Eric Hoffer is the apotheosis of the self-made man's self-made philosopher. His nearest competitor is Harry Golden, but then has Harry Golden read Montaigne? ""I went up into the mountains near Lake Tahoe,"" says Hoffer in Calvin Tomkins' expanded New Yorker profile, ""looking for gold and discovered Montaigne, and then down to the San Joaquin and cottonpicking and the workmen's barracks outside Stockton. . . ."" Hoffer's ""years on the bum"" as a migrant worker and then as a longshoreman date from the Twenties and continue into the Sixties. Probably the last authentic rugged individualist, Hoffer triumphed over adversity (he lost his eyesight at seven and miraculously regained it at seventeen), poverty and its ideological perils; (""On the waterfront,"" he notes wryly, ""the Communists all end up as successful real-estate dealers""), and the folly of materialism: (""I believe that God and the devil are fighting their battle, not in heaven but in man's soul""). As a self-educated savant with curious gaps: (""What the hell could Freud teach me?""), Hoffer wrote that popular ""classic"" on mass psychology and humanistic uplift. The True Believer, praised by Eisenhower, Johnson, academicians, businessmen, and Eric Sevareid, who arranged the TV interview last year which made Hoffer a famous man when he awoke the next day. Since Tomkins wisely lets Hoffer do most of the talking, there's a fetching lot of knockabout charm and that sort of shrewdness only genuine experience can bring. There's also, alas, hot air galore.