Brent, Nick,

On 31 Mar 2011, at 03:06, meekerdb wrote:

On 3/30/2011 3:15 PM, Nick Prince wrote:
In Russell’s book there is a section on “Arguments against QTI”
And I want to put forward some issues arising from this.

It seems that (if MWI is true) we live in world(s) in which we appear
to live a finite, small lifetime of around 70 years.  From the many
discussions on this list, it also seems to me that, this is the single biggest argument (that I can understand) which points to the QTI being
false.  Unfortunately it appears that the whole ASSA/RSSA debate -
which might have been a candidate for clarifying the issue - turns out
to be a confusing (to me anyway) and polarising approach.

So is QTI false?

Russell does put forward a possible solution in his book. He suggests
the idea that as memory fades with dementia then perhaps the conscious
mind becomes so similar to that of a newborn - or even unborn - baby
that perhaps “a diminishing?” consciousness always finds an
appropriate route (in some branch) to avoid a cul de sac event.
(This is one possible form of the No Cul De Sac Conjecture =NCDSC)

Sure, the cul de sac is "avoided" by reaching the state of unconscious which is then consistent with with many more continuations. e.g. as a rock.

I am not sure this makes sense. By definition a cul-de-sac world has no continuation. To be unconscious or dead (never more conscious) means no more experience at all (if that means something).

The QTI is based on quantum theory of unitary evolution; not on the survival of memories or consciousness. Those are claimed to be consequences, so they must be justified from QM, not just promoted from conjecture to axiom.

Assuming comp, QTI should be a particular case of Comp-TI. But this is complex to analyzed for the reason that we can survive ith amnesia, so that we can never be sure of who is the person who really survive. Comp and QM TI might end up trivial if there is only one person in the fundamental reality.

Russell is right. The presence or non-presence of cul-de-sac is a question of points of view.

Precisely we have that G* proves the equivalence of Bp and Bp & Dp. But the machine cannot see that equivalence. The modality Bp entails the existence of cul-de-sac world at each states, and Bp & Dp eliminates those end worlds. People have to go back to the semantic of G or of normal modal logic to see this. In a cul-de-sac world every statements are provable, but none are possible or consistent.

With both QTI and COMP-TI we cannot go from being very old to being a baby. We can may be get slowly younger and younger in a more continuous way, by little backtracking. We always survive in the most normal world compatible with our states. But some kind of jumps are not excluded.


To avoid the cul de sac event, there would surely have to be a
critical  stage whereby  consciousness diminishes and reaches a form
of cusp at the point of lapsing into non existence and thereby
requiring the necessity of an extension route or branch to another
consistent universe.  In short, from the third person POV, the person
dies but from the first person -(now primitive) consciousness – state,
there is rebirth.  I am thinking that before we get to the croaking
Amoeba there is a discontinuity in what we understand as consciousness
– at least the form that applies to the NCDSC.

Now if all this were to be the case, then maybe it says something very specific about the substrate on which consciousness runs. There would
be something special about the architecture which the substrate
employs to implement consciousness because it relies on a certain mode
of decay, facilitating the branching to a new born baby having an
appropriate structure (portal?) to secure a consistent extension of
the consciousness into  another branch.  Unless a computer could
simulate such a special substrate then it could not be used to
implement consciousness. This would mean that it would be wise to say
no to the Doctor! –  Comp might be false?

Comp might certainly be false. But I am not sure I see your point here. There is an infinity of computational histories going through your state. The substrate (matter) is "made-of" that infinity of computations.

The Turing principle (p135 of David Deutsch’s book – “the Fabric of
Reality”) would imply that, a universal machine could simulate the
physical structure of brains in such a way so as to be able to act as
a medium whereby, if the above argument is possible, consistent
extensions of conscious physical observers (persons) could avoid cul
de sacs.

I think that the Turing principle is contradictory with Church thesis. What we can do is to (re)define matter by adding the "& Dp" (= & ~D ~p) in each state. It is needed for defining the first person measure "one" in the case of the first person indeterminacy. matter and physics is a probability/credibility calculus on relative consistent extensions.

But until we can understand the nature of what consciousness
is, we are stumped as to how a computer can be programmed to implement

If you accept the classical theory of knowledge, it is easy. Computer are already conscious. They have not the tools to manifest their consciousness, and by programming them, we don't help them with that respect. Consciousness is not programmable. It exists "in Platonia", and a universal machine is only a sort of interface between different levels of the Platonic reality (arithmetical truth).

However some alien civilizations may have known these techniques
for ages now, thereby perhaps explaining why we each have lived even
as long as we now perceive we have. A stronger statement would be that
if universal virtual reality generators are physically possible, then
they must be built somewhere in some universes!

This is automatically true, even if there are no universe. The arithmetical reality contains the differentiating flux of consciousness, the many dreams. Not sure that the notion of (physical) universe makes a global sense. It is a local reality as viewed from inside. (inside views are defined by the modal variants of Bp).

But supposing the above (reincarnational) speculation was false in
some way. In that case, I have yet to see a convincing argument as to
how the the no cul de sac conjecture can be reconciled with people
living  to great ages.  Whatever sampling assumption is applied, the
facts are that we don’t typically see people reaching ages greater
than 100+ yrs). Therefore either QTI is false or  people just don’t
get old!


QTI and COMP-TI are first person notion, not necessarily first person plural.

Rather, the special physical conditions of death associated
with dementia or oxygen starvation of the brain, facilitate continued
extensions of consciousness by branching into worlds where we
supervene over new born babies (or something – animals, aliens?) -
accidental deaths of people of any “normal ages” we can think about
could of course be accommodated by the NCDSC).

The mechanics of such  reincarnational transitions would be
interesting to speculate about since I see this as the only way out for a QTI

I think your idea are correct here. But they are hard to implement technically due to the use of amnesia. But QTI use comp, and comp force the exact QM to be derived from arithmetic. Only by doing the math can we make precise that type of speculation.


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