Quentin Meillassoux (born 1967 in Paris, France) is a French philosopher. He teaches at the École Normale Supérieure, and is the son of the anthropologist Claude Meillassoux.
Meillassoux is a former student of the philosopher Alain Badiou, who has written that Meillassoux's first book Après la finitude (2006) introduces an entirely new option into modern philosophy, different from Kant's three alternatives of empiricism, scepticism, and dogmatism. The book was translated into English by philosopher Ray Brassier, Meillassoux's associate in the Speculative Realism movement.
In this book, Meillassoux argues that post-Kantian philosophy is dominated by what he calls "correlationism," the often unstated theory that humans cannot exist without the world nor the world without humans. In Meillassoux's view, this is a dishonest maneuver that allows philosophy to sidestep the problem of how to describe the world as it really is prior to all human access. He terms this pre-human reality the "ancestral" realm. In keeping with the mathematical interests of his mentor Alain Badiou, Meillassoux claims that mathematics is what reaches the primary qualities of things as opposed to their secondary qualities as manifested in perception.
Meillassoux tries to show that the agnostic scepticism of those who doubt the reality of cause and effect must be transformed into a radical certainty that there is no such thing as causal necessity at all. This leads Meillassoux to proclaim that it is absolutely necessary that the laws of nature be contingent. The world is a kind of hyper-chaos in which the principle of sufficient reason is abandoned even while the principle of non-contradiction must be retained.
For these reasons, Meillassoux rejects Kant's so-called Copernican Revolution in philosophy. Since Kant makes the world dependent on the conditions by which humans observe it, Meillassoux accuses Kant of a "Ptolemaic Counter-Revolution."
Several of Meillassoux's articles have also appeared in English in the British philosophical journal Collapse, and have helped to spark rapid growth of interest in his work in the Anglophone world. His still-unpublished dissertation L'inexistence divine (1997) is forthcoming in book form.