He advanced falsification in lieu of the logical positivist idea of verificationism.[1] Falsificationism argues that it is impossible to verify that beliefs about universals or unobservables are true, though it is possible to reject false beliefs if they are phrased in a way amenable to falsification. Thomas Kuhn's idea of paradigm shifts offers a broader critique of logical positivism, arguing that it is not simply individual theories but whole worldviews that must occasionally shift in response to evidence.[3]