Should a traveller, returning from a far country, tell us, that he had seen a climate in the fiftieth degree of northern latitude, where all the fruits ripen and come to perfection in the winter, and decay in the summer, after the same manner as in England they are produced and decay in the contrary seasons, he would find few so credulous as to believe him. I am apt to think a traveller would meet with as little credit, who should inform us of people exactly of the same character with those in Plato's republic on the one hand, or those in Hobbes's _Leviathan_ on the other. There is a general course of nature in human actions, as well as in the operations of the sun and the climate. There are also characters peculiar to different nations and particular persons, as well as common to mankind. The knowledge of these characters is founded on the observation of an uniformity in the actions that flow from them; and this uniformity forms the very essence of necessity. I can imagine only one way of eluding this argument, which is by denying that uniformity of human actions, on which it is founded. As long as actions have a constant union and connexion with the situation and temper of the agent, however we may in words refuse to acknowledge the necessity, we really allow the thing. Now, some may perhaps find a pretext to deny this regular union and connexion. For what is more capricious than human actions? What more inconstant than the desires of man? And what creature departs more widely, not only from right reason, but from his own character and disposition? An hour, a moment is sufficient to make him change from one extreme to another, and overturn what cost the greatest pain and labour to establish. Necessity is regular and certain. Human conduct is irregular and uncertain. The one therefore proceeds not from the other.