Re: The notion of semantics in Rosen's writings

[Carlos Limarino <***>]

The 'encoding' and 'decoding' notions are very
confused to me in Rosen's writing. For example, Tim
Gwinn says "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." If
this definition is correct, Rosen is referring simply
to measurement, so 'encoding' is the use of an
instrument to measure something. Judith Rosen says,

>He begins with the relation between a natural system
and a model of it. Then he goes >on to say that we can
make models of models, too. Any model is a type of
>"formalism". So, if we have a model and we want to
create another model: another >way of studying the
entailment structure that the first model possesses...
then we must >go through the process of encoding that
entailment structure from the first model into >the
second model, and also the process of decoding by
making predictions, using the >new model's entailments
to predict what the original model's entailments would
>predict. An example of this would be to take a
statistical model and create a graph >from it. The
graph is only an accurate representation if the
information from the >statistical model is converted
accurately, from one form into the other form. All the
>entailment relations contained in the statistical
model must be transferred over. That's >encoding. See?

Sadly, I can't see anything clear in your passage.
Your definition of 'encoding' is clearly different
from Tim Gwinn's. What are 'entailment structures' and
how they're transferred? Even more, Rosen in the
mentioned essay in my previous post says:

"The crucial ingredients are the arrows 2 and 4, which
I call encoding and decoding, respectively. (I have
discussed the anomalous features of these arrows in
more
detail in Life Itself, section 3H.) They do not fit
entirely inside either the object system or the model;
they do not represent entailments, nor are they
themselves entailed. They manifest what Einstein (with
Infeld; 1938:33) once called ?free creations of the
human mind,? on which he believed science depends.
They introduce an obvious further semantic element
into the model, over and above what semantic (e.g.,
nonformalizable)
features may already be present in the model."

Does he believe that the act of measurement is a "free
creation of the human mind" and "introduce an obvious
further semantic element into the model, over and
above what semantic (e.g., nonformalizable) features
may already be present in the model"? Suppose I want
to calculate the translational kinetic energy of a
body, using the simple formula Et = 1/2m*v^2. Is Rosen
suggesting the measurement instrument I use in order
to determine the mass of a body introduce "an obvious
further semantic element"? 

Judith Rosen wrote:

>This is the standard modus operandi of theoretical
science, as a matter of fact. "If P is >true, then
that means Q must be true." In mathematics (which is
another language, >with its own implication structure,
different from English) it's written as an arrow  ( P
->--> Q ). Another way to look at it is; "Q depends on
the truth of P, therefore in order >for Q to be true,
P must be true."


>An example might be: "If we have a clear sky tonight,
we'll be able to see the Perseid >meteor shower"
(which is still continuing, by the way). So, P =
"clear sky tonight" and >Q = "see the Perseid meteor
shower". If P is not true, then Q will not be true,
either: if >the sky is not clear, we will not be able
to see the stars.
 
>This goes in the other direction, too. If someone
says; "I was watching the shooting >stars last night--
it was AMAZING!" You know that the sky had to be
clear.

I don't understand very well what Robert Rosen and you
are saying by "If P is true, then that means Q must be
true." 

"If we have a clear sky tonight, we'll be able to see
the Perseid meteor shower"

If this is a material implication, is simply false
that if "we have a clear sky tonight" is false "we'll
be able to see the Perseid meteor show" is also false.
You're confusing the truth value of "p" and "q" with
the truth value of "p->q".

>The fact that we can give examples of this kind of
entailment structure (If P, then Q) in >both English
and in mathematics actually constitutes a proof of
both the statement >above, and also an example of a
modeling relation. 
 
>As a proof that the truth values come outside the
syntax, itself: entailment is the basis >of all
causality. That's something that is true outside of
all human languages. In a >sense, entailment is P and
causality is Q. The fact that entailment patterns
hold, >regardless of the venue is the only reason we
can "do science" at all, because this fact >is what
allows us to make models that actually can predict the
future behavior of the >system being modeled.

What is the definition of 'entailment' in Rosennean
thinking (as I suppose you use his definition)? I
don't understand what "entailment is the basis of all
causality" could mean. If the given example
constitutes a 'modelling relation', where is the
'encoding' and the 'decoding' in "If we have a clear
sky tonight, we'll be able to see the Perseid meteor
shower"? Are you suggesting the material implication
'encodes' the causal trajectory of a meteor? As you
said:

>So, assuming that the system we want to model is a
natural system, the entailment >structure of the
system is called "causal entailment" and the
entailment structure of the >model is called
"inferential entailment". So, in our "If P, then Q"
scenario... that can be >a model if the entailments
are accurately transferred from the natural system we
want >to model. 
 
(1)     "Dental caries causes cavities"
(2)     "If Bob is competent, then Bob should get the
job."

Is (1) a 'casual entailment' and (2) an 'inferential
entailment'? 

Judith Rosen wrote:

>Natural systems, in his parlance, are "actual, real
systems" as opposed to models or >simulations. They
can be systems made by humans (like a house) or
systems which >spontaneously self-organize (like a
hurricane). But he takes pains to point out that this
>is a very subjective activity: he says that science
always is a subjective activity. >Objectivity is a
myth, at least the way we define it in science. Worse;
the more we try >to achieve it, the less likely we are
to actually succeed. In any case, his use of the word
>"natural" in this sense refers to "real".

Tim Gwinn wrote:

>TG:  A natural system is simply a collection of
observables from the 
>World outside of us. A 'car' or a 'cat' or a 'proton'
is a natural system,
>comprised of the observables we have chosen to
consider as belonging to 
>that system. Again, the books AS and FM go into much
more detail.

A computer running a simulation is not a natural
system? If the definition is "very subjective", a rock
perfectly could be a 'natural system'. What are the
'causal entailments' of a rock? 

Judith Rosen wrote:

>I would say yes, if by "logical constants" you are
talking about the rules of the formal >language.

Tim Gwinn wrote:

>TG: 'Entailment structure' refers to relationships
between entities, 
>not to
>entities themselves. Can you give an example of what
you mean?

I'm using the traditional definition of logical
constant or operators or connectives like not, or,
and, implication, biconditional (replace by the
correspondent signs). 

Judith Rosen says:

>But most internal rules have referents to external
"things". Even simple systems, like a >car, carry
semantic entailment information that isn't
syntactical. For instance, cars have >tires.

But Rosen says: 

"We shall not make this supposition
in advance; we leave open the possibility that the
entailment structure of the language itself can change
by virtue of what the language is about"

And as I understand he defines the 'entailment
structure' of a 'formalism' as 'inferential
entailment'. Is not clear to me what could change that
'inferential entailment' if logical constants are part
of it.

__________________________________________________
Correo Yahoo!
Espacio para todos tus mensajes, antivirus y antispam ¡gratis! 
¡Abrí tu cuenta ya! - http://correo.yahoo.com.ar