Truth (Post in a newsgroup about artificial intelligence; 2010-07-19)

Truth
Posted in comp.ai.philosophy 2010-07-19
Thread: Truth (Was: Re: PROOF INFINITY DOES NOT EXIST!...

I don't think "exist" is a good word to use about truth. I prefer "subsist" as the technical term. But that's a side issue.

This sub-thread on truth is marred by an absence of definition. Exactly what do you mean by truth? What do Curt and the others mean?

All the examples used are statements, which should be a clue. That is, an implicit stance in all the arguments so far is that truth is a property of statements. I don't think that is a good enough concept, as part two of this screed will I hope demonstrate.

A) Formal (logical) and contingent truth

I taught formal logic in high school, (I sneaked it in under the aim of "teach critical thinking".) As you might expect, some students twigged to the fact that "truth" is a vague, ambiguous, polysemous, slippery term.

"Logical truth" is clearly defined: A statement is "logically true" when it has the form X = Y, where X and Y are well-formed statements in some language, and the rules of inference allow the transformation of X into Y, and vice versa. Note that this is a characterisation of a statement.

However, it is not clear that X or Y are themselves true. A logical argument can demonstrate that some conclusion follows from some premises. If the premises are true, then so is the conclusion. But logic cannot demonstrate that the premises are true. You can show that the premises follow from some other premises, and so on, until you get to the axioms. But the truth of the axioms must be assumed. IOW, we need some means for agreeing on the truth of the premises.

At this point in the discussion, students started invoking experience, common sense, obviousness, etc. And realised that "what is true for one person is not true for another." It was difficult to get them past that, but in the end most accepted that some replicable procedure could guarantee a limited truth: if we have the same experience, and say the same things about it, then the odds are that what we say is true, more or less. If we differ, then what we both have said is more or less wrong. Since someone can always disagree about what we have said, all statements about common experience are more or less wrong (and conversely more or less true). This too is a characterisation of statements: here we have contingent truth.

B) Truth as a relationship

So, what do we mean when conceive "truth" as a property of statements? A statement is an image of a concept. It has the same relationship to a concept as a photograph has to its subject. Of both we say that they are "true" if we apperceive some similarity between the statement and the concept, the photograph and its subject. Ditto for a theory (model) and the slice of universe it refers to.

IOW, "truth" is a relationship between image and object, where "image" can be a sentence, a picture, a piece of music, an equation, etc, and "object" is whatever those images "are about".

That relationship between image and object is an unanalysed given: we either get it or we don't. It rests on some formal equivalences, on patterns. We are a pattern-perceiving species, so much so that we perceive patterns "that aren't really there", in the sense that a slightly different point of view may destroy the pattern, while a "real" pattern can be perceived from several (sometimes drastically different) points of view. (Science has been characterised as the search for patterns that remain the same no matter how you look at them.)

In a sense, we are democratic about truth, as Curt seems to be claiming: if a lot of people can see the same pattern from many different points of view, and/or if many people can replicate the pattern by some agreed-upon process, it is "really there." But we are also elitist: some patterns can be perceived only after more or less arduous training. But amongst those who have undergone this training, there is a pretty strong consensus on what the "real" patterns are, hence on what can be truthfully said about them.

It should be obvious that "consensus" truths are contingent. They are also empirical: some unanticipated future experience may change our notion of what they refer to, of their limits as true statements. This is so even in the realm of formal truths, where we often do not know a priori whether any two statements are logically equivalent, or whether some set of premises implies some set of conclusions. Only the experiment of devising proofs can decide the question. And those proofs may show that the equivalence or conclusion is limited to a range of values (ie, objects that it refers to). In this respect, mathematics resembles empirical science.

For more on how we arrive at some consensus about what's true, see Bas van Fraassen's "The Empirical Stance", Yale University Press, 2002.

Disclosure: Bas and I were classmates many years ago, and discussed much of what I've distilled above. He discusses these themes much more expertly than I can. Hence my recommendation of his book. We do not entirely agree: ask two philosophers a question, and you'll get four answers. At least. ;-)

Roger Cook and Karl Zimmerman. Magnetic North: Canadian Steam in Twilight (1999)

     Roger Cook and Karl Zimmerman. Magnetic North: Canadian Steam in Twilight (1999) In 1954 and ‘55, the authors, then teenagers, travelled from New York to Montreal and Canada to observe and photograph Canadian steam locos. Their account of their travels and their encounters with Canadian steam is evocative and personal. The photos are very good; and they were able to persuade Jim Shaughnessy, Don Wood and others to contribute photos to complement their story and illustrate the long ending of the steam era in Canada. Marie gave me this book for Christmas. It’s published by Boston Mills Press, and exhibits their usual very high standard of bookmaking, no typos, good looking page layouts, and superb photo reproduction. It's unlikely that teenaged railfans would be allowed to go on a similar quest these days. *** (2005)

Two books I didn't finish

     Kinky Friedman. When the Cat’s Away (1988) Friedman is one of those authors who thinks that obvious puns and wordplay are signs of wit and intelligence and will persuade the reader that plot, character, and narrative structure must be up to the same level. They aren’t. Or rather, they are, namely abysmally low. Didn’t finish this book, even though it was a present from RoRo, so I felt a little guilty tossing it.


     Graham Wright. Jog Rummage (1974) Billed as a fantasy in the same league as Tolkien’s work, this book is tedious in the extreme. