Antitheism (sometimes anti-theism) is the opposition to theism. The term has had a range of applications. In secular contexts, it typically refers to direct opposition to organized religion or to the belief in any deity.
The Oxford English Dictionary defines antitheist as "One opposed to belief in the existence of a god". The earliest citation given for this meaning dates from 1833.Antitheism has been adopted as a label by those who regard theism as dangerous, destructive, or encouraging of harmful behavior. Christopher Hitchens offers an example of this approach in Letters to a Young Contrarian (2001), in which he writes: "I'm not even an atheist so much as I am an antitheist; I not only maintain that all religions are versions of the same untruth, but I hold that the influence of churches, and the effect of religious belief, is positively harmful."
Other definitions of antitheism include that of the French Catholic philosopher Jacques Maritain (1953) for whom it is "an active struggle against everything that reminds us of God" (p. 104), and that of Robert Flint (1877), Professor of Divinity at the University of Edinburgh. Flint's Baird Lecture for 1877 was entitled Anti-Theistic Theories. He used it as a very general umbrella term for all opposition to his own form of theism, which he defined as the "belief that the heavens and the earth and all that they contain owe their existence and continuance to the wisdom and will of a supreme, self-existent, omnipotent, omniscient, righteous, and benevolent Being, who is distinct from, and independent of, what He has created." He wrote:
In dealing with theories which have nothing in common except that they are antagonistic to theism, it is necessary to have a general term to designate them. Anti-theism appears to be the appropriate word. It is, of course, much more comprehensive in meaning than the term atheism. It applies to all systems which are opposed to theism. It includes, therefore, atheism, but short of atheism there are anti-theistic theories. Polytheism is not atheism, for it does not deny that there is a deity; but it is anti-theistic since it denies that there is only one. Pantheism is not atheism, for it asserts that there is a god; but it is anti-theism, for it denies that god is a being distinct from creation and possessed of such attributes as wisdom, and holiness, and love. Every theory which refuses to ascribe to a god an attribute which is essential to a worthy conception of its character is anti-theistic. Only those theories which refuse to acknowledge that there is evidence even for the existence of a god are atheistic.