Jean Meslier

In his Testament, Meslier repudiated not only the God of conventional Christianity, but even the generic God of the natural religion of the deists. For Meslier, the existence of evil was incompatible with the idea of a good and wise God. He denied that any spiritual value could be gained from suffering, and he used the deist's argument from design against God, by showing the evils that he had permitted in this world. To him, religions were fabrications fostered by the ruling elite; while the earliest Christians had been exemplary in sharing their goods, Christianity had long since degenerated into encouraging the acceptance of suffering and submission to tyranny as practised by the kings of France: injustice was explained away as being the will of an all-wise Being. None of the arguments used by Meslier against the existence of God were original. In fact, he derived them from books written by orthodox theologians in the debate between the Jesuits, Cartesians, and Jansenists. Their inability to agree on a proof for God's existence was taken by Meslier as a good reason not to presume that there were compelling grounds for belief in God. Meslier's philosophy was that of an atheist. He also denied the existence of the soul and dismissed the notion of free will. In Chapter V, the priest writes, "If God is incomprehensible to man, it would seem rational never to think of Him at all". Meslier later describes God as "a chimera" and argues that the supposition of God is not prerequisite to morality. In fact, he concludes that "Whether there exists a God or not... men's moral duties will always be the same so long as they possess their own nature". In chapters XXXIII and XXXIV, Meslier challenged Jesus' mental health by implying that Jesus "was really a madman, a fanatic" (étoit véritablement un fou, un insensé, un fanatique). Meslier wrote that kings and religion were the root cause of the suffering of the common people. In his most famous quote, Meslier refers to a man who "wished that all the great men in the world and all the nobility could be hanged, and strangled with the guts of the priests." Meslier admits that the statement may seem crude and shocking, but comments that this is what the priests and nobility deserve, not for reasons of revenge or hatred, but for love of justice and truth. Equally well-known is the version by Diderot, in the poem Les Éleuthéromanes: "And [with] the guts of the last priest let's strangle the neck of the last king" ("Et des boyaux du dernier prêtre serrons le cou du dernier roi". During the political unrest of May 1968, the radical students of the Sorbonne Occupation Committee paraphrased Meslier's epigram, stating that "humanity won’t be happy till the last capitalist is hung with the guts of the last bureaucrat." Social Criticism Meslier also vehemently attacked social injustice and sketched out a kind of rural proto-communism. All the people in a region would belong to a commune in which wealth would be held in common, and everybody would work. Founded on love and brotherhood, the communes would ally to help each other and preserve peace. An opponent of cruelty to animals, Meslier wrote that "it is an act of cruelty, of barbarism, to kill, to strike unconscious, and to cut the throat of animals, who do no harm to anyone, the way we do." He considered the lack of compassion and concern by Christians for animal suffering at the hands of man to be, according to Matthieu Ricard, further proof of "the nonexistence, or the malice, of their God."

In his book In Defense of Atheism (2007), the atheist philosopher Michel Onfray describes Meslier as the first person to write an entire text in support of atheism. He writes: Prior to announcing Meslier as the first atheist philosopher, Onfray considers and dismisses Cristóvão Ferreira, a Portuguese and former Jesuit who renounced his faith under Japanese torture in 1633 and went on to write a book titled The Deception Revealed. Onfray decides that Ferreira was not such a good candidate as Meslier, since Ferreira converted to Zen Buddhism. The Situationist cultural theorist Raoul Vaneigem praised Meslier's resistance to hierarchical authority, claiming that "the last full-fledged exemplars of priests genuinely loyal to the revolutionary origins of their religion were Jean Meslier and Jacques Roux fomenting jacquerie and riot". According to Colin Brewer (2007), who co-produced a play about Meslier's life, Historians argue about who was the first overt, post-Classical atheist but Meslier was arguably the first to put his name to an incontrovertibly atheist document. That this important event is largely unrecognised (Meslier was absent from both Richard Dawkins' and Jonathan Miller's recent TV series on atheism) is due partly to Voltaire who published, in 1761, a grossly distorted "Extract" that portrayed Meslier as a fellow-deist and entirely suppressed Meslier's anti-monarchist, proto-communist opinions. This account, however, ignores the earlier publication of a philosophical treatise entitled De non existentia Dei (On the non-existence of God) by Kazimierz Łyszczyński, executed for atheism in the Polish-Lithuanian Commonwealth in 1689. The treatise, of which fragments survive, ended with the words Ergo non est Deus (Therefore there is no God.)