Parfit Chapter 12/13 Flashcards
The Physics Exam
- Parfit wants to counter the view that psychological unity implies NR about PI
- someone goes into a physics exam and gets each side of their brain’s hemisphere to do something different
- Parfit shows that” each of these two streams separately displays unity of consciousness” and a person’s mental activity “could be like a river, occasionally having separate streams”
3 options that explain unity of consciousness in the Physics Exam + their responses
- There are new persons: “On this interpretation, the whole episode involves three people, two of whom have lives that last for only 10 minutes”
- One of the calculations is being done by me, the other by someone else
- Both streams of consciousness are being had by me: “We cannot explain the unity of either set of experiences by claiming that these are the experiences I am having at this time, since this would conflate these two sets”
Solution to the physics exam
Reductionism can say that what unites our experience is “a single state of awareness”; there is no need “to explain unity by ascribing these experiences to the same person”.
My division and its possible outcomes
The argument is used to show that PI is not what fundamentally matters in survival
1) P does not survive
2) P survives as one of the two people
3) P survives as the other
4) P survives as both
My Division, answers to 1)
People have survived with half their brain destroyed, so Parfit must survive my division; double survival cannot be a failure
My Division answers for 2)
There is no rational basis for choosing one twin over the other
My division answers to 4)
One possibility: “[the operation’s] effects is to give me two bodies, and a divided mind”. But if these two people Went to live at the opposite end of the Earth, they would meet again and not be able to recognise each other (and play tennis!)
Solution to My Division
On the R view, none of the possibilities discussed in My Division are true or not true. “These claims are merely different descriptions of the same outcome”; the two resulting people will be psychologically continuous with P - in the end, the matter of P being either Lefty or Righty is and EMPTY question
And so PI IS NOT WHAT MATTERS IN SURVIVAL
How ought we regard My Division?
“We ought to regard division as being about as good as ordinary survival”. P’s relation to lefty and righty contains everything that is needed for ordinary survival. We cannot insist that division is like death, because it would be like being someone who “when told of a drug that could double his years of life, regards the taking of this drug as death “.
What matters?
My division shows that P cannot easily argue he persists through time; it also shows that each twin is psychologically continuous with him. Parfit’s view of PI = R + U (where R is Relation R and U is uniqueness - no one can encounter someone qualitatively identical to themselves) U is negligible, so R is what matters. R is conserved in My Division.
15 marker structure
- P wants to say PI is not what fundamentally matters
- short recap on my division and the outcome
- then we need to examine whether the formula works on the physical criterion (since the formula’s strength depends on the psychological criterion’s strength) Pi = B + U
- NR and dualists want to say My Division is as bad as death
- Kagan for NR: P’s experiments fail to give an accurate view of what is meant by PI
- MBIT gives support for P (because it embraces empty questions) physicalism holds that everything is subject to change = indeterminacy. Use Callous Neurosurgeon experiment to show this indeterminacy.
- Kant says “soul counting” isn’t possible
- Swinburne replies individuation of souls isn’t the same thing as what constitutes souls being numerically different to each other + argues that P’s formula doesn’t work + even if SEEs can’t be verified, the concept isn’t meaningless - that would be appealing to verificationism, but absence of evidence not equal to evidence + souls are immaterial so no empirical traces left anyway
- Swinburne on why the first two options of my division are possible + Parfit’s possible rebuttal
- P argued that consciousness doesn’t presuppose a first person nature of the mind, as NRs believe. We can be bundles of thought + can’t discern SEEs through intuition (we are only aware of psychological continuity) example of the Replica (snow case) on Mars
- can’t assert SEEs through deduction (Descartes and Lichtenberg)
- NR on reincarnation which shows that you can have a continuity of quasi-memories not generated in the brain = SEE. Prof Stevenson and Gopal
- P counter that split brain experiments show you can have a divided stream of consciousness - 2 unities not 1
- Kagan points out that SEE don’t seem to matter if they are scrubbed clean of memories in reincarnation (loss of “personhood = ordinary death)
Kagan arguing for NR
P’s experiments fail to give an accurate view of what is meant by PI. SEE = indivisible and immaterial so can’t be subjected to “branching” cases, but P relies on these to develop a formula + define PI in terms of uniqueness. Need for “U” is problematic itself - P makes it to Mars in simple teletransportation, but doesn’t in the branch line case. But the facts of each teletransportation are the same - he is replicated in each case. In My Division, P survives when one half of his brain is implanted, so it’s absurd that he wouldn’t survive if both halves are implanted. On an NR view, these problems don’t apply because immaterial souls cannot be divided and replicated
Swinburne on making P’s first 2 options possible
1) no reason why P couldn’t survive as Lefty or Righty, P seems to concede this
2) if PI = B/R + U, lefty and right can’t logically be P, since the formula requires uniqueness - and uniqueness is not carried through in My Division
3) given (1), it follows that Reductionism is false
P response to Swinburne’s argument
Parfit might say what is meant by his formula is not an analytic truth, but it is metaphysically necessary since the formula ends up being what “PI” refers to. Similarly, water = H20 is not an analytic truth, but once we look at the essence of the word’s reference, we see that water must be H20 in any possible world (it is metaphysically necessary) so Swinburne’s argument is false.
