Lecture 9

Personal Identity

Topics for this lecture: • The body theory, which leads to• The brain theory• The soul theory• The psychological theory, which leads to• The memory theory, which leads to• Shoemaker’s quasi-memory theory• Let’s try division/fission

The Notion of PI• The idea of personal identity over time.

• You were at last week’s lecture; you once were 5 years old. That is, there was some person that was you, back then.

• Some student will be whipped next week in thelecture.

• It will be you! A new set of emotions….

• Distinguish criteria of identity (what it consists in ) from evidence of identity.

Basic 3 views on PI

• The body theory. This can become the brain theory, which is slightly more restrictive.

• The Soul view, or the ‘simple’ view.

• The psychological view.

The body theory

• One can survive transplants … knees… other body parts…

• But what about a brain transplant?

• Shoemaker’s ‘Brownson’ case.

• So… we arrive at the theory that you need your brain to survive.

The Brain Theory

• But…

• Bernard Williams’ Brain State Transfer Device’.

• If so, the brain is no different from a leg.

• So… the brain theory is problematic.

The Soul/Simple View

• Idea that PI is irreducible.

• But:

• The knowledge problem. (See Perry.) On this view we could never know abut PI, either in others or even in our own case.

• Maybe our souls are changing every 5 minutes…Maybe there are 100 souls in my body all thinking the same thoughts?!

A Methodological Consideration…

• Question of what is important in survival (Recall a similar question that Dennett asks about free will.)

• Why do we want to survive… the plane trip …? It seems… we care about, our thoughts, plans, character, … continuing…

• We want the stream of consciousness to flow on.

• The physical (body & brain) and soul theories do not explain why we want to retain the same body or soul… except insofar as our psychological life goes on… is retained.

• We wouldn’t care about retaining the same body or soul if our psychological life did not flow on.

The Psychological Theory

• Hence the idea that PI consists in psychological continuity is attractive.

• For it answers the valuing/caring criterion… that it explains why we might care about or value PI in the way we do.

The Memory Theory

• One version of the Psychological Theory is : the Memory Theory.

• Chains of memory relations. The general can remember being a soldier who can remember stealing apples as a child.

• (Fancy diagram here.)

John Locke

• Circularity objection (Bishop Butler of Durham!)

• Shoemaker’s quasi-memory reply.

• Quasi-memories caused in the right way …

A quasi-memory is an apparent memory or a memory experience.

The Bishop

Sydney Shoemaker

• So you can’t remember being Guy Fawkes…

• Mental connectness idea.

• Methuselah’s… long life. Over-lapping chains of mental connectedness.

• But…. Possibility of psychological splitting…

• Tele-transporter case… usually the original is destroyed… would be like a 3D Xerox .. Of you.

• What about split brain cases. (Not merely imaginable, some real cases.) Two hemispheres, each a centre of consciousness.

• Strokes may wipe half brain… half seems to suffice.

• Compare bridges, cities… can divide. …

• But then is survival a matter of degree? Is it black and white?

• Do questions about PI have clear abswers one way or the other?

• Puzzle cases, like the ship of Theseus.

• What matters… links of psychological continuity, we want our mental life to flow on…

• If A splits… into B and C... fission…. Both can claim to be the descendent of A. But it is not the case that B=C. So neither is = with A. (Identity is ‘transitive’.)

Fusion?

• Put two brain in one body and join them. • Better than death?

Again it looks like survival is a matter degree…

But… that is not how it seems from the inside.

So… it is rather perplexing.

A tricky one!

Finally…..

• Next week…. I won’t be here.

• Peter Vickers will finish off the topic of Personal Identity.

Have a good well-earned break after next week and

Good luck with the rest of KR!