date:20170413

Re: Request to Bruno re modal logic

2017-04-13 Thread David Nyman

On 13 Apr 2017 2:56 p.m., "Bruno Marchal"  wrote:

On 13 Apr 2017, at 13:35, David Nyman wrote:

On 13 April 2017 at 10:09, Bruno Marchal  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.

O
K
, I've been re-reading the relevant section of
T
he Amoeba's Secret just to check my intuition about
what I said above
. There you remind us that in the final analysis the truth of p as distinct
from its believability can't be proved in the language of the machine.
Hence
we
 postulate
 it
as true by assertion. Let us accept this
 postulation
for the moment 
as "provisionally" true. Then let us consider the case where
 a
machine
"
believes
"
in the existence of

a concrete perceptual reality, the 1-truth of which it also
3-
asserts, but of course cannot communicate.
Concealed i
n
the
 gap between the provability and communicability of the
3-
belief and the unprovability and incommunicability of the
1-
assertion is the
elusive 
transition from syntax to semantics. The latter we will conceive as an
additional 
"
interpretation
"
of the former, but - by assumption of computationalism -
any such
interpretation
 *must be

Re: What are atheists for?

2017-04-13 Thread Quentin Anciaux

After ten years of peepee talk, you should have left this list... nothing
interesting came from you and nothing will... when you're wrong, you simply
ignore it and go back in a loop.

On the other side, I'm still confuse after that much time of dumb talk,
Bruno still wants to try to argue with you, it's pointless.

If I had to bet between the mythical friend of Bruno and you having any
friends... I'd bet on the realness of Bruno's friend.

Please leave and don't come back.

2017-04-13 19:07 GMT+02:00 John Clark :

> On Thu, Apr 13, 2017 at 10:04 AM, Bruno Marchal  wrote:
>
> > 
>> I did just bet to a friend that your answer would contain the word
>> "peepee". I win!
>>
>
> And I bet the same mythical friend that every post of yours would either
> contain a peepee personal pronoun, accuse me of being religious, refer to
> some fossilized ancient Greek, or contain the phrase "you confuse". I win.
>  
>
>
>  John K Clark
>
>
>
>
>
>
>
>
> --
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>



-- 
All those moments will be lost in time, like tears in rain. (Roy
Batty/Rutger Hauer)

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Re: Request to Bruno re modal logic

2017-04-13 Thread David Nyman

On 12 April 2017 at 20:59, Bruno Marchal  wrote:

2 ^(2^9) * (3^2) * (5^17) * (7^2) * (11^21) *(13^2) * (17*17)   *   3 ^
> 


Oh, I see what you mean:

3 ^(2^17) * (3^0) * (5^21) * (7^0) * (11^17)

PS Are "(" and ")" meant to be the same?

David

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Re: What are atheists for?

2017-04-13 Thread John Clark

On Thu, Apr 13, 2017 at 10:04 AM, Bruno Marchal  wrote:

> 
> I did just bet to a friend that your answer would contain the word
> "peepee". I win!
>

And I bet the same mythical friend that every post of yours would either
contain a peepee personal pronoun, accuse me of being religious, refer to
some fossilized ancient Greek, or contain the phrase "you confuse". I win.

 John K Clark

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Re: Request to Bruno re modal logic

2017-04-13 Thread David Nyman

On 12 April 2017 at 20:59, Bruno Marchal  wrote:

