Brandeis University, Philosophy Department
Fall 2006
Brandeis University Web Stite

Philosophy 1A

Introduction to Philosophy

Professor Andreas Teuber
Prof. Teuber

"Brain Rejuvenation"

Now consider the following: As you can well imagine, philosophers have become especially fascinated by Julia's case. A number of them think Julia's case shows that a person cannot be identified with his or her body, that personal identity is not bodily identity, and that her case is just a fuller and more complete example of the phenomenon each of us has experienced early in the morning upon waking before we have opened our eyes to face the day. Then most of us know who we are before checking our bodies, looking to see if it's our hand, our feet, for examples, that are there with us in bed.

Of course, J/M has only part of Julia's body; J/M has Julia's brain.

But if memories, beliefs, desires and the like are largely dependent on brain states (whether or not they are identical with them), it is not so surprising to find that post-operative Julia remembers things that pre-operative Julia did, that post-operative Julia is, with respect to Julia's psychological characteristics and personality generally, like pre-operative Julia, in spite of her physical appearance and her fingerprints.

In light of these observations some philosophers believe that it is not just having pre-operative Julia's brain that incline them to take post-operative J/M to be Julia North rather than as Mary Frances Beaudine, but what the brain, as it were, brings in its wake. For these philosophers what's crucial, is the information and memories and psychological attitudes and beliefs that Julia's brain harbors and contains.

Indeed this episode in late twentieth century medicine has helped to revive the John Locke Society which had fallen on hard times in the late 70's since it was John Locke (1632-1704) who thought that personal identity consisted in links of memory or as he might put it, "our ability to extend our consciousness into the past." Julia's case seemed to vindicate Locke and membership in the Locke Society has increased ten-fold since Julia appeared at her press conference and helps to explain why John Locke T-shirts are so popular.

There are other philosophers, however, who believe that John Locke could not have been right. He was, after all English and a rather plodding and methodical thinker, if much of a "thinker" at all, and they find it odd that Locke should be given credit for much of anything, let alone having so much as a "thought."

Locke's view that our identity over time must have something to do with psychology and that memory played no small role in underwriting a psychological approach to personal identity has not - as you can well imagine - been immune from criticism. A chief critic, early on, was Thomas Reid (1710-1796).

As a result the Thomas Reid Society has enjoyed a bit of a renaissance, sending out copies of relevant passages from Reid's work wherein Reid argues that memory as a criterion of personal identity faces two problems.

The David Hume Society has also gained some new members due to the work of such contemporary philosophers as Dan Dennett who has revived Hume's suspicion that we are "a bundle or collection of different perceptions" rather than a singular substantive entity. This has led to the highly successful marketing of a very popular David Hume "bobble-head" by Bobble Head World Inc.

Brain "Rejuvenation" Cases: To complicate matters a bit further, rumor has it that Dr. John Matthews has been working all these years on a new process and that he is about to perform another operation on Julia. He is apparently living somewhere in and around Seattle.

Did I mention that Julia moved to Seattle after her trial?

Some say that Dr. Matthews is carrying out his research on the grounds of Microsoft Corporation and that his most recent research is being funded by none other than the Bill and Melinda Gates Foundation which recently received an infusion of cash - you probably know - from Omaha's Warren Buffett.

Dr. Matthews has apparently developed a technique of brain "rejuvenation" or brain "revitalization," as he calls it. It is a technique which allows him to replace a person's brain with an exact duplicate, neuron by neuron, blood vessel by blood vessel, artery by artery. What's critical is Dr. Matthews' discovery of a method of preserving all the information, memories and psychological attitudes and beliefs that a person had before the "rejuvenation."

Did I mention that Julia has developed weakening of the arteries and she fears a stroke like that which killed Mary Frances?

The brain "rejuvenation" operation, rumor has it, is scheduled to take place the first weekend in August somewhere in Seattle.

Will the new person be Julia? What do you think?

