Falsificationism
Popper's criterion that scientific claims must be capable of being proven wrong.
Falsificationism was developed by Karl Popper, presented in The Logic of Scientific Discovery (originally Logik der Forschung, 1934; English translation 1959) and elaborated in subsequent works including Conjectures and Refutations (1963). Popper proposed falsifiability as the criterion of demarcation between scientific and non-scientific claims: a theory is scientific if and only if it is capable of being refuted by some possible observation, regardless of whether the refutation has actually occurred. The motivating insight was Popper's observation that Marxism and Freudian psychoanalysis seemed to explain everything that happened — there was no observation their adherents would accept as refuting the theory — while Einstein's general relativity made specific risky predictions that could have been refuted (and indeed could have been disconfirmed in the 1919 eclipse observations). For Popper, science proceeds not by induction from observations but through bold conjectures that survive attempts at refutation, with knowledge growing through elimination of false theories. Subsequent philosophy of science complicated this picture substantially: Quine-Duhem holism (we test webs of beliefs, not isolated propositions, so falsifications don't unambiguously target specific claims); Kuhn's paradigm shifts (science doesn't proceed through accumulated falsifications but through revolutionary changes); Lakatos's research programmes (theories have hard cores protected by auxiliary hypothesis adjustments); Feyerabend's anarchism. Falsificationism remains influential in scientific self-understanding (especially in physics and parts of biology) but is no longer the dominant philosophy-of-science position.
Core components
- Falsifiability as demarcation criterion (scientific vs non-scientific)
- Asymmetry of confirmation and falsification
- Bold conjectures as scientific virtue
- Risky predictions
- Critique of induction
- Science as conjecture-and-refutation
- Critical rationalism (broader Popperian methodology)
- Distinction between strict refutability and degrees of falsifiability
- Connection to open society and political philosophy
Primary use case
Philosophy of science and scientific methodology; demarcation between science and non-science (notably in critiques of pseudoscience); scientific self-understanding particularly in physics; influence on Imre Lakatos's research programmes; pedagogical framework in philosophy of science education; basis for arguments that some prominent scientific claims are insufficiently testable.
Common criticisms
- Quine-Duhem holism: we test theories together with auxiliary hypotheses, so any failed prediction can be saved by adjusting auxiliary assumptions rather than rejecting the target hypothesis
- Kuhn's argument that science doesn't actually proceed by falsification — paradigms persist despite anomalies until alternatives mature
- Lakatos's argument that even Einstein's GR was treated by physicists as 'protected' by auxiliary adjustments rather than refuted
- Bayesian critiques argue probabilistic confirmation, not deductive refutation, is the actual structure of scientific reasoning
- falsifiability is a graduated rather than binary property — many genuinely scientific claims are difficult to test
- Popper's account doesn't well capture historical sciences (cosmology, evolutionary biology, paleontology) where some claims are about unrepeatable past events
- falsificationism in popular use sometimes becomes 'pseudoscience accusation' deployed without engaging actual evidence.
Lineage
- Parent of
- Lakatosian Research Programmes
- Siblings
- Paradigm Shift, Lakatosian Research Programmes, Bayesian Epistemology