>
> On 11 Apr 2017, at 18:21, David Nyman wrote:
>
> On 10 April 2017 at 18:32, Bruno Marchal  wrote:
>
>>
>> On 10 Apr 2017, at 12:58, David Nyman wrote:
>>
>> Over the years there have been many references to various modal logics
>> deployed in support of the comp theory, in particular for the analysis of
>> categorical distinctions between third-person and first-person logical
>> consequences. Trouble is, when Bruno refers to these logics in explanation
>> of his points, the presentation is so technical that I for one have never
>> been able to follow these technicalities sufficiently well for them to
>> become intuitively obvious. Hence I've had to come up with my own amateur
>> versions.
>>
>> As David Hilbert famously said "A mathematical theory is not to be
>> considered complete until you have made it so clear that you can explain it
>> to the first man whom you meet on the street.". I wonder whether it would
>> be possible, Bruno, for you to contrive some sort of "man in the street"
>> presentation of the key logics deployed in your arguments and why indeed
>> you regard them as so central. I suspect that this is closely related to
>> the process you describe as interviewing the machine.
>>
>>
>>
>> Propositional modal logic is classical propositional logic with one
>> symbol more, usually, written with a box "’[]". It denotes an unary
>> operation. This means that if A is some formula, like (p -> p), []A is also
>> a "grammatically correct formula", meaning that [](p -> p) is a formula.
>>
>> Originally, modal logic was conceived, like logic itself, by Aristotle,
>> although he did not use any special symbol, but he used the word
>> "necessary" and "possibly", and used it to make his famous "Aristotelian
>> square":
>>
>>
>> Necessary  --  not-necessary
>>
>>
>> necessary-not --  not-necessary-not
>>
>> Now, not-necessary-not is the same as possibly. It is not necessary that
>> man is not rational is the same as "it is possible that man is rational".
>> "Possibly" is the dual of necessary, and is usually abbreviated by the
>> symbol diamond "<>". By definition it is ~[]~. We could have used  <> as
>> primitive, and define [] by ~[]~, and write Arstotle's square in the
>> following way:
>>
>> Not-possibly-not -- possibly-not
>>
>> Not-possibly  possibly
>>
>> When the box [] and diamond <> are used to denote "necessity " and
>> "possibly" in some metaphysical, sense, we say that it is alethic modal
>> logic. Leibniz, much later, will provide a sort of semantic for it by
>> interpreting the necessity by "truth in all possible world", and the
>> possibility by "truth in at least one world". This can help to agree that
>> alethic modal logic, see as a theory (set of axioms), can admit as axioms
>> the following formula:
>>
>> []p ->  p  (if p is necessary, then it is true)
>> []p -> [][]p (if p is necessary then it is necessary that it is necessary)
>> <>p -> []<>p (if p is possible, then it is necessary that it is possible)
>>
>> Now a theory is not just a set of axioms. It is a set of axioms together
>> with inference or deduction rules. Most logic have the modus ponens rule,
>> from a proof of A and a proof of A -> B, you can deduce B.
>>
>> The so-called *normal* modal logic have the modus ponens rule and the
>> necessitation rule, which says that if you have a proof of A, you can
>> deduce []A. They have also (by definition of normal modal logic, the axiom
>> [](p -> q) -> ([]p -> []q). In Leibniz theory,/semantics, you can verify
>> that if (p -> q) is true in all words, and if p is true in all worlds, then
>> q is true in all worlds. OK?
>>
>
> OK
> 
>
>>
>> Different modal notion will have different axioms, and sometimes
>> different inference rules.
>>
>> Now, modal logic is used in the "machine interview" to simplify a lot the
>> situation. The real difficulty, which is more demanding in term of lengthy
>> formalities, is the provability logic. Gödel succeeded in translating "A is
>> provable", with A put for some arithmetical formula (like "s(0) = 0") in an
>> arithmetical formula. That is longer to explain, I will proceed later.
>>
>> Tell me if you are OK up to now. We might also need to revise a bit
>> "simple" classical propositional logic, and to illustrate the difference
>> between
>> - this theory proves A (for A some being a classical proposition formula,
>> like (p -> q))
>> - this model satisfies A.
>>
>
> OK so far.
> 
>
>>
>> The idea that we can explain things to the man in the street is a bit
>> inapt in this context, because the difficulty of logic is that it is
>> necessary to NOT understand the formula, and to see that they are
>> manipulated formally only.
>>
>
> Yes, I do see the difference. Important point.
> 
>
>> So logicians start from what the first man in the street already know,
>> and he makes it incomprehensible.
>>
>
>

Re: Request to Bruno re modal logic

2017-04-13 Thread Bruno Marchal



On 13 Apr 2017, at 14:11, David Nyman wrote:


On 12 April 2017 at 20:59, Bruno Marchal  wrote:

On 11 Apr 2017, at 18:21, David Nyman wrote:


On 10 April 2017 at 18:32, Bruno Marchal  wrote:

On 10 Apr 2017, at 12:58, David Nyman wrote:

Over the years there have been many references to various modal  
logics deployed in support of the comp theory, in particular for  
the analysis of categorical distinctions between third-person and  
first-person logical consequences. Trouble is, when Bruno refers  
to these logics in explanation of his points, the presentation is  
so technical that I for one have never been able to follow these  
technicalities sufficiently well for them to become intuitively  
obvious. Hence I've had to come up with my own amateur versions.


