There are, indeed, few pleasures or none, not even physical ones, which the company of others does not for the most part considerably increase, by some wonderful natural contagiousness. Every happy or joyful state of themind carries with it the urge for communication to others and sharing with them. Whatever is agreeable, pleasant, cheerful, witty, or humorous will hardly ever, indeed never, fail to spring up and burst forth from teh human heart, endeavouring to unfold itself amongst others. Nothing gives man greater joy than sharing his joy with others. For this reason, even if we were to suppose that everyone seeks his own pleasure or advantage, nevertheless, such is the nature of most pleasures and of the greatest ones, of such a kind are most of our desires, that they induce us to seek social life for its own sake almost without any reasoning, and make the offices of social life in themselves joyful and agreeable.
Francis Hutcheson, from the Inaugural lecture on the social nature of man.