That reasoning goes farther: What existence do you imagine you have apart from your car, apart from your neighborhood, apart from East Timor or Jupiter? The whole unity is "you."

I sometimes notice how much my environment is a part of my personality. I get to a different environment and some of my habits change, simply because the objects I used for my old habits are no longer there.

>Your brain isn't "you" in some special way that the rest of your body isn't.

Well, in some way it is, in that they can cut your hands and feet, and you'll still be you.

And perhaps if they could just put your head/brain in a jar, and you were still coscious, you'd still consider yourself you...

If my brain was in a jar, but all my sensory perception linked to a robot body on the other face of the planet (without my brain knowing), I would probably consider that robot body me.

And if someone managed to build a model of the human brain and "uploaded" your brain into it such that it acted identically to your biological brain, would you also consider that "you"? Are there two of "you" now?

Note: I'm not disagreeing with you, just kind of following the road your comment lays out.

Short answer: yes, as long as I'm unaware I'm an upload.

I was mostly trying to make the point how much of our existence is rooted in our senses. Even though we can meditate/daydream/dream/etc, most of it processes experiences already had.

I have no idea how a brain without any I/O would contemplate its existence, but I don't think our current psychological models apply.

Don't put too much emphasis on "you" there...the two will diverge quickly. :-)

Without any of your senses intact, what would your consciousness even mean?

You couldn't even sub-vocalize your thoughts. I don't think the experience would be anything like what you're used to as "consciousness."

The brain still might fire its synapses, but I don't see any reason to believe "consciousness" can exist in a brain removed from a body.

Or if they slice your brain down the middle in put it in two different jars, would they both think of themselves as you?

Then, if you keep carefully cutting small bits off of those hemispheres, when would they stop being you?

>would they both think of themselves as you?

If they both continue to think, yes.

>Then, if you keep carefully cutting small bits off of those hemispheres, when would they stop being you?

When they lose consciousness?

If consciousness is a continous property (which is what I believe it is) and not a discrete one, a precise answer would be difficult. The same way you can loose some visual ability but not all.

Or to use the usual philosophical questions, what is it like to be:

- A human brain in a human body

- A human brain not in a human body

- Half a human brain

- Some smaller portion of a human brain

I don't think "is me" / "isn't me" is a clean dichotomy. As you lose parts of your brain you're still somewhat you but you're less you than you were.

> The whole unity is "you."

Why don't you aware of each and every neuronal spike, movement of neurotransmitters and so on?

Yeah, I wouldn't be at all surprised to find out, some day in the far future when we actually understand the human body properly, that we're doing all sorts of interesting processing in the peripheral nervous system and even chemically outside of nerve cells.

We already have hormones and signaling coming from other organs, and those react to other hormones and signaling, so thats possible. I ahve the feeling focus has been put on fast communication of states (potential in the synapses, neurotransmitters) but we know also about slower processes (astrocytes energy management) that also impact brain function deeply, so I would clearly not rule peripheral impact out.