Both in principle and in their private attitude toward mankind Johnson and Rousseau were irreconcilable opponents. Johnson had a voracious appetite for life, and was passionately concerned with the welfare of individual men and women; while Rousseau, although he was persuaded that he loved the human race, or would have loved it if he could, followed a solitary, self-centred course and, among a host of associates, protectors, disciples, made comparatively few friends whose opinions and support he valued. Here one remembers another literary dispute, held some hundred-and-fifty years later, when Henry James, writing to the youthful H.G. Wells, described their fundamental difference. "You," he explained, "don't care for humanity but think they are to be improved. I love humanity but know they are not!" Johnson, too, despite his capacity for deep affection, was a life-long pessimist; Rousseau, the suspicious and resentful exile, was an inveterate reformer, and launched the doctrine of "human perfectibility" that made so strong, and often so confusing, an appeal to English nineteenth-century Romantic poets. He was a teacher; but his chief aim was primarily to teach himself; if he desired to learn, he confessed, it was primarily in order to understand his own character.