He holds that scientific practice is characterized by its continual effort to test theories against experience and make revisions based on the outcomes of these tests.
While Popper recognizes that scientists can and do hold onto theories in the face of failed predictions when there are no predictively superior rivals to turn to. In either case, however, this process must aim at the production of new, falsifiable predictions. When theories are falsified by such observations, scientists can respond by revising the theory, or by rejecting the theory in favor of a rival or by maintaining the theory as is and changing an auxiliary hypothesis. Popper’s falsificationist methodology holds that scientific theories are characterized by entailing predictions that future observations might reveal to be false. Popper’s early work attempts to solve the problem of demarcation and offer a clear criterion that distinguishes scientific theories from metaphysical or mythological claims.
His work is notable for its wide influence both within the philosophy of science, within science itself, and within a broader social context. He made significant contributions to debates concerning general scientific methodology and theory choice, the demarcation of science from non-science, the nature of probability and quantum mechanics, and the methodology of the social sciences. Karl Popper (1902-1994) was one of the most influential philosophers of science of the 20th century.