Can also be found in: synonyms financial encyclopedia. Natural lawn. An institution of moral and ethical principles considered inherent in nature or to be inferred separately from reason, usually in contrast to positive laws. Natural law 1. (Philosophy) an ethical belief or belief system considered inherent and discoverable in human nature by reason rather than revelation 2. (Philosophy) a non logically necessary truth; the laws of nature. See also logic 23 (Philosophy) that the authority of the legal system or some laws originates from the philosophical theory of rational legitimacy. In fact, the legal system that cannot be so legitimate has no authoritative natural law.
A principle or legal system believed to originate from nature, justification, or religion and to be ethically binding in human society.