Re: The notion of semantics in Rosen's writings

[Carlos Limarino <***>]

Tim Gwinn wrote:

> No, no. Again, encodings and decodings are the
> *mappings*. What he is saying is that choosing how a
physical observable
> will *map* to a formal model (and thus also, the
inverse mapping back to
> the natural system), is our free choice.

But you also wrote earlier:

> Encoding is the mapping of a phenomenon (i.e.,an
observable) in the
> natural system to a counterpart in the formal
system.This is associated with
> the notion of measurement, where measuring some
physical observable results
> (typically) in a number, a formal thing.Decoding is
the inverse operation, mapping a >formal entity to an
observable in the natural system.

If you call a number a 'formal entity', the idea of
encoding is 'mapping a formal entity in the natural
system' and viceversa. So, what is the difference
between 'encoding' and just measurement? It is not
very clear to me.  You wrote "What he is saying that
choosing how a physical observable will *map* to a
formal model, is our free choice", but Rosen says in
"Syntatics and Semantics in Languages" that
'encodings' and 'decodings' manifest a 'free creation
of the mind' (see my earlier message). In conclusion,
"encodings is the *mapping*" is: a) Mapping a number
to an observable entity in the natural system, b) the
result of the usual, well-known activity of
measurement in science or c) Choosing how a physical
observable will *map* to a model. I need enlightening
about this Rosennean notion. 

Tim Gwinn wrote: 

> 'Entailment structures' refer to the organization of
entailments in 
> a system. In a formal system, entailments are the
inferential relations; 
> in a natural system, entailments are the causal
relations in a system. The
> entailment structures are *mapped* across the
modeling relation.

I'm afraid I find the notion of 'entailment' very
confusing in Rosen's writings. If you define the
'entailments' of a formal system as inferences and the
'entailments' of a natural system as causal relations,
it would be very illustrative to me understand it by
example: what are the 'encodings', 'mappings' and
'entailment structures' between and in Et=1/2m*v^2 and
a rock if I want to calculate translational kinetic
energy of it?

Tim Gwinn wrote:

>TG: A physical computer? Of course it is would be a
natural system. 
>Where did I say it wasn't?

That was a question for Judith Rosen.

>This depends on how you define the system. If you
define the system 
>as a single, solid, inelastic entity, then there are
very few >observables to this
>system, and it has little or no causal entailment
structures.
> If you define 
> the rock to include its sub-atomic interactions, its
thermal 
> properties, etc., then there is alot of causal
interactions going on > within the system. *How* you
define the system is subjective in this > sense. The
point is that there is no absolute "right" way to
define > a given system. 

But it seems to me that if you're right, Rosen's
notions of 'encoding' and 'decoding' are redundant if
definition (c) is right: For what reason would we need
to find a "congruence between inferential entailment
and causal entailment" if 'causal entailment' depends
in our definition of a system?

>Ah, logical *connectives*. Ok, now I see. Your
original question 
>was:
>"Are the logical constants [connectives]of the formal
language of a 
>formal
>logic a candidate for "entailment structure"?"  Yes,
logical 
>"implication"
>is in fact just another name for "inferential
entailment" (See LI p. 
>46).

So, is Rosen suggesting that given the semantics of
proposotional logic, the logical constants change if
the propositions have a different truth value? (See my
first message). 


        


        
                
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