If information and psychology are what's crucial in determining personal identity, what difference should it make if this or that artery is not the same artery or whether pre-operative Julia has the same specific neurons as post-operative Julia? Or whether they are "squishy" and "cellular" or made out of "gortex?"

All that should matter is the information and the patternings and the memories, no? And post-operative Julia will have all of THAT, all of the information and memories that pre-operative Julia happened to have. And if memory is the key to personal identity, "a past being is you if and only if you (you now) remember experiences you had then." Julia with the "rejuvenated" brain will remember what pre-operative Julia did and so should be Julia, no?

Most members of the John Locke Society - or so one might think - would have to believe that post-operative Julia is one and the same person as pre-operative Julia, no?

Brain "Psychological Information Extraction" Cases: What do you think of the following put forward by one member of the John Locke Society?

Imagine that Dr. Matthews has perfected a technique to "extract" the information (memories and psychological attitudes) from a person's brain, to store it for a couple of weeks and then be able to put it into someone else's nervous system whose brain had been "wiped clean," as it were, of all its mental content, memories and information.

"Wouldn't we have to agree," this member of the Locke Society said, folding his arms across his chest and looking rather pleased with himself, "that this person was the same person whose information had been 'extracted' and 're-introduced' into the person with the 'clean' brain?"

What do you think?

Julia-A and Julia-B (Fission or Branch-Line) Case: Imagine that in the early stages of his brain transplant research Dr. Matthews was not yet able to remove an entire brain from any one person's body, but developed a technique to remove one hemisphere at a time. Imagine, too, that it has been established that a person not only can survive with one hemisphere of their brain intact but that such a person has all the memories and psychological attitudes and beliefs of the person with both hemispheres prior to the removal of just one hemisphere. Dr. Matthews thought of this operation on the heels of the work by Roger Sperry, who received a Nobel Prize in 1981 for his "Split Brain" Experiments.

Play "The Split Brain Experiments Game".

As a "cure" for epilepsy
the corpus callosum connecting
the two hemispheres is cut.

Imagine that an early version of brain transplantation involved the transplanting of a person's left hemisphere into the body of another person and of that same person's right hemisphere into the body of some third person.

Imagine that instead of transplanting Julia's brain into Mary Frances Beaudine's body, Dr. Matthews transplants Julia's left hemisphere into someone else's (brainless) body and Julia's right hemisphere into, say, the body of some third person's (brainless) body. Call the persons who result from this operation: "Julia-A" and "Julia-B." Both beings survive and both remember events that took place in Julia's life, i.e., both have Julia's memories and Julia's character and attitudes.

See "How Can Someone Live with Only Half a Brain?"
in a recent issue of THE NEW YORKER, July 3, 2006.

Both Julia-A and Julia-B remember, for example, sailing on Puget Sound last weekend - Julia went sailing on Sunday - and both remember Julia's childhood experiences in San Francisco. They also both remember how much they love Julia's favorite foods, how much they "love" broccoli - the dietary habits of the elder George Bush notwithstanding - and how much they love peanut butter and raspberry jam sandwiches on white bread.

So, imagine that the operation is a success. Julia-A and Julia-B survive. What happens to Julia?

There seem to be only three possibilities. Which is true?

(1) Julia does not survive.
(2) Julia survives as Julia-A or Julia-B, but not both.
(3) Julia survives as both.

What's your view?

Does your "theory" of personal identity in the brain transplantation case fit one or another of the above possibilities?

If so, does it still seem to be a reasonable "theory" to hold or do you (now) find yourself in a position of having to revise or abandon the "theory" you developed to explain who killed Jack?

How does the "theory" of personal identity that you developed to "explain" your conclusion in the brain transplantation case square with your conclusions in the brain rejuvenation, brain information extraction and fission (branch-line) cases?



[PHIL 1A] [Syllabus] [Handouts] [Home] [Bio] [CV] [PHIL DEPT.] [E-MAIL]

Send comments to: Andreas Teuber
Last Modified: 10/13/06
Instructor's Toolkit
Copyright © The President and Fellows of Harvard College