X-Message-Number: 25308
Date: Mon, 13 Dec 2004 08:30:43 -0800
Subject: Brains & Minds, to Francois
From: <>

Dear Francois:

You are thinking more clearly about this issue, but there are still 
many errors that must be handled in due course.


You wrote:

"3- Human brains manifest a behavior we call mind. It's not the 
only thing they do, but it's the one that is of interest in this 

Let me be very clear on this point: minds do not exist; they 
happen, by which I mean that 'mind' is a word used to describe a 
type of change that occurs to human brains.

The brain does indeed exist, but the changes to a brain that we 
call 'mind' (what you call the behavior) do not exist.

You rightly concede that two brains are not the same brain, even if 
they have the same atomic arrangement (Thomas denies this). 
However, you say that two minds can be the same, even if they 
happen to different brains, and that this sameness is a guarantee 
of survival in case of duplication or uploading.

These are two separate claims, so I will analyze them individually.


If two minds are the same mind, then they share all properties, 
which is to say that a property X is a property of one mind if and 
only if it is a property of the other.

Now minds are not things that exist, but rather, things that happen 
to a brain. So to say that minds M1 of brain B1 and M2 of brain B2 
are the same mind is to say that the mind-related changes of B1 are 
identical to the mind-related changes of B2, over the period in 
which they are the same. After some consideration you will easily 
see this implies that B1 and B2 are physically identical over the 
period of sameness.[1]

Since mind-related changes occur over a non-zero time scale, it 
therefore only makes sense to talk about minds being the same over 
lengths of times equal to or greater than the minimum time scale at 
which mind behavior is exhibited in a brain.

Due to both quantum and chaos theory, this implies minds can never 
be the same. The changes that occur to one system cannot be exactly 
the same as the changes that occur to another system, even if the 
systems start with the same atomic arrangement.

More troubling for the uploader, since it is meaningless to compare 
changes to a brain to changes to a non-identical brain, it is 
therefore impossible to compare the mind of a human brain with the 
'mind' of a CPU.

Let me summarize these results as follows:

1.1: Two minds can be compared to each other only over the positive 
timescale in which minds happen to a brain (contrast this with 
brains, which can be compared only at a given instant, at least 
conceptually, if not in reality).

1.2: Two minds can be compared to each other only if they happen to 
brains that are physically identical; it is meaningless to compare 
changes to a CPU with changes to a brain, or even changes to one 
brain with changes to another (different) brain.

1.3: Minds can never be the same, since 'mind' is a change and 
quantum theory implies that even two physically identical systems 
will proceed along different paths, while chaos theory magnifies 
these differences.

By now your foundations are sufficiently weak that you cannot 
support your conclusion that duplication and uploading result in 
survival. However, I will go one step beyond this. Let us assume 
for a moment that two brains are perfectly synchronized over large 
time scales, so that we can say the two minds that happen to the 
brains are actually the same mind, which reduces to merely saying 
the brains are changing in the same way, and that these changes are 
of the type we call 'mind'. I will now proceed to the second claim.


We are assuming that two brains exist, which started with the exact 
same configuration, and continue to evolve in exactly the same way, 
such that we can validly say, 'Both brains have the same mind,'---
i.e. the mind-related changes that occur to one are exactly the 
same as the mind-related changes that occur to the other.

Let's assume one of these brains is mine. In order to address the 
question of whether 'I' survive if one brain dies, it is necessary 
to describe what exactly 'I' am.

The statement 'I am a mind,' without regard to a brain, is 
meaningless, because minds do not exist; it is equivalent to 
saying, 'I am this kind of change [divorced from a medium of 

The only meaningful expression of 'me' in terms of a 'mind' is as 
follows: I am the mind that happens to this brain; in other words, 
I am the mind-related changes that occur to this brain. 

If I am the mind that happens to this brain, then if this brain is 
destroyed, my mind can no longer happen to it, so my happening 
ceases, and I do not survive---my subjective inner life stops 

The fact that there was a physically identical brain changing in 
the same way as my brain was changing is utterly useless from the 
perspective of my survival, since I am not merely a 'change', 
abstracted away from the physical universe, but a change to a 
specific hunk of matter, which, when destroyed, can no longer 
change in ways supportive of my subjective inner life.

Let me summarize these results as follows:

2.1: It is meaningless to say 'I am a mind,' as if such a thing can 
exist; the only way your subjective inner-life can be expressed in 
terms of a mind is to say, 'I am a mind that happens to this brain.'

2.2: If my brain is destroyed, then I no longer happen, since I was 
the mind that happened to my brain. Consequently, duplication 
cannot result in survival.

I think I have made it quite clear that not even (impossibly 
precise) duplication can result in personal survival. It simply 
cannot happen, because 'minds' and 'processes' and such do not 
exist. Brains do. When your brain is destroyed, your subjective 
inner life ends.


Best Regards,

Richard B. R.

[1] This does imply mind-sameness is impossible given the laws of 
physics, but I don't wish to go over the arguments here.

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