As David Hilbert famously said "A mathematical theory is not to be  
considered complete until you have made it so clear that you can  
explain it to the first man whom you meet on the street.". I  
wonder whether it would be possible, Bruno, for you to contrive  
some sort of "man in the street" presentation of the key logics  
deployed in your arguments and why indeed you regard them as so  
central. I suspect that this is closely related to the process you  
describe as interviewing the machine.



Propositional modal logic is classical propositional logic with one  
symbol more, usually, written with a box "’[]". It denotes an  
unary operation. This means that if A is some formula, like (p ->  
p), []A is also a "grammatically correct formula", meaning that [] 
(p -> p) is a formula.


Originally, modal logic was conceived, like logic itself, by  
Aristotle, although he did not use any special symbol, but he used  
the word "necessary" and "possibly", and used it to make his famous  
"Aristotelian square":



Necessary  --  not-necessary


necessary-not --  not-necessary-not

Now, not-necessary-not is the same as possibly. It is not necessary  
that man is not rational is the same as "it is possible that man is  
rational". "Possibly" is the dual of necessary, and is usually  
abbreviated by the symbol diamond "<>". By definition it is ~[]~.  
We could have used  <> as primitive, and define [] by ~[]~, and  
write Arstotle's square in the following way:


Not-possibly-not -- possibly-not

Not-possibly  possibly

When the box [] and diamond <> are used to denote "necessity " and  
"possibly" in some metaphysical, sense, we say that it is alethic  
modal logic. Leibniz, much later, will provide a sort of semantic  
for it by interpreting the necessity by "truth in all possible  
world", and the possibility by "truth in at least one world". This  
can help to agree that alethic modal logic, see as a theory (set of  
axioms), can admit as axioms the following formula:


[]p ->  p  (if p is necessary, then it is true)
[]p -> [][]p (if p is necessary then it is necessary that it is  
necessary)
<>p -> []<>p (if p is possible, then it is necessary that it is  
possible)


Now a theory is not just a set of axioms. It is a set of axioms  
together with inference or deduction rules. Most logic have the  
modus ponens rule, from a proof of A and a proof of A -> B, you can  
deduce B.


The so-called *normal* modal logic have the modus ponens rule and  
the necessitation rule, which says that if you have a proof of A,  
you can deduce []A. They have also (by definition of normal modal  
logic, the axiom [](p -> q) -> ([]p -> []q). In Leibniz theory,/ 
semantics, you can verify that if (p -> q) is true in all words,  
and if p is true in all worlds, then q is true in all worlds. OK?


OK


Different modal notion will have different axioms, and sometimes  
different inference rules.


Now, modal logic is used in the "machine interview" to simplify a  
lot the situation. The real difficulty, which is more demanding in  
term of lengthy formalities, is the provability logic. Gödel  
succeeded in translating "A is provable", with A put for some  
arithmetical formula (like "s(0) = 0") in an arithmetical formula.  
That is longer to explain, I will proceed later.


Tell me if you are OK up to now. We might also need to revise a bit  
"simple" classical propositional logic, and to illustrate the  
difference between
- this theory proves A (for A some being a classical proposition  
formula, like (p -> q))

- this model satisfies A.

OK so far.


The idea that we can explain things to the man in the street is a  
bit inapt in this context, because the difficulty of logic is that  
it is necessary to NOT understand the formula, and to see that they  
are manipulated formally only.


Yes, I do see the difference. Important point.

So logicians start from what the first man in the street already  
know, and he makes it incomprehensible.


Good, only the incomprehensible is worth our time and effort!


For example take the formula (p -> p). the man in the street will  
be

Re: Request to Bruno re modal logic

2017-04-13 Thread David Nyman

On 13 April 2017 at 14:56, Bruno Marchal  wrote:

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.

But that's just it. We cannot ever "see" the other minds, nor even our own
for that matter, however much we examine mechanism. But we can believe in
them, as we do in our own. Perhaps the least confusing conception of this
(following Hoyle's heuristic, which as you know I'm fond of) is to conceive
the soul as indeed a soles ipse, though one with innumerable
personifications, each profoundly amnesic with respect to the others. But
surely that must be true of any computational device capable of
compartmentalising one program's states from another's. Is this then the
Inner-God? Perhaps, in concrete or perceptual form. But surely the abstract
Outer-God is still evidenced in that maximally-compressed creative widget
you call the UD?

