Consensus facit legem - Stipulates that when two or more persons arrive at a good faith agreement, the law will insist on that agreement being carried out.⏎
Consuetudo pro lege servatur - "Custom is held as law". Where no laws apply to a given situation, the customs of the place and time will have the force of law.⏎
Dura lex, sed lex - "The law [is] harsh, but [it is] the law". It follows from the principle of the rule of law that even draconian laws must be followed and enforced; if one disagrees with the result, one must seek to change the law.⏎
Audi alteram partem or audiatur et altera pars - Refers to the idea that one cannot be fairly judged unless the cases for and against them have been heard.⏎