Paradigms, Playgrounds, Programmes, Programs

Re: R.J. Lipton and K.W. ReganMounting Or Solving Open Problems

Comment 1

Sometimes the programme must simply be to keep developing our understanding of the ground on which the mountains rest.

Comment 2

It might be observed that the concept of a research programme is closely related to the concept of a research paradigm, about which much has been written.

Comment 3

As long as we’re brainstorming in a laid back sort of way …

Folks who find propositional logic — and the whole space between zeroth order logic and first order logic — more of a fascinating playground for exploration than a dog run for the questying beast might find it fun to look at the graph-theoretic calculi for propositions and boolean functions that derive from C.S. Peirce’s logical graphs.  There is an extension of Peirce’s tree-form graphs to cactus graphs that presents many interesting possibilities for efficient expression and inference.  And the resulting cactus calculus facilitates the development of differential logic, extending propositional calculus analogous to the way differential calculus extends analytic geometry.

Comment 4

The following primer on differential logic uses the cactus graph syntax to represent propositions (boolean functions $latex f : \mathbb{B}^k \to \mathbb{B}) and the operators on propositions that arise in developing the subject of differential propositional calculus.

The cactus graph syntax for propositional calculus is based on minimal negation operators.

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Triadic Relations, Intentions, Fuzzy Subsets • Discussion 3

Re: Peirce List DiscussionGary MooreStefan Berwing

I intend to get back to this subject as soon as possible but the dire political situation in my home state is once again eating up a lot of my time and energy, so I’ll just post a link to what I wanted to discuss next, namely the classical sense of probability from which the modern mathematical formalization evolved, a sense expressed in words like likelihood and likely story and thus bound up with the concepts of analogues, copies, exemplars, icons, images, likenesses, metaphors, models, morphisms, paradigms, similes, simulations, and a host of similar notions.

Resources

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Triadic Relations, Intentions, Fuzzy Subsets • Discussion 2

Re: Peirce List DiscussionStefan Berwing

Let us put fuzzy sets to one side for the moment and take up the matter of belief you raised, as I believe that connection is very apt.

As it happens, there was a moment in the history of philosophy when a thinker of note was driven almost to the point of despair in his trials to analyze situations of belief by means of cobbled together dyadic relations, and I truly believe that had he persisted just a little while longer he might’ve broken through the mental blockade of hidebound habits to try triadic relations instead.  But it would not be, partly because he was discouraged in his efforts by the criticism of another thinker of note whose opinion, I believe, he may have trusted too much.

At any rate, let us enter the fray in medias res at the point where Bertrand Russell asks the following question:

How shall we describe the logical form of a belief?

I want to try to get an account of the way that a belief is made up.  That is not an easy question at all.  You cannot make what I should call a map-in-space of a belief.  You can make a map of an atomic fact but not of a belief, for the simple reason that space-relations always are of the atomic sort or complications of the atomic sort.  I will try to illustrate what I mean.

The point is in connexion with there being two verbs in the judgment and with the fact that both verbs have got to occur as verbs, because if a thing is a verb it cannot occur otherwise than as a verb.

Suppose I take ‘A believes that B loves C’.  ‘Othello believes that Desdemona loves Cassio’.  There you have a false belief.  You have this odd state of affairs that the verb ‘loves’ occurs in that proposition and seems to occur as relating Desdemona to Cassio whereas in fact it does not do so, but yet it does occur as a verb, it does occur in the sort of way that a verb should do.

I mean that when A believes that B loves C, you have to have a verb in the place where ‘loves’ occurs.  You cannot put a substantive in its place.  Therefore it is clear that the subordinate verb (i.e. the verb other than believing) is functioning as a verb, and seems to be relating two terms, but as a matter of fact does not when a judgment happens to be false.  That is what constitutes the puzzle about the nature of belief.

You will notice that whenever one gets to really close quarters with the theory of error one has the puzzle of how to deal with error without assuming the existence of the non-existent.

