If an event can be produced by a number n of different causes, the probabilities of the existence of these causes, given the event (prises de l'รฉvรฉnement), are to each other as the probabilities of the event, given the causes: and the probability of each cause is equal to the probability of the event, given that cause, divided by the sum of all the probabilities of the event, given each of the causes.
Pierre-Simon Laplace[Science] dissipates errors born of ignorance about our true relations with nature, errors the more damaging in that the social order should rest only on those relations. TRUTH! JUSTICE! Those are the immutable laws. Let us banish the dangerous maxim that it is sometimes useful to depart from them and to deceive or enslave mankind to assure its happiness.
Pierre-Simon LaplaceAll the effects of Nature are only the mathematical consequences of a small number of immutable laws.
Pierre-Simon LaplaceThe simplicity of nature is not to be measured by that of our conceptions. Infinitely varied in its effects, nature is simple only in its causes, and its economy consists in producing a great number of phenomena, often very complicated, by means of a small number of general laws.
Pierre-Simon Laplace