Five men made up the Barbizon school of painting, which has influenced the entire art education of the world. And that those who have been influenced and helped most, deny their redeemer with an oath, is a natural phenomenon psychologists look for and fully understand. Greece had a group of seven thinkers, in the time of Pericles, who made the name and fame of the city deathless. Rome had a similar group in the time of Augustus; then the world went to sleep, and although there were individuals, now and then, of great talent, their lights went out in darkness, for it takes bulk to make a conflagration. Florence had her group of thinkers and doers when Michelangelo and Leonardo lived only a few miles apart, but never met. Yet each man spurred the other on to do and dare, until an impetus was reached that sent the names of both down the centuries. Boswell gives us a group of a dozen men who made each other possible--often helped by hate and strengthened by scorn. The Mutual Admiration Society does not live in piping times of peace, where glowing good-will strews violets; often the sessions of this interesting aggregation are stormy and acrimonious, but one thing holds--the man who arises at this board must have something to say. Strong men, matched by destiny, set each other a pace. Criticism is full and free. The most interesting and the most successful social experiment in America owed its lease of life largely to its scheme of Public Criticism, a plan society at large will adopt when it puts off swaddling-clothes. Public Criticism is a diversion of gossip into a scientific channel. It is a plan of healthful, hygienic, social plumbing. England produced one group of thinkers that changed the complexion of the theological belief of Christendom--Darwin, Spencer, Wallace, Huxley and Mill. But this group built on the French philosophers, who were taught antithetically by the decaying and crumbling aristocracy of France. Rousseau and Voltaire loved each other and helped each other, as the proud Leonardo helped the humble and no less proud peasant, Michelangelo--by absent treatment. Victor Hugo says that when the skulls of Voltaire and Rousseau were taken in a sack from the Pantheon and tumbled into a common grave, a spark of recognition was emitted that the gravedigger did not see. Voltaire was patronized by Frederick the Great, who, though a married man, lived a bachelor life and forbade women his court, and protected Kant with the bulging forehead and independent ways. Kant lived among a group of thinkers he never saw, but reached out and touched finger-tips with them over the miles that his feet never traversed.