The document discusses the philosophical problem of personal identity and how identity persists over time despite changes to our bodies and minds. It uses examples like the Ship of Theseus, where all parts of a ship are gradually replaced, to illustrate this problem. It also considers cases like a professor transitioning gender or a musician changing his name and disavowing his past work to question what makes someone the same person over time. The document reviews proposed solutions to this problem from philosophers like Descartes, Locke, and Hume.

1. Who am I?
The Problem of Personal Identity in
Modern Philosophy

2. The Ship of Theseus

3. The Ship of Theseus
• Suppose the Argo is in continuous service between
Athens and Crete.

4. The Ship of Theseus
• Suppose the Argo is in continuous service between
Athens and Crete.
• As its parts wear out they are replaced with new ones
and the originals are put into storage.

5. The Ship of Theseus
• Suppose the Argo is in continuous service between
Athens and Crete.
• As its parts wear out they are replaced with new ones
and the originals are put into storage.
• Eventually all of its parts are replaced.

6. The Ship of Theseus
• Suppose the Argo is in continuous service between
Athens and Crete.
• As its parts wear out they are replaced with new ones
and the originals are put into storage.
• Eventually all of its parts are replaced.
• There are now two ships – one that has been sailing
back and forth every day and one in parts in storage.

7. The Ship of Theseus
• Suppose the Argo is in continuous service between
Athens and Crete.
• As its parts wear out they are replaced with new ones
and the originals are put into storage.
• Eventually all of its parts are replaced.
• There are now two ships – one that has been sailing
back and forth every day and one in parts in storage.
• If the parts are reassembled which one is the Argo?

8. The Problem of Personal Identity

9. The Problem of Personal Identity
• What makes ME one and the same person in
spite of all of the physical and psychological
changes that occur to me?

10. The Problem of Personal Identity
• What makes ME one and the same person in
spite of all of the physical and psychological
changes that occur to me?
• Is there an underlying source of my identity
as one and the same person?

11. The Problem of Personal Identity
• What makes ME one and the same person in
spite of all of the physical and psychological
changes that occur to me?
• Is there an underlying source of my identity
as one and the same person?
• If so, what could it possibly be?

12. Who am I?

13. Who am I?
• A kid in the 1970’s?

14. Who am I?
• A kid in the 1970’s?
• An adult in the 2000’s?

15. Who am I?
• A kid in the 1970’s?
• An adult in the 2000’s?
• An old man in the 2040’s?

16. The Case of Professor McCloskey

17. The Case of Professor McCloskey
• Donald was an economics professor.

18. The Case of Professor McCloskey
• Donald was an economics professor.
• But he had another person inside – Dee.

19. The Case of Professor McCloskey
• Donald was an economics professor.
• But he had another person inside – Dee.
• But he was still Donald.

20. The Case of Professor McCloskey
• Donald was an economics professor.
• But he had another person inside – Dee.
• But he was still Donald.
• Until the operation turned him into her –
Diedre.

21. The Case of The Folk Singer

22. The Case of The Folk Singer
• There once was a man named Dmitri
Georgiou.

23. The Case of The Folk Singer
• There once was a man named Dmitri
Georgiou.
• But he called himself Cat Stevens and
recorded a bunch of cheesy folk music.

24. The Case of The Folk Singer
• There once was a man named Dmitri
Georgiou.
• But he called himself Cat Stevens and
recorded a bunch of cheesy folk music.
• Until he almost died. Then he became Yusuf
Islam, and disavowed all of Cat Stevens’
music.

25. Descartes’ Solution

26. Descartes’ Solution
• Minds and bodies are essentially different
kinds of substances – we know this because
we can doubt the existence of bodies, but not
of minds.

27. Descartes’ Solution
• Minds and bodies are essentially different
kinds of substances – we know this because
we can doubt the existence of bodies, but not
of minds.
• Minds are simple, indestructible substances.

28. Descartes’ Solution
• Minds and bodies are essentially different
kinds of substances – we know this because
we can doubt the existence of bodies, but not
of minds.
• Minds are simple, indestructible substances.
• What makes me me is the persistence of this
immaterial thinking thing.

29. Locke’s Solution

30. Locke’s Solution
• The idea of a self is the idea of something “we
know not what” underlying and unifying our
experiences.

31. Locke’s Solution
• The idea of a self is the idea of something “we
know not what” underlying and unifying our
experiences.
• Consciousness and memory together provide a
basis for saying that one and the same person
persists through all of the physical and
psychological changes that person goes
through.

32. Hume’s Doubts

33. Hume’s Doubts
• If all ideas must come from impressions, we
have no idea at all of a self, since we do not
ever experience one underneath whatever we
happen to be experiencing.

34. Hume’s Doubts
• If all ideas must come from impressions, we
have no idea at all of a self, since we do not
ever experience one underneath whatever we
happen to be experiencing.
• Consciousness and memory won’t work
because they are full of gaps.

35. Hume’s Doubts
• If all ideas must come from impressions, we
have no idea at all of a self, since we do not
ever experience one underneath whatever we
happen to be experiencing.
• Consciousness and memory won’t work
because they are full of gaps.
• What we call the self is nothing but a bundle
of impressions and ideas bound together by
the weak ties of association.