I mean that every theory of error sooner or later wrecks itself by assuming the existence of the non-existent.  As when I say ‘Desdemona loves Cassio’, it seems as if you have a non-existent love between Desdemona and Cassio, but that is just as wrong as a non-existent unicorn.  So you have to explain the whole theory of judgment in some other way.

I come now to this question of a map.  Suppose you try such a map as this:

                                 
             Othello             
                |                
                |                
             believes            
                |                
                v                
 Desdemona -----------> Cassio   
              loves              
                                 

This question of making a map is not so strange as you might suppose because it is part of the whole theory of symbolism.  It is important to realize where and how a symbolism of that sort would be wrong:

Where and how it is wrong is that in the symbol you have this relationship relating these two things and in the fact it doesn’t really relate them.  You cannot get in space any occurrence which is logically of the same form as belief.

When I say ‘logically of the same form’ I mean that one can be obtained from the other by replacing the constituents of the one by the new terms.

If I say ‘Desdemona loves Cassio’ that is of the same form as ‘A is to the right of B’.

Those are of the same form, and I say that nothing that occurs in space is of the same form as belief.

I have got on here to a new sort of thing, a new beast for our zoo, not another member of our former species but a new species.

The discovery of this fact is due to Mr. Wittgenstein.

(Russell, POLA, pp. 89–91).

And just by way of picking up the res into the middle of which we’ve jumped:

Reference

  • Bertrand Russell, “The Philosophy of Logical Atomism”, pp. 35–155 in The Philosophy of Logical Atomism, edited with an introduction by David Pears, Open Court, La Salle, IL, 1985.  First published 1918.
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Triadic Relations, Intentions, Fuzzy Subsets : 3

There is at present an extensive literature on fuzzy sets and fuzzy logic.  I got another brush with the world of fuzzy in the 1990s when I returned to grad school in a systems engineering program, partly because my adviser was interested in applications to decision support and optimal control and that intersected with my work on Inquiry Driven Systems (1) (2).

For reasons I have explained before and will try to explain again later on, I am not especially concerned with the variety of fuzzy, modal, and multi-valued logical systems covered in the literature, but only with the threshold of generalization where we find ourselves drawn from dyadic relations to triadic relations as models for dealing with complex phenomena.  Still, I think it’s worth having a look at fuzzy set theory in order to develop ideas about the general thrust of generalization from 2-adic to 3-adic.

Here’s a brief article from PlanetMath that gives a minimal introduction to fuzzy set theory.

The article uses different letters for things than I am using, so I’ll transcribe what I need from it in the next installment.

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Triadic Relations, Intentions, Fuzzy Subsets : 2

We imagine all the things we might want to talk about in a given discussion as collected together in a set X called a universe of discourse.  (In probabilistic or statistical work it might be called a sample space.)

By way of shorthand notation, let us single out two domains of values, the boolean domain ℬ = {0, 1} and the unit interval ℐ = [0, 1].

In many applications, especially computational or statistical ones, it is often useful to represent any given subset S of X by means of a function from X to ℬ known as the characteristic function or indicator function of S in X.

By way of notation, we write fS : X → ℬ for the indicator function of S in X, and define it as follows:

fS(x) = 1   if and only if   x is an element of S.

All that is standard notions from ordinary set theory.

Fuzzy sets, more properly, fuzzy subsets of a given set X will be defined in a way that generalizes the target values in the previous definition from the boolean values in ℬ to the real values in ℐ.

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Triadic Relations, Intentions, Fuzzy Subsets • Discussion 1

Re: Peirce List DiscussionStefan Berwing

Frequencies, histograms, and probabilities are one way to think about degrees of membership in a fuzzy subset, but there are cautions to be observed in doing that.

Consider the following triadic relations:

  • xr S   =   x is in S to the degree r
  • xj S   =   x is in S to the judge j

And consider their intensional counterparts:

  • x isr P   =   x is P to the degree r
  • x isj P   =   x is P to the judge j

These relations are all defined abstractly enough that you could probably fit them out with almost any reasonable statistical model.

