Waclaw Kusnierczyk schrieb:
> Yes. I think John has conflated a theory's being true and a theory's
> being empirically adequate. (01)
I doubt this very much. He has at least not given me this impression. He
is a fallibilist who often refers to Peirce. Being a fallibilist means
to accept that a theory may be empiricially adequate for a time without
being completely true. I think what (reading vQ:s mail) might be
pedagogically missing in Peirce and Sowa is a concept advertised by
another fallibilist, Karl Popper. He verbalizes it using three different
expressions: ‘truthlikeness’, ‘verisimilitude’, and ‘approximation to
truth’. Theories are not just either true or false; truth can take
degrees. And very very much tells in favor of the view that most
empirically adequate theories have a rather high degree of truthlikeness. (02)
> a theory may perfectly fit the data and
> allow for usable predictions, even if it is wrong about the nature of
> the phenomena addressed.
> I thus support the statement that there *is* a difference between a
> theory's being correct and its being accurate, and consequentially, that
> there is a difference (beyond the obvious syntactic one) between saying
> that a theory is true and that a theory is accurate.
> If you could prove that a theory necessarily makes correct predictions
> in every possible case, you could claim that the theory is true (but I
> am not still convinced this would be correct). You can't (not in
> empirical sciences, perhaps in mathematics); theories are induced or
> abduced from partial data (data about only some part of the reality).
> They are not tested on every conceivable input, since what is the set of
> all conceivable inputs is only another theory.
>> By the same token, if someone offers a theory that does not give correct
>> predictions or that relies upon what I suspect are fanciful premises,
>> i.e., airplanes fly because the motors attract fairies that carry the
>> plane aloft, I can ignore that theory because it is less useful than
>> some other theory. Such as calculating the thrust needed by a jet engine
>> to propel the next generation of jet aircraft. I don't ever have to
>> reach the issue of "truth" but can rely upon theories that I find useful
>> for some particular task.
>>> Newtonian mechanics, in fact, is such a theory. During the past
>>> century, physicists have discovered phenomena of relativity and
>>> quantum mechanics, for which Newtonian mechanics makes incorrect
>>> predictions. However, for macroscopic phenomena at nonrelativistic
>>> speeds (i.e., for cars and airplanes) Newtonian mechanics is a true
>>> description of reality. I trust my life to Newtonian mechanics
>>> whenever I drive a car or fly in a plane.
>>>> A friend of mine sent me the following example:
>>>> There is an elementary model in electrical engineering, called
>>>> the "4-terminal network". The thing is a closed ebony container,
>>>> with an input, an input return, an output, and an output return.
>>>> The student is given a set of inputs and outputs, and asked to make
>>>> the simplest thing that he can which could be substituted for the
>>>> actual contents of the container. The problem of what is _actually_
>>>> inside the container is dismissed as impossible.
>>> That is an excellent example.
>>> If anyone defines a theory (i.e., a set of axioms) that correctly
>>> predict the output for every conceivable input, then I would say
>>> that the theory is a true description of the behavior of that box.
>> First, "every conceivable input" isn't really possible. Testing is
>> always with a finite set of inputs.
>> Second, I would say that a theory (set of axioms) that correctly
>> predicts all the inputs we have tried is simply accurate. That is it
>> agrees with the inputs and predicted outputs.
>> Calling a theory "true" or "part of truth" doesn't make it any more or
>> less accurate. The aether theory was at one time thought to be "true"
>> but that did not save it from being superceded.
>> I suppose that is what I am missing. What claim is it, beyond accuracy
>> (agreement of theory with observations), that you want to make by saying
>> something is "part of the truth?" (If any claim at all. I may simply be
>> over-reading your statement to imply more than it is actually saying.)
>> Hope you are having a great day!
IFOMIS, Saarland University
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