[brittonrt]

This brings me to an interesting thought experiment I struggle with:

Most likely most people here would agree that if you make an exact copy of a person's brain, whilst leaving the original intact, it would be a new person, identical but divergent from the original. A new thread of consciousness by such definition.

But then, what if you destroy the original at the moment of copy? It would appear to the same.

But then, what if you replace each neuron one at a time over a period, maintaining the original network? This question is troubling because it brings into obvious doubt the integrity of our notion of consciousness. As it is in fact the case that we shed most of the atomic matter that constitutes us in a given year, we are clearly immaterial. Patterns.

So put plainly: should you copy your brain all at once, killing the original, are you a new person? But if you are: transitioning slowly piece by piece over time, which is what we observe in nature, this maintains the conscious strain? How are these different?

It's obvious to me there is something fundamental here we are missing. I welcome any insights you all might have had in similar thought experiments.

[dghf]

You seem to be assuming the actual existence of a "thread of consciousness" or a "conscious strain", when it could be an illusion.

When you wake up after a dreamless sleep, are you the same person, the same conscious entity, as went to bed the night before? Or is that entity now "dead", and "you" are a new entity that has just inherited its memories (most of which it in turn inherited from its predecessors)? How could you ever tell? In fact, are you the same conscious entity from moment to moment, or at least from thought to thought?

More "making a copy" thought experiments, none terribly original:

- If you're disintegrated and immediately reassembled, are you still you?

- Does using different atoms make a difference?

- Does leaving a gap between disintegration and reassembly make a difference? If so, how long a gap? What if you're resurrected at the Omega Point by sufficiently advanced aliens/post-humans?

- If you're split in two (sagitally, coronally, or however), and each half is immediately reconstructed into a whole human, each identical to you before the split, which is you? Which pair of eyes would you find yourself looking out of? Both? Neither?

- If the two "yous" exchange atoms, such that one ends up with the entire complement of atoms that made up you before the split and the other ends up with none, does that affect the claims of either to be the "real" you?

[brittonrt]

Excellent points, and actually in line with my line of question as well: I think my assumption of a thread of consciousness was a semantic mis-communication, as bringing that idea into question was indeed where my questions were leading.

[grumio]

Several philosophers have attended to those very thought experiments. I recently read some of Locke's "Essay Concerning Human Understanding" (Book 2), and he has some interesting thoughts on person-hood and persistence of consciousness in chapter 27.

[coconutrandom]

The second question is the same as The Ship of Theseus.

http://en.wikipedia.org/wiki/Ship_of_Theseus

[eli_gottlieb]

There's nothing fundamental we're missing: the reality beneath our intuitive understanding of personal identity and continuity is just a lot messier than our intuitions allow for. Nondiverging copies are, in some sense, the same person, but they're also completely useless: the instant you "wake them up", they diverge and become different people. Destructive "moving" preserves personal identity, but is goddamn creepy because it provides no way for the "moved" person to verify that they remain the same before-and-after. The "continuous stream of consciousness" model is intuitive and lets us detect when something in our heads changes (you can feel yourself going from "sober" to "drunk" while awake in a very different way than if I just injected you with booze while you slept... For Science, of course).