One adds concreteness to these abstractions by specifying how the triadic relations combine under operations analogous to the usual set-theoretic and logical operations.  It’s been a while since I studied it but I seem to recall that most of the fuzzy literature works with rules for combining degrees that cannot be interpreted as probabilities, rather as what they like to call possibilities.

How one combines interpreters is a really good question.  This may be another one of those places where we have to turn Peirce’s trick of replacing interpreters with interpretants.

Posted in C.S. Peirce, Fuzzy Logic, Fuzzy Sets, Intentional Contexts, Intentional Objects, Intentionality, Intentions, Logic, Logic of Relatives, Lotfi Zadeh, Mathematics, Peirce, Relation Theory, Semiotics, Triadic Relations | Tagged , , , , , , , , , , , , , , | 1 Comment

Triadic Relations, Intentions, Fuzzy Subsets • 1

Re: Foundations Of Math DiscussionLotfi Zadeh

Way back during my first foundational crisis (1967–1972), I had been willing to consider almost any alternatives to the usual set theories, so I can remember looking at early accounts of fuzzy set theory.  There was in addition a link to certain issues that came up in my studies of C.S. Peirce, especially the idea that many dyadic relations we use in logic, mathematics, and semantics — as a rule being functions that assign meanings and values to symbols and expressions — are better understood if taken in the context of triadic relations that serve to complete and generalize them.

My line of thought went a bit like this:

Consider a fuzzy set as a triadic relation of the form x ∈r S among an element x, a degree of membership r, and a set S.

Ask yourself:  Where do these assigned degrees of membership come from?  Imagine that they come from averaging the results of many judges making binary {0, 1} = {Out, In} = {∉, ∈} decisions.

Now consider the more fundamental triadic relation from which this data is derived, the relation of the form x ∈j S that exists among an element x, an interpreter (judge, observer, user) j, and a set S.

That formulates fuzzy sets in a way that links up with many Peircean themes.

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“Is it possible to advance philosophy today?”

Re: Stephen Rose

Is it possible to advance philosophy today?  To do so, one would have to use terms that appear to have evolved in different disciplines to a point where dialog is almost impossible, even when desired.

I suppose that would depend on one’s definition of philosophy, one’s definition of advance, and one’s definition of possible.  Now there’s a fearsome threesome if ever I saw one!

I believe it is possible to advance the state of logic, mathematics, and science, not just in theory but also in practice.  And Peirce’s hints, ideas, and methods open up so many directions of exploration that I constantly wonder at the fact that all of them remain barely touched even today.  If part of philosophy’s task is to bring about critical reflection on the state of logic, mathematics, and science, among other things, then I can’t help but to charge it with falling down on the job for failing to nudge these other arts further along.

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Abduction, Deduction, Induction, Analogy, Inquiry • 2

Re: Peirce ListKirsti Määttänen

Inference from particulars to particulars is also called analogy.

Peirce gave a fair account of the logic behind statistical inference, as used in the research sciences from before his time to the present day.  That logic depends on a fair amount of probability theory, which Boole had already begun to cast as a generalization of classical logic, but a lot of the underlying logic of inquiry is already visible in the infrastructure at the level of propositional and predicate logic.  And that much of the basic structure was more or less roughly outlined by Aristotle himself.

Here’s a set of notes on the role of abduction, deduction, induction, and analogy in inquiry, as seen in the works of Aristotle and Peirce.

More discussion of these topics can be found on the following pages.

cc: Peirce List (1) (2) (3) (4) (5) (6)

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That Aristotling Town

The man’s reputation for dualing exceeds him.
It’s a mode more the eyebeam of the beholden.
Western wayfarers will claim him their founder,
But they founder on the way his meta*physick
Straddles the narrow straits of their harbor.

Jon Awbrey
30 Oct 2012

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