 Man is the only animal that laughs and weeps: for he is the only animal that is struck with the difference between what things are, and what they ought to be. We weep at what thwarts or exceeds our desires in serious matters; we laugh at what only disappoints our expectations in trifles… . To explain the nature of laughter and tears, is to account for the condition of human life; for it is in a manner compounded of the two! It is a tragedy or a comedy—sad or merry, as it happens… . Tears may be considered as the natural and involuntary resource of the mind overcome by some sudden and violent emotion, before it has had time to reconcile its feelings to the change of circumstances: while laughter may be defined to be the same sort of convulsive and involuntary movement, occasioned by mere surprise or contrast (in the absence of any more serious emotion), before it has time to reconcile its belief to contrary appearances (Hazlitt 1819 [1907], 1).