It was thus that Berkeley became known to “men of merit” in that brilliant society. He was also brought among persons on whom he would hardly have conferred this title. He tells Percival that he had attended several free-thinking clubs, in the pretended character of a learner, and that he there heard Anthony Collins, author of “the bold and pernicious book on free-thinking,” boast “that he was able to demonstrate that the existence of God is an impossible supposition.” The promised “demonstration” seems to have been Collins’ _Inquiry Concerning Human Liberty_, which appeared two years later, according to which all that happens in mind and matter is the issue of natural necessity. Steele invited Berkeley to contribute to the _Guardian_ during its short-lived existence between March and September, 1713. He took the _Discourse_ of Collins for the subject of his first essay. Three other essays are concerned with man’s hope of a future life, and are among the few passages in his writings in which his philosophy is a meditation upon Death. In May, Percival writes to him from Dublin that he hears the “new book of Dialogues is printed, though not yet published, and that your opinion has gained ground among the learned; that Mr. Addison has come over to your view; and that what at first seemed shocking is become so familiar that others envy you the discovery, and make it their own.” In his reply in June, Berkeley mentions that “a clergyman in Wiltshire has lately published a treatise wherein he advances something published three years ago in my _Principles of Human Knowledge_.” The clergyman was Arthur Collier, author of the _Clavis Universalis_, or demonstration of the impossibility of an external world(6).