1. A New Development Werner Heisenberg, 1901-1976 The fundamental laws of quantum physics are probabilistic Physics is not deterministic!

2. Arthur Eddington, 1882-1944 We’re composed of matter that obeys physical laws But the movement of fundamental particles is not deterministic So we can have free will after all!

3. So Epicurus Was Right! “If an atom were always carried along by natural necessary force, nothing would be up to us, since the mind would be moved in whichever way its atoms were.”

4. Determinist Objection Yes, quantum physics is indeterministic at the microscopic level Yes, quantum physics is indeterministic at the microscopic level But it’s fairly deterministic at the level of ordinary objects But it’s fairly deterministic at the level of ordinary objects Quantum effects mostly cancel each other out at that level Quantum effects mostly cancel each other out at that level The motion of each particular particle is uncertain, but not of an entire object The motion of each particular particle is uncertain, but not of an entire object

5. Indeterminist Response But some ordinary-size structures can amplify quantum indeterminism But some ordinary-size structures can amplify quantum indeterminism Example: a Geiger counter Example: a Geiger counter Another example: the human brain? Another example: the human brain?

6. Determinist Counter-Response But do quantum events cause our choices, or do our choices cause the quantum events? But do quantum events cause our choices, or do our choices cause the quantum events? If quantum events cause our choices, then we’re still being determined by something outside our control. If quantum events cause our choices, then we’re still being determined by something outside our control. If our choices cause quantum events, how? Aren’t we back to the spooky unmeasurable soul-force? If our choices cause quantum events, how? Aren’t we back to the spooky unmeasurable soul-force?

7. Are Reductive Materialism & Dualistic Spookiness Our Only Options? It’s often said that the tendency of scientific thought in the past 500 years is more and more to undermine the special status of human beings …

8. Copernicus and Galileo Help! Our planet isn’t at the center of the universe! Help! Our planet isn’t at the center of the universe!

9. Charles Darwin Help! We’re descended from apes! Help! We’re descended from apes!

10. Karl Marx Help! We’re controlled by economic forces! Help! We’re controlled by economic forces!

11. Sigmund Freud Help! We’re controlled by our subconscious! Help! We’re controlled by our subconscious!

12. But Parallel Philosophical Trends Have Been Reasserting Our Special Status Immanuel Kant, 1724-1804 Immanuel Kant, 1724-1804

13. But Parallel Philosophical Trends Have Been Reasserting Our Special Status G. W. F. Hegel, 1770-1831 G. W. F. Hegel, 1770-1831

14. But Parallel Philosophical Trends Have Been Reasserting Our Special Status Gottlob Frege, 1848-1925 Gottlob Frege, 1848-1925

15. But Parallel Philosophical Trends Have Been Reasserting Our Special Status Ludwig Wittgenstein, 1889-1951 Ludwig Wittgenstein, 1889-1951

16. But Parallel Philosophical Trends Have Been Reasserting Our Special Status John McDowell, b. 1942 John McDowell, b. 1942

17. According to Post-Kantian Philosophy: The truths of logic and mathematics do not depend on the nature of matter The truths of logic and mathematics do not depend on the nature of matter So logical relations cannot be explained in purely physical terms So logical relations cannot be explained in purely physical terms So nothing capable of grasping logical relations can be explained in purely physical terms either So nothing capable of grasping logical relations can be explained in purely physical terms either So human beings cannot be explained in purely physical terms So human beings cannot be explained in purely physical terms

18. A Crucial Distinction Enabling conditions: Enabling conditions: those that make something’s existence possible those that make something’s existence possible Constitutive conditions: Constitutive conditions: those that determine something’s identity those that determine something’s identity

19. What makes something a cube? What composition, temperature, etc., are needed to keep a cubical shape? A question for physicists and chemists A question for physicists and chemists A question about enabling conditions A question about enabling conditions

20. What makes something a cube? What properties must a thing have to count as being a cube? A question for geometers A question for geometers A question about constitutive conditions A question about constitutive conditions

