On 13 Apr 2017, at 13:35, David Nyman wrote:
On 13 April 2017 at 10:09, Bruno Marchal <[email protected]> wrote:
Oops.
Yet, you asked me about the modal logic, and I do think at some
point I have to say precisely what the G box [] is for. It is
simple, but long and tedious. I hope you have not too much
difficulties with my previous post.
To make this accessible, the universal dovetailer argument can be
seen as a layman version of the "machine interview (the G logics and
its variants imposed by itself). (even if it came befoe in my mind
when observing the amoebas). I replace the machine by a human
willing to be that he is a machine, and the thought experiments
explains the reversal. The G logics makes this precise, and more
abstract/general, but it relies on the extra-ordinary works on
computability and logic of Gödel and others, which are not that
difficult, but is hard to sell without some precision. Don't
hesitate to encourage me to rewrite a passage in some more shorter
way, in case you lose the line.
Thanks for this Bruno. I suppose I ought to say I have some
special interests here. In the first place, my interest is in
understanding what ultimately could justify characterising any
phenomenon as internal, intrinsic, or subjective; IOW what is called
1p in this forum. The reason is that I think this is an extremely
under-examined, not to say almost terminally confused, notion in
philosophy of mind and the one where things tend to go wrong at the
start. For example, the idea that we can appeal to some "inner"
nature of matter as in panpsychism, weaselling about "illusion" or
"seeming" in what is variously called materialism, physicalism or
naturalism, or the biological obscurantism resorted to by Searle in
the face of the Chinese Room argument. This is also part of what I
was getting at about unexamined extra presuppositions more or less
tacitly assumed in informal reasoning - in this case the implicitly
assumed "free lunch" of an inner or subjective point of view absent
any explicit supporting rationale. So one of the most interesting
things about comp for me has always been the possibility of
explicating such a perspective explicitly in terms of a logic
particular to the first-person.
Always trying to go right at the heart of the problem. OK.
The reason I see this as so central is to do with the gap between
syntax and semantics, to use Searle's terminology. This gap has
struck many as unbridgeable, whether frankly so as in mysterianism
(e.g. McGinn) or implicitly in the belief that all further
questioning will effectively be terminated by a completed
neuroscience.
So comp, here will go toward mysterianism. Comp gives a reason why
there is a mystery from our limited terrestrial and locally mechanical
points of view.
So what I find of particular interest in comp is the possibility of
bridging this gap in an intelligible manner.
OK.
But it is necessary a bit subtle. In a nutshell:
G cannot bridge the gap.
G* can bridge the gap (but G cannot believe in that bridge without
becoming inconsistent)
S4Grz (the first person) cannot see that there is a gap.
They have to dialog. The choice will be, like Paul Valery said,
between logic and war.
I cited Wittgenstein's idea of the explanatory ladder that is
discarded when the sought-after next level is reached. In this case
the ladder is the temporary conceptual aid of an external
interpretation (aka a view from nowhere) imposed on what is still
fundamentally a third-person syntactical procedure.
OK.
This is, or should be, a provisional "transcendence" from syntax to
semantics that is justifiable as an external prosthesis only so long
as it leads to a replacement that can do away with the need for it.
Hmm.... You seem to want to replace the Outer-God, by the Inner-God.
That is a risky move toward solipsim. S4Grz does not see the gap, but
it does not see the other minds either.
The needed replacement is an intelligibly internalised semantics, or
self-interpretation, which ISTM must be the very nub of a first-
personal logic.
OK. And as you know, that will be given, at the meta-level, by S4Grz.
But the machine cannot involves its own S4Grz box. From its machine's
view, it has simply no name. It is not genuinely Turing emulable. The
machine can discover it by *postulating* computationalism.
If this can be explicated in terms of a logic that is itself
emulable in computation, then - on the comp assumption that we
occupy the selfsame first-personal situation - the perceptual facts
of an inter-subjective concrete reality can then retroactively
illuminate the theoretical framework that has explicated them.
Through the bet in a sharable reality, but at the price of having to
justify its physical aspect without invoking a physical reality.
Equally, denying such facts becomes an effective nullification of
the sense of any framework paradoxically adduced in their support
(as in any Churchland or Dennett-style weaselling about "illusions").
We agree that such weaseling in the nth attempt by materialist to put
the first person under the rug.
I think these aspects may be so important to communicating these
ideas to a wider appreciation, as opposed to a technical/
professional audience, that if at all possible some Hilbert-style
man-in-the-street way of encapsulating their most essential
features, without involving a detailed point for point grasp of the
bulk of the technicalities, would be valuable indeed.
Most people use (often unconsciously) authoritative argument. So, they
will listen to the layman account when they are reassured by the
authority. They are unaware (unlike you) of the existence of the
problem to begin with. They confuse G and S4grz, the 3-p and the 1-p.
By the most essential features I mean for example the distinctions
between belief (or judgement) and perception, communicability and
incommunicability, formal and informal. No doubt you might point to
others. The UDA, while valuable in itself, assumes the first-person
position (as indeed it is entitled to do on the comp assumption) but
without providing any explicit rationale for it. Of course, that is
the intended function of AUDA and the machine interviews. But then
that takes us immediately into the complexities of the formidable
technical batteries of mathematical logic. Is it not possible that
there might be some intermediate pedagogical step?
To explain the formal, a minimum account of the formal is necessary. I
think.
You will not escape the (very easy) exercise I gave in my yesterday
post :)
Please don't panic.
If you can't do it, which is quite possible for diverse
(psychological) reasons, you will still understand, when I will
provide the solution, that it was extremely easy. And you will learn
something important, I think. Perhaps crucial.
And also you will see that we are very near the definition of the G
box, which I need to explain the Solovay's theorem, which is the main
reason why the machine point of view explodes in the 8 views. Without
Gödel's incompleteness theorem, everything I say would collapse in
triviality.
The KEY is that a consistent machine cannot proves its consistency,
but still can prove exactly: that if she is consistent she cannot
prove its consistency, a bit like a conscious being can grasp that it
cannot prove its consciousness to another.
Raymond Smullyan has made an account of G by replacing the "diagonal
lemma of Gödel" by his "island of Knight and Knaves" (in his book
"Forever Undecided"). It does not really work. The puzzle remains
technically difficult for most, and, worst, most people believe even
less in G, as it seems to require a fairy tale construct. Also, most
of his philosophical remark shows that he confused, like everybody, G
and S4Grz, once he refers to himself or to the mathematicians.
I tried to suggest to some people to read The Theaetetus of Plato as
an intermediate between UDA and AUDA. But here they tend to agree with
Socrates' refutation of Theaetetus, and again, I am forced to (try to)
explain to them that Gödel's incompleteness put some doubt on the
validity of Socrates definition (in the comp frame).
I will think about searching that intermediate account, between the
machinery and its intuitive meaning, meanwhile you might to try to
progress in my yesterday post, taking all your time, and asking any
question if something looks unclear or need complimentary information.
Maybe read only the (long) last paragraph.
Possibly *you* will succeed in finding that intermediate account! That
would be wonderfully helpful, for me and the others.
Anyway, thanks for the interest. It is only by open dialogs that we
can grasp the difficulties and ease the search toward solutions.
Bruno
David
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