Lectures on The English Comic Writers by William Hazlett.
 
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. We shed tears from sympathy with real and necessary distress; as we burst into laughter from want of sympathy with that which is unreasonable and unnecessary, the absurdity of which provokes our spleen or mirth, rather than any serious reflections on it.
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 these two! It is a tragedy or a comedy—sad or merry, as it happens. The crimes and misfortunes that are inseparable from it, shock and wound the mind when they once seize upon it, and when the pressure can no longer be borne, seek relief in tears: the follies and absurdities that men commit, or the odd accidents that befal them, afford us amusement from the very rejection of these false claims upon our sympathy, and end in laughter......
 
With an introductionby R Brimley Johnson