21. According to Post-Kantian Philosophy: Geometry cannot be reduced to physics and chemistry Geometry cannot be reduced to physics and chemistry Constitutive conditions cannot be reduced to enabling conditions Constitutive conditions cannot be reduced to enabling conditions Logic and psychology deal with the constitutive conditions of mind Logic and psychology deal with the constitutive conditions of mind Neurophysiology deals with the enabling conditions of mind Neurophysiology deals with the enabling conditions of mind

22. According to Post-Kantian Philosophy: The dualists are partly right: The dualists are partly right: the mind cannot be explained in purely material terms the mind cannot be explained in purely material terms The materialists are partly right: The materialists are partly right: to explain the mind we do not need to posit a non-material component to explain the mind we do not need to posit a non-material component

23. According to Post-Kantian Philosophy: Both materialism and dualism make the same mistake Both materialism and dualism make the same mistake Both assume that if the mind has only material enabling conditions, then it can be entirely explained in material terms Both assume that if the mind has only material enabling conditions, then it can be entirely explained in material terms

24. According to Post-Kantian Philosophy: Materialism says: the mind does have only material conditions the mind does have only material conditions therefore it can be explained in purely material terms therefore it can be explained in purely material terms

25. According to Post-Kantian Philosophy: Dualism says: the mind cannot be explained in purely material terms the mind cannot be explained in purely material terms therefore it must have some non-material enabling conditions therefore it must have some non-material enabling conditions

26. According to Post-Kantian Philosophy: But a cube’s geometrical properties are not additional physical components alongside mass and chemical composition … But a cube’s geometrical properties are not additional physical components alongside mass and chemical composition …

27. According to Post-Kantian Philosophy: Mental phenomena are not non- material enabling conditions in addition to the mind’s material enabling conditions Mental phenomena are not non- material enabling conditions in addition to the mind’s material enabling conditions Mental phenomena are not enabling conditions at all, they’re constitutive conditions Mental phenomena are not enabling conditions at all, they’re constitutive conditions

28. So Are Reductive Materialism & Dualistic Spookiness Our Only Options? No!

29. How does this help with free will? Creatures with minds are made of matter Creatures with minds are made of matter Our physical properties have to be compatible with our mental properties Our physical properties have to be compatible with our mental properties Our physical properties do not have to explain our mental properties Our physical properties do not have to explain our mental properties

30. How does this help with free will? Indeterministic quantum events make free choices possible Indeterministic quantum events make free choices possible They’re enabling conditions of our free choices They’re enabling conditions of our free choices But indeterministic quantum events do not cause or explain our free choices But indeterministic quantum events do not cause or explain our free choices

31. How does this help with free will? Free will “software” can only run on indeterministic “hardware” Free will “software” can only run on indeterministic “hardware” But the hardware is only an enabling condition, not a constitutive condition, of the software But the hardware is only an enabling condition, not a constitutive condition, of the software

32. How does this help with free will? But how do we make the quantum events happen? But how do we make the quantum events happen? By exerting a mysterious soul- force on our component particles? By exerting a mysterious soul- force on our component particles?

33. How does this help with free will? No. No. Free will is not an additional enabling condition – it’s what gets enabled. Free will is not an additional enabling condition – it’s what gets enabled. Our free choices don’t interfere with physical law. Our free choices don’t interfere with physical law.

34. How does this help with free will? Physical law determines only the probabilities of quantum events Physical law determines only the probabilities of quantum events Our free choices don’t alter those probabilities Our free choices don’t alter those probabilities

35. How does this help with free will? Physical law determines how likely the quantum events are Physical law determines how likely the quantum events are We don’t make the enabling conditions more likely We don’t make the enabling conditions more likely We just make the enabling conditions happen We just make the enabling conditions happen

36. How does this help with free will? B But how do our free choices “make the quantum events happen”? y exerting a spooky soul- force?

37. How does this help with free will? No. No. Can you move Can you move an atom without using special equipment? Yes. Just move your hand. Yes. Just move your hand.

38. How does this help with free will? We don’t cause quantum events by exerting a spooky soul-force We don’t cause quantum events by exerting a spooky soul-force We cause them simply by performing the actions which have those events as underlying enabling conditions We cause them simply by performing the actions which have those events as underlying enabling conditions

39. And so the debate continues …

40. The End