David

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Re: What are atheists for?

2017-04-13 Thread Bruno Marchal

On 13 Apr 2017, at 15:53, John Clark wrote:

On Thu, Apr 13, 2017 at 3:55 AM, Bruno Marchal   
wrote:

 >> you blundered at the kindergarten level.

> Prove it, and without blurring the 1p and 3p.

Peepee tends not to have sharp edges, it's intrinsically  
blurry, just like the personal pronouns used by Bruno Marchal.

I did just bet to a friend that your answer would contain the word  
"peepee". I win!

For the personal pronouns, either study my post of yesterday to David  
Nyman, which will explain how to handle the pronouns in the  
arithmetical context, and, besides, will also help you to understand  
that computations are executed in arithmetic. Or use the definitions  
on which we have already agree, and that you have recently agree by  
citing Everett (cf the Y = II).

Bruno

John K Clark 

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http://iridia.ulb.ac.be/~marchal/

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Re: Request to Bruno re modal logic

2017-04-13 Thread Bruno Marchal



On 13 Apr 2017, at 13:35, David Nyman wrote:



On 13 April 2017 at 10:09, Bruno Marchal  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

Re: What are atheists for?

2017-04-13 Thread John Clark

On Thu, Apr 13, 2017 at 3:55 AM, Bruno Marchal  wrote:


>> >> 
>> you blundered at the kindergarten
>>  level.
>>
>
> > 
> Prove it, and without blurring the 1p and 3p.
>

Peepee tends not to have sharp edges, it's intrinsically
blurry, just like the personal pronouns used by Bruno Marchal.

John K Clark 

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Re: Request to Bruno re modal logic

2017-04-13 Thread David Nyman

On 12 April 2017 at 20:59, Bruno Marchal  wrote:

>
> On 11 Apr 2017, at 18:21, David Nyman wrote:
>
> On 10 April 2017 at 18:32, Bruno Marchal  wrote:
>
>>
>> On 10 Apr 2017, at 12:58, David Nyman wrote:
>>
>> Over the years there have been many references to various modal logics
>> deployed in support of the comp theory, in particular for the analysis of
>> categorical distinctions between third-person and first-person logical
>> consequences. Trouble is, when Bruno refers to these logics in explanation
>> of his points, the presentation is so technical that I for one have never
>> been able to follow these technicalities sufficiently well for them to
>> become intuitively obvious. Hence I've had to come up with my own amateur
>> versions.
>>
>> As David Hilbert famously said "A mathematical theory is not to be
>> considered complete until you have made it so clear that you can explain it
>> to the first man whom you meet on the street.". I wonder whether it would
>> be possible, Bruno, for you to contrive some sort of "man in the street"
>> presentation of the key logics deployed in your arguments and why indeed
>> you regard them as so central. I suspect that this is closely related to
>> the process you describe as interviewing the machine.
>>
>>
>>
>> Propositional modal logic is classical propositional logic with one
>> symbol more, usually, written with a box "’[]". It denotes an unary
>> operation. This means that if A is some formula, like (p -> p), []A is also
>> a "grammatically correct formula", meaning that [](p -> p) is a formula.
>>
>> Originally, modal logic was conceived, like logic itself, by Aristotle,
>> although he did not use any special symbol, but he used the word
>> "necessary" and "possibly", and used it to make his famous "Aristotelian
>> square":
>>
>>
>> Necessary  --  not-necessary
>>
>>
>> necessary-not --  not-necessary-not
>>
>> Now, not-necessary-not is the same as possibly. It is not necessary that
>> man is not rational is the same as "it is possible that man is rational".
>> "Possibly" is the dual of necessary, and is usually abbreviated by the
>> symbol diamond "<>". By definition it is ~[]~. We could have used  <> as
>> primitive, and define [] by ~[]~, and write Arstotle's square in the
>> following way:
>>
>> Not-possibly-not -- possibly-not
>>
>> Not-possibly  possibly
>>
>> When the box [] and diamond <> are used to denote "necessity " and
>> "possibly" in some metaphysical, sense, we say that it is alethic modal
>> logic. Leibniz, much later, will provide a sort of semantic for it by
>> interpreting the necessity by "truth in all possible world", and the
>> possibility by "truth in at least one world". This can help to agree that
>> alethic modal logic, see as a theory (set of axioms), can admit as axioms
>> the following formula:
>>
>> []p ->  p  (if p is necessary, then it is true)
>> []p -> [][]p (if p is necessary then it is necessary that it is necessary)
>> <>p -> []<>p (if p is possible, then it is necessary that it is possible)
>>
>> Now a theory is not just a set of axioms. It is a set of axioms together
>> with inference or deduction rules. Most logic have the modus ponens rule,
>> from a proof of A and a proof of A -> B, you can deduce B.
>>
>> The so-called *normal* modal logic have the modus ponens rule and the
>> necessitation rule, which says that if you have a proof of A, you can
>> deduce []A. They have also (by definition of normal modal logic, the axiom
>> [](p -> q) -> ([]p -> []q). In Leibniz theory,/semantics, you can verify
>> that if (p -> q) is true in all words, and if p is true in all worlds, then
>> q is true in all worlds. OK?
>>
>
> OK
> 
>
>>
>> Different modal notion will have different axioms, and sometimes
>> different inference rules.
>>
>> Now, modal logic is used in the "machine interview" to simplify a lot the
>> situation. The real difficulty, which is more demanding in term of lengthy
>> formalities, is the provability logic. Gödel succeeded in translating "A is
>> provable", with A put for some arithmetical formula (like "s(0) = 0") in an
>> arithmetical formula. That is longer to explain, I will proceed later.
>>
>> Tell me if you are OK up to now. We might also need to revise a bit
>> "simple" classical propositional logic, and to illustrate the difference
>> between
>> - this theory proves A (for A some being a classical proposition formula,
>> like (p -> q))
>> - this model satisfies A.
>>
>
> OK so far.
> 
>
>>
>> The idea that we can explain things to the man in the street is a bit
>> inapt in this context, because the difficulty of logic is that it is
>> necessary to NOT understand the formula, and to see that they are
>> manipulated formally only.
>>
>
> Yes, I do see the difference. Important point.
> 
>
>> So logicians start from what the first man in the street already know,
>> and he makes it incomprehensible.
>>
>
>

