Re: The notion of semantics in Rosen's writings

[Tim Gwinn <***>]

Carlos,

I know Judith has already replied, but sometimes multiple replies are
helpful. :)

> The first problem I have is with the definition of
> 'encoding' and 'decoding'. Rosen defines in the book
> Life Itself encoding and decoding as the 'translation'
> between 'formalisms'. I understand this as the idea of
> translating well-formed formulas given in a formal
> language to well-formed formulas of another formal
> language. But, what is 'encoding' and 'decoding'
> between a formal language and a 'natural system'?


TG: 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. This is associated with the notion of prediction,
whereby we use results from a formal model to predict what some value of
some observable would be if we were to measure it.

So, for example, if we measure the current in a physical electrical circuit,
we are encoding that observable into a number, such as "10 amps". If we then
use our model of electrical circuits, we can say that "if we double the
resistance in the circuit, the current should be cut in half to 5 amps,
according to our model". This is decoding the formal results back to the
physical system - making a prediction about it based upon our model.

There are much more extensive descriptions of the modelling relation in the
earlier books "Anticipatory Systems" and "Fundamentals of Measurement".



> Also, is not very clear to me what qualifies as a
> 'natural system', since Rosen defines them as systems
> "in the ambience or external world".


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.


>  I can't
> understand Rosen's point very well, so I'd pleased to
> know in what exact sense" the entailment structure of
> the language itself can change by virtue of what the
> language is about" and if Rosen effectively is
> asserting this.


TG: His statement is: "...we leave open the possibility that the entailment
structure of the language itself can change by virtue of what the language
is about?that is, that it can depend on semantic as well as syntactic
features." That is, there is no a priori reason to exclude such
possibilities. One of the common themes in Rosen's thinking is to remove
unjustified a priori restrictions wherever they occur.


>  Are the logical constants of the
> formal language of a formal logic a candidate for
> "entailment structure"?


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


Regards,
Tim