1. Popper and the Poker Nick Aldridge

2. 45 minutes on... 1.The contestants 2.Popper: logic of science 3.Wittgenstein, meaning and metaphysics 4.Why Popper had it in for Wittgenstein 5.The “fight” 6.Towards a reconciliation?

3. Karl Raimund Popper CH FBA FRS Austrian-British philosopher and professor at the London School of Economics. Generally regarded as one of the greatest philosophers of science of the 20 th century Born: 1902, Vienna Died: 1994, London

4. Ludwig Wittgenstein Austrian-British philosopher and professor at Cambridge Widely regarded as one of the greatest philosophers of the 20 th century Born: 1889, Vienna Died: 1951, Cambridge

5. Popper on philosophy of science Why believe scientific theories? What makes science scientific? Popper’s answer: Account of the logic of scientific method and its advance

6. Early Wittgenstein & logical positivism “In order to determine the sense of a proposition, I should have to know a very specific procedure for when to count the proposition has been verified”. Wittgenstein and the Vienna Circle, p.47

7. Picture theory of meaning “A propositional sign is a fact...In a proposition a name is the representative of an object” (Tractatus 3.14; 3.22)

8. Tractatus and science Verifiability as: -Demarcation criterion -Meaning criterion Metaphysics becomes nonsense Science proceeds by induction

9. The problem of (with) induction The supposition that the future resembles the past, is not founded on arguments of any kind, but is derived entirely from habit. (David Hume, 1737)

10. How does Popper avoid induction? Theories are never verified: they remain conjectures They have the form of universal statements: “wherever A, then B” given right initial conditions No number of A & B can prove; one A & not-B can falsify: an asymmetry

11. Falsification and demarcation Gemini You may be feeling a bit reserved today… Promising new projects may present themselves.

12. Gravitational lensing: crucial experiment

13. Falsification isn’t simple/binary Ad hoc hypotheses Artificial theories & preference

14. Open Society and its Enemies (1945)

15. Popper’s Hegel-bashing “his philosophical arguments are not to be taken seriously... A major factor in bringing about the ‘age of intellectual dishonesty’...contributed to the rise of totalitarian philosophising”

16. Popper’s case against Wittgenstein

17. The scene is set

18. Popper’s story

19. The battle – did it happen? Wittgenstein’s disciples Popper’s modest tone

20. Anything in common? W: practice and “deflationism” Popper on inductive practices

21. Conclusions, reading Popper (1934, 1959) “Logic of Scientific Discovery”, (1946) “The Open Society and its Enemies” and (1976) “Unended Quest “ Wittgeinstein, (1922) “Tractatus Logico- Philosophicus” and (1953)“Philosophical Investigations” Child, “Wittgenstein” Edmonds & Eidinow (2001) “Wittgenstein’s Poker” Ladyman (2002) “Understanding Philosophy of Science”

22. Thank you!