So that if man pretends to see clear in darkness, if he goes in contradiction to the course of the seasons, or the action of the elements; if he pretends to remain under water without being drowned, to touch fire without burning himself, to deprive himself of air without being suffocated, to swallow poison without destroying himself, he receives from each of those infractions of the laws of nature a corporeal punishment proportionate to his fault; but if on the contrary, he observes and practises each of those laws according to the regular and exact relations they have to him he preserves his existence, and renders it as happy as it can be: and as the only and common end of all those laws, considered relatively to mankind, is to preserve, and render them happy, it has been agreed upon to reduce the idea to one simple expression, and to call them collectively the law of nature..