Rousseau showed through life a singular proneness for being convinced by his own eloquence; he was always his own first convert; and this reconciles his power as a writer with his weakness as a man. He and all like him mistake emotion for conviction, velleity for resolve, the brief eddy of sentiment for the midcurrent of ever-gathering faith in duty that draws to itself all the affluents of conscience and will, and gives continuity and purpose to life.
Source: wiktionary