Karl Popper (1902–1994) is best known as one of the most prominent philosophers of science.

Popper says that in order for a theory to be scientific in nature, it must be potentially falsifiable — that is, any hypothesis is only scientific in nature if it there is some logical possibility that would falsify that hypothesis. On the other hand, unfalsifiable things, such as logical truths or religious claims, are not scientific in nature — there is no way to prove them to be false.

According to Popper, scientific claims are never fully verified, they are only corroborated very consistently by experience. As long as there remains a logical possibility that any claim is false, it cannot be claimed to be true with perfect confidence. Hence, science must admit, and always be aware of, the problem of induction. Rather than making claims which may turn out to be false, it is the duty of science to propose falsifiable hypothesis and then, over the course of time, test them and adjust theories accordingly.

Selected Works

• The Logic of Scientific Discovery (1934)
• The Open Society and Its Enemies (1945)
• Conjectures and Refutations (1963)
• Objective Knowledge: An Evolutionary Approach (1972)
• Knowledge and the Mind-Body Problem: In Defence of Interaction (1994)