Russell's teapot

Russell's teapot is an analogy by the philosopher Bertrand Russell (1872–1970), to show that the philosophic burden of proof has on a person making a claim that cannot be proven false. 
Russell used his analogy in for religion. He wrote that if he were to say without proof, that a teapot, too small to be seen by telescopes, orbits the Sun somewhere in space between the Earth and Mars, he could not expect anyone to believe him because his claim could not be proven wrong.
Russell's teapot is still used to talk about the existence of God.