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Why Do We Stay the Same Person Over Time? Why Not Split Up?

It would be a total fluke if all the different clouds of atoms that produce your brain would always produce the same consciousness. But they do

In the third podcast of the series, “Unity of Consciousness,” Walter Bradley Center director Robert J. Marks interviews Angus Menuge, professor and chair of philosophy at Concordia University, on unique features of human consciousness, including the fact that our experiences are a unity, despite being scattered across many brain regions and even if our brains are split in half: But now let’s do some thought experiments, as proposed by Oxford philosopher Richard Swinburne:

This portion begins at 04:55 min. A partial transcript, Show Notes, and Additional Resources follow.

Angus Menuge: There’s another problem raised by [philosopher] Richard Swinburne:

He imagines that he’s going to have an operation where each of his cerebral hemispheres is placed in another person. So you’ve got to think that there are two other people. One of them has a missing left hemisphere. The other one has a missing right hemisphere. Your left hemisphere goes into the first one, your right into the other one. Well, they are continuous with the original you. And so it would seem that if you based identity on continuity, they both have to be you.

Note: Richard Swinburne, an Oxford philosopher, is the author of Are We Bodies or Souls? In response to those who think that we are merely complex machines or conscious animals, he presents new philosophical arguments.

Angus Menuge: But they can’t both be you because two things cannot be one thing. The options really are either that you don’t survive at all or you survive as one of them rather than the other one, but you can’t survive as both.

Well, the problem is that we see that someone can continue to be conscious, even though their brain is being changed by an operation or something has been added to it. And yet they’re the same consciousness.

Note: Neurosurgeon Michael Egnor has considered a comparatively simpler transplant situation of “transplanting an eye and the parts of the visual cortex it needs from one person to another.”

Based on what we know now, “We tend to assume that there must be a medium of communication both between our eyes and our whole brain in order to see. But people who have had split brain surgery see quite well even though their hemispheres have been separated (thus there is no direct connection). If the eyes (and hemispheres) are separated by 4000 miles, would the principle be any different? On this view, we see where our eyes are, not matter how far they are apart.

“This sounds strange, but it’s not really. Our eyes are already separated by about 4 inches (10 cm), which is what gives us depth perception. With transplantation, our eye separation would be variable and much greater. So Jack wouldn’t be able to fuse the different images and thus would have double vision.” – What If Only Part — Not All — of Your Brain Were Transplanted? Mind Matters News

It’s a thought experiment, intended to underline the importance of the fact that a whole visual system is a means of perception, not simply a function. And a self must perceive, if anything does.

Angus Menuge (pictured): Secondly, over time, your brain — from the point of view of physics — looks mostly like a cloud of particles. And yet you remain the same person.

Or here’s a difficulty: There are many candidates for the brain that could generate consciousness at one time. So in other words, your whole brain, or many, many subsets of it would all be sufficient according to materialism to generate consciousness. Then why aren’t you many consciousnesses at one time? Likewise, if your brain is a constantly changing cloud of atoms with bits of matter being added and removed all the time, why don’t you keep changing from one consciousness to another?

In other words, why do we even stay the same person over time at all? It would be a total fluke to say that all these different clouds of atoms would always produce the same consciousness. Whereas if you take the simple view — there’s something constant, you have this one soul, at and over time. And that explains why you are one consciousness at, and over time.

Physicalism [physical nature is all there is] seems to implausibly predict that you should be many consciousnesses at one time and many over time. And this is just not what we observe.

Next: Life in the plural: If there were two of you, would “you” exist?


Here are the earlier portions of this discussion:

Part 1: Mystery: Our brains divide up events but we experience them whole That’s one of the conundrums of consciousness. Philosopher Angus Menuge notes that something that is not just our brains unifies our experiences from the partial information scattered across many neurons.

Part 2: How split-brain surgery underlines the unity of consciousness. At one time, some thought that if the brain were split, consciousness would be too, but that did not turn out to be true. Philosopher Angus Menuge thinks that “split personality” doesn’t mean two consciousnesses but loss of access to the information that integrates mental states.

Show Notes

  • 00:30 | Introducing Dr. Angus Menuge
  • 01:04 | Unity of consciousness
  • 03:04 | Split-brain operations
  • 04:55 | Split personalities
  • 06:49 | Too many thinkers problem
  • 11:06 | Why don’t bodily changes generate a different consciousness?
  • 14:28 | Elon Musk’s Neuralink

Additional Resources

Podcast Transcript Download


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Why Do We Stay the Same Person Over Time? Why Not Split Up?