\subj{Ockham's razor (Occam's razor) } A rule in science and philosophy stating that entities should not be multiplied needlessly, which is interpreted to mean that (1)~the simplest of two or more competing theories is preferable, and that (2)~an explanation for unknown phonomena should first be attempted in terms of what is already known. 如果有數個理論都可以接受，採用最簡單的那個 面對一個未知的現象，盡可能用已知的理論解釋