Argument from Incredulity

Also called the argument from incredulity, the fallacy has roots in ancient theological debate. Anselm of Canterbury's ontological argument (c. 1078 CE) and related arguments contain elements of it — reasoning that what cannot be conceived as otherwise must be divinely ordained. The fallacy gained its modern scientific context in 20th-century debates between evolutionary biology and creationism, where Michael Behe's "irreducible complexity" argument was widely identified as an instance. Richard Dawkins labeled it explicitly in his 2004 book The Ancestor's Tale.