Argument from ignorance, also known as appeal to ignorance, is a fallacy in informal logic. It asserts that a proposition is true because it has not yet been proven false or a proposition is false because it has not yet been proven true. If some proposition has not yet been proved true, we are not entitled on that ground alone to conclude that it is false and vice versa. In debates, appealing to ignorance is sometimes an attempt to shift the burden of proof. The term was likely coined by philosopher John Locke in the late 17th century.

The Demon-Haunted World: Science as a Candle in the Dark is a 1995 book by the astrophysicist Carl Sagan.. In it, Sagan aims to explain the scientific method to laypeople and to encourage people to learn critical and skeptical thinking. He explains methods to help distinguish between ideas that are considered valid science and those that can be considered pseudoscience. Sagan states that when new ideas are offered for consideration, they should be tested by means of skeptical thinking and should stand up to rigorous questioning.