Although details should be consulted with articles on natural law and positive law, natural law is a legal concept which does not look for the origin of law (basis on which law can exist, namely source of law) in artificial provisions but considers that source of law is derived from generality (or what thought to be) and justice.
詳しくは自然法と実定法の記事に譲るが、自然法とは法の淵源（法律の拠って立つ根拠、すなわち法源）を人為的に定められたものに求めず、人の理性によって発見される、時代や地域を超越した普遍性（と思われるもの）と正義に由来すると考える法概念である。