Re: Request to Bruno re modal logic

2017-04-13 Thread David Nyman

On 13 April 2017 at 10:09, Bruno Marchal  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.

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 what I find of particular
interest in comp is the possibility of bridging this gap in an intelligible
manner. 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. 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.
The needed replacement is an intelligibly internalised semantics, or
self-interpretation, which ISTM must be the very nub of a first-personal
logic. 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. 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").

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. 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?

David

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Re: Request to Bruno re modal logic

2017-04-13 Thread Bruno Marchal



On 11 Apr 2017, at 18:21, David Nyman wrote:


On 10 April 2017 at 18:32, Bruno Marchal  wrote:

On 10 Apr 2017, at 12:58, David Nyman wrote:








Good, but I guess I was also asking for some sort of shortcut to  
the intuitive power of all this, because if the only route to this  
is more of the above (however interesting in itself) then the point  
will go on being lost not only on the majority in this forum (unless  
I'm very much mistaken) but a fortiori on any possible wider  
audience. Which would be a pity.


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.


Bruno







David


Bruno

PS I guess you have missed my early introduction to modal logic on  
this list, many years ago! No problem.








Thanks in advance.

David

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Re: What are atheists for?

2017-04-13 Thread Bruno Marchal



On 12 Apr 2017, at 18:12, John Clark wrote:

On Wed, Apr 12, 2017 at 10:43 AM, Bruno Marchal   
wrote:


> Step 3 is kindergarden level.

I agree, and yet you blundered at the kindergarten level.


Prove it, and without blurring the 1p and 3p.

Bruno





And that's why I stopped reading at step 3.

John K Clark

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Re: Request to Bruno re modal logic

Re: What are atheists for?

Re: Request to Bruno re modal logic

Re: What are atheists for?

Re: Request to Bruno re modal logic

Re: Request to Bruno re modal logic

Re: Request to Bruno re modal logic

Re: What are atheists for?

Re: Request to Bruno re modal logic

Re: What are atheists for?

Re: Request to Bruno re modal logic

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Re: Request to Bruno re modal logic

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