This fallacy occurs when individuals take the lack of information about a certain subject as proof of either its existence or nonexistence. Essentially, it’s the belief that something is true because we don’t know it isn’t true, or, conversely, the disbelief in something because we don’t know that it is true. It is often used to justify a position that lacks a certain amount of evidence: proponents of extrasensory perception argue that because we don’t know everything there is to know about the brain that the brain can then send signals; UFO believers often use this argument when they argue that the lack of knowledge about lights or objects in the sky are proof of the existence of UFOs.
