Karl Popper (1902–94) was an Austrian-born British philosopher who argued that scientific theories should continually be subject to “falsification.”
In his, The Logic of Scientific Discovery, Popper challenged the view that induction, as applied to the scientific realm, could lead to certain conclusions. Instead, Popper held that scientific observations and theories should always be subject to falsification. This means that when establishing a theory, the scientist should always be on the lookout for any data that would falsify his or her theory. If falsifying data is found, then the theory must be rejected or modified to fit the new data. If falsifying data is not found, the theory should be accepted, at least for a time, knowing that data in the future may falsify the theory. Popper’s approach makes the theories of science less certain and open to potential falsification in the future. For instance, an inductive study may lead us to conclude that all swans are white because that is what our observations have indicated. However, we should be open to the possibility that someday we may discover a swan that is not white. If this occurs, then we must jettison or modify the theory that “all swans are white.” But for now we can act upon the assumption that all swans are white.
Some have claimed that Popper’s theory is similar to that of David Hume who challenged traditional views of cause and effect. Others have complained that Popper’s view leads to an approach in which the main goal of science is simply to disprove established theories. And, if this is the case, does this mean there are no theories we can act upon? Popper, though, did believe that some theories have survived critical testing and, thus, are worthy to be acted upon.
In his early career, Popper was associated with the Logical Positivists who were very negative toward metaphysical knowledge. Popper, however, never held that metaphysical and non-scientific matters were meaningless. In The Open Society and Its Enemies, Popper addressed political philosophy. He advocated open societies and defended democracy. He also offered objections to the totalitarian views of Plato and Karl Marx.
Popper taught at Canterbury University, New Zealand from 1937 to 1945. Later, he was a professor at the University of London.