False premise

A false premise is an erroneous proposition on which a statement is made or conclusion is drawn. Since the premise (proposition, assumption, suggestion, or idea from which a conclusion is drawn)is not correct or not fully correct, the conclusion drawn may be in error. Since logical arguments always require a core assumption, that specific core assumption (or set of assumptions) must be valid in order to draw a valid conclusion, or to correctly link a cause and its effect. The general issue is causal relationships.

For instance, the statement, "Anyone who kills another person must be insane," presumes there is no valid reason to kill, and that all killing is linked with insanity.

• Killing exists as a component of human behavior. (premise)
• Killing is insane. (false premise)
• Therefore insanity is established in people who kill. (conclusion)

Given this premise, all armies at war would be insane (as would their generals and leaders), the death penalty would be insane, mercy killings would be insane, discontinuation of heart-lung function support on a 'brain-dead' person could be insane, defending one's own life or the lives of family or others would be insane, and so on. By extension, then, anyone killing another would naturally be subject only to an insanity plea in court, and never to regular prison for a murder they committed.

In reality, however, many of these points are debatable and might fall into the realm of a false premise.