Antitheism (sometimes anti-theism) is a term used to describe an opposition to theism. The term has had a range of applications and definitions. In secular contexts, it typically refers to direct opposition to the validity of theism, but not necessarily to the existence of a deity.
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.
However, Flint also acknowledges that antitheism is typically understood differently from how he defines it. In particular, he notes that it has been used as a subdivision of atheism, descriptive of the view that theism has been disproven, rather than as the more general term that Flint prefers. He rejects non-theistic as an alternative, "not merely because of its hybrid origin and character, but also because it is far too comprehensive. Theories of physical and mental science are non-theistic, even when in no degree, directly or indirectly, antagonistic to theism."
Opposition to the existence of a god or gods is frequently referred to as dystheism (which means "belief in a deity that is not benevolent") or misotheism (strictly speaking, this means "hatred of God"). Examples of belief systems founded on the principle of opposition to the existence of a god or gods include some forms of Atheistic or Theistic Satanism, and maltheism.
Another use of the term antitheism was coined by Christopher New in a thought experiment published in 1993. In his article, he imagines what arguments for the existence of an evil god would look like: "Antitheists, like theists, would have believed in an omnipotent, omniscient, eternal creator; but whereas theists in fact believe that the supreme being is also perfectly good, antitheists would have believed that he was perfectly evil." New's usage has reappeared in the work of Wallace A. Murphree.