Context: An Essay on Man is a philosophical poem which Pope addressed to Henry St. John, Lord Bolingbroke. The subject of Epistle II of the poem is the nature of man and his place in the universe. Like many of his contemporaries in the eighteenth century, Pope saw man as one link in the great chain of being, holding a middle place in that chain. Since man cannot know or understand the states of being above himself, he should study himself; or, as Pope puts it, "The proper study of mankind is man." In this epistle Pope, following his own advice, examines man and his nature. He sees that man has greatness and power on the one hand, but weakness and ignorance upon the other. He is governed by two principles, self-love and reason, both necessary to his place in the scale of being. Self-love is the principle which motivates man; reason is the principle which restrains him. The first verse paragraph of this epistle celebrates the duality of mankind and shows Pope's reasons for his conclusion that man's proper study is himself, that man should not try to pry into the nature, the knowledge, or the actions of God:
Know then thyself, presume not God to scan:The proper study of mankind is man.Plac'd on this isthmus of a middle state,A being darkly wise, and rudely great:With too much knowledge for the sceptic side,With too much weakness for the Stoic's pride,He hangs between; in doubt to act, or rest;In doubt to deem himself a god or beast;In doubt his mind or body to prefer;Born but to die, and reas'ning but to err;Alike in ignorance, his reason such,Whether he thinks too little, or too much:Chaos of thought and passion, all confus'd;Still by himself abus'd, or disabus'd;Created half to rise, and half to fall;Great lord of all things, yet a prey to all;Sole judge of truth, in endless error hurl'd:The glory, jest, and riddle of the world!