String of Signs

Worthwhile Comments

In Uncategorized on November 21, 2010 at 7:52 pm

I left some comments on Nick Rowe’s blog, concerning rational expectations and Paul Davidson’s critique, of the non-ergodic nature of economics.   Which I think is a more profound criticism of modeling,  however growing impatient for a response, I got into it with Greg Ransom, who was claiming that he could state 5 true things that could not necessarily be mathematically tractable.  And I think I get that,  Godel’s incompleteness theorem and what not. But  I countered with, my pet post-modern information theory hybrid, and he immediately pointed out a gap in my knowledge.   Wittgenstein.

quotes from the only book I have ready-to-hand, Stuart Russel, and Peter Norvig’s AI A Modern Approach.

  • “The world is everything that is the case.”
  • Truth tables as a method of testing the validity of unsatisfiability of sentences in the language of propositional logic were introduced independently by Wittgenstein 1922 and Emil Post 1921.
  • The difficulty of providing exact definitions for most natural categories was explained in depth by Wittgenstein (1953) in his book Philosophical Investigations.  He used the example of games to show that members of a category shared “family resemblances” rather than necessary and sufficient characteristics.
  • The idea of language as action stems from 20th century linguistically oriented philosophy. Witgentstein 1953.

Difficulty in providing exact definitions for most natural categories, seems to be close to the point I was trying to make.  But maybe that means there would only ever be one instance in each category, using strict formal constructs. So maybe while I think natural language is too loose, the counter-point being formal language is too tight.

But I believe fuzzy logic, and probabilistic reasoning, has the middle ground.

 

update.

I deleted a paragraph that needlessly criticized models.

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