"Since the brains are identical, there is something else independent of the brain that must be contributing to selfhood."

So, you have two brains (the original and the duplicate) possibly thinking in identical ways. The "selfhood" requirement is an appendage you stuck on.

As RFM'er Kimball said:


I've been to a vast many places in my mind, but I've never managed to leave my head.

Considering it's a proven fact that our thoughts and memories exist in the neural networks of our brains, I seriously question the theory that there exists a spiritual consciousness that is both so disconnected from physical reality as to escape all scientific detection, and at the same time so intricately connected with physical reality as to intertwine itself with and manipulate the very neural networks that make us who we are. Sorry, not buying it.

"Considering it's a proven fact that our thoughts and memories exist in the neural networks of our brains, I seriously question the theory that there exists a spiritual consciousness that is both so disconnected from physical reality as to escape all scientific detection, and at the same time so intricately connected with physical reality as to intertwine itself with and manipulate the very neural networks that make us who we are. Sorry, not buying it."

Forget for a moment about "spiritual consciousness" and focus on just consciousness. Surely you do not doubt that consciousness is real. You are a conscious being right? Now, science has confirmed that mental effort can alter brain states by numerous studies. So, if you insist that the mind is not "so intricately connected with physical reality as to intertwine itself with and minipulate the very neural networks that make us who we are," then you are pushing against modern science and specifically brain plasticity arising from mental effort.

You'd have two individuals momentarily identical and then diverging as the brains experienced different input.

I see no need to postulate some ghost in the machine.

All you have to do is look at identical twins, they start from the exact same genetic code, same brain blueprint, but the moment the zygote splits they experience (maybe imperceptivly) different stimuli, and environmental input. Same brains, different outcomes



Edited 1 time(s). Last edit at 12/07/2013 09:12AM by ladell.

Can a spirit be observed, measured, sampled? If it can't be verified, it's just an idea.

And two brains are never identical. Once you start learning stuff, you make connections, and set up neuropathways. The brain isn't set in stone. It changes throughout your life in response to your health and your activities.

There are no identical brains, what is he talking about? Not even twins are born with identical brains. And even if there were two identical brains they would not somehow be magically connected to one consciousness according to ordinary understanding of physics. It's not their level of similarity but the fact that these two nervous systems aren't physically connected that explains that each experience it's own consciousness.

http://exmormon.org/phorum/read.php?2,1100318,1100717#msg-1100717

See the third paragraph.

Okay, thanks. To answer his thought experiment. I do not for a moment believe that my consciousness would be resurrected by such a machine, that would be two clones of me each experiencing their own consciousness. My consciousness depends on the continuity of the physical existence of my nervous system. Sure every atom in my nervous system can be gradually replaced with another atom, but destroy them all and build up a replica, as far as I'm concerned, I'm dead, that's a clone that will go around thinking it is me and that he has resurrected.

I doubt having identical brains would be enough to have identical thoughts. Everything would have to be identical. Even the positions of the electrons around an atom may have an affect on exactly when a neuron fired. Even the input to the brain would have to be identical meaning the two brains would have to exist in bodies that occupied identical locations in space, consumed identical resources (to maintain identical body chemistry) etc.

In the hypothetical everything was structually identical for that moment in time when the transition occurred creating the twin. But you do raise a good point. Perhaps selfhood is a function of a perception of the body in a particular space and time. In in the hypothetical even at the creation moment they would not be in the same place. However, suppose that their sensory apparatus were disengaged momentarily, such that all they had mentally at the moment of creation was a bare psychological state. Would the twin have any sense of self at that point. Perhaps not. But it seems to me that the underlying sense of self from a physicalist perspective requires more than just one's position in space (and time); i.e. it requires more neurological structure.

Your "electrons around an atom" point brings in quantum mechanics. But neuroscientists generally believe that brain function can be classically described despite its underlying QM properties.

CP and stroke patients work hard to rebuild pathways in the brain. Parts of anyone's brain can be built up or left to deteriorate.

We see people work at building muscle. With effort they can also build critical thinking or other brain skills.

"So, you have two brains (the original and the duplicate) possibly thinking in identical ways. The "selfhood" requirement is an appendage you stuck on."

No. "Selfhood" is an acknowledged psychological state which neuroscience believes has a correlated brain state. Most believe that it arises as a result of the brain mapping the body in conjunction with historical enviromental input. Moreover, surely as you reflect on your own psychology you have a sense of self.

In the thought experiment, I placed emphasis on the moment in time which two identical brain structures were producing two identical instantiated "selves." What is still needed is a mechanism that differentiates one psychological self from another. But if the brain states are identical, hypothetically the psychological states are also identical. So where would the differentiation come from?

Note: Some suggested that the brain states would thereafter evolve separately, and perhaps generate different selves through such evolvement. But that misses the point.

You seem to be defining selfhood as a sense of self. I don't know how you define self. But, if a sense of something is awareness, then you've answered your own thought experiment.

deleted.



Edited 1 time(s). Last edit at 12/07/2013 06:40PM by thingsithink.