An Austrian philosopher who settled in England, he changed the way we understand science. For him, a scientific theory cannot be proved true, but it can be tested and overturned by experience. He carried this critical attitude into politics, defending the open society against regimes that claim to own historical truth.
Core ideas
A theory is scientific only if it can, in principle, be refuted by tests
Knowledge advances by trial and error, eliminating false hypotheses
Open societies allow mistakes to be corrected and rulers replaced without violence
The tradition: Critical rationalism
Critical rationalism holds that no idea is above criticism and that we learn by submitting everything to tests. Popper created this approach and applied it to science and politics.
