Antony Flew

Antony Flew (1955) introduces the concept of theology and falsification by referring to John Wisdom's parable of the Believer and the Skeptic in reference to the existence of a beautiful garden in the jungle. The Believer asserts that there must be a gardener taking care of it regardless of whether he can be seen, heard or felt, while the Skeptic believes there is no gardener and the garden blooms independently of a caretaker. Even after setting a watch, patrolling with dogs and setting up an electrified fence, there is no physical evidence of a gardener, only the presence of a garden. However, the Believer in the parable does not waiver from his belief in the existence of the gardener despite the efforts of the Skeptic to question acceptance of this person based on the lack of physical evidence for his/her existence. The Skeptic questions the Believer's original assertion (Flew, 1955): "How is an invisible, intangible gardener any different from an imaginary gardener or no gardener at all?"

Thus, Flew (1955) uses the parable to show how those who believe in the presence of God accept their belief with no tangible supporting evidence as to God's existence. This argument emphasizes how for a concept or theory to be true, it must also be possible to prove that it is false. Believer's in God accept God's existence as a universal truth not subject to falsification, thus for Flew this premise alone disproves the possibility of God' existence. In purely logical terms related to the parable, if one proposes that if there is a garden, then there must be a gardener, then it must also be true that if there is no gardener, then there is no garden. This is referred to as the contrapositive; Flew (1955) regards this as being "equivalent to the denial of the negation of that assertion." Without being able to provide concrete physical evidence for the presence of a gardener, then one must logically conclude that there is no gardener and the original assertion (that there is a gardener because there is a garden) is false. Thus without a possibility of being proven false it is not open to falsification and this leads to Flew's argument that the existence of God is an invalid concept, as it cannot be disproved.

Flew's (1955) argument continues with the idea that those who are agnostics do not believe that there are sufficient conditions that would warrant "sophisticated religious people" to reject the existence of God, mainly because