What would make you change your mind about a theory? For Karl Popper (1902–1994), the question belongs at the center of scientific inquiry. Researchers learn by proposing explanations and giving others a chance to find where they fail. That same willingness to revise a judgment connects his philosophy of science to his wider account of rational criticism.
Falsifiability and the growth of knowledge
A scientific theory makes claims that could conflict with experience. In Popper’s account of falsifiability, what matters is whether a theory rules out a conceivable result. Surviving a demanding test can count in its favor, while leaving it open to further tests. For the argument in context, start with Conjectures and Refutations: Summary and Key Ideas.
The problem of induction
David Hume asks how experience can justify expectations about cases we have yet to observe. Popper argues that a universal theory cannot be deduced from a collection of particular observations. Scientists can still use experience to test explanations. Alan Chalmers on deriving theories from facts sets out the logical problem behind this proposal.
Criticism, institutions and the open society
Popper’s critical rationalism starts from the possibility that any of us may be mistaken. Its practical question is how to arrange inquiry so that errors can be found and corrected. In politics, his idea of the open society emphasizes institutions that allow policies to be criticized and governments to be changed without violence. This connects the possibility of reform with the possibility of learning from mistakes.
Where to go next
Thomas Kuhn on scientific revolutions asks how research communities respond to anomalies. Chalmers on Lakatos’s research programmes considers how researchers revise a family of theories over time, and Chalmers on realism introduces Popper’s view that scientific theories can aim at truth while remaining conjectural.
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