Percy Bysshe Shelley - The Necessity of Atheism, published 1811
This short pamphlet was published on 13 February 1811. It immediately caused a strongly hostile reaction which eventually led to all undistributed copies being burnt.
Shelley was punished with expulsion from Oxford University. The pamphlet proceeds rationally, boldly, in the cause of truth and reform, to present its rebel's dangerous argument. It identifies three sources of belief: the evidence of the senses (strongest); reason; and the testimony of others (weakest).
At the end, Shelley states his conclusion succinctly: "...it is evident that having no proofs from any of these sources...the mind cannot believe in the existence of a God".