correct one. If a child has a runny nose, they probably have the common cold instead of a rare birth defect. Medical students are often told, “When you hear hoof beats, think horses, not zebras”. That’s if you don’t live in Africa of course.