Berkeley's Treatise Concerning the Principles of Human Knowledge was published in 1710, when he was only twenty-five. The public silence that greeted it stunned him. Even the ridicule that he had anticipated was initially confined to private circles. No doubt this mortifying experience reinforced his belief “that whatever doctrine contradicts vulgar and settled opinion” must “be introduced with great caution into the world”. It had, indeed, been for this reason that he had “omitted all mention of the non-existence of matter in the title-page, dedication, preface, and introduction to” his performance. In this way he hoped that “the notion of [immaterialism] might steal unawares on the reader, who possibly would never have meddled with a book that he had known contained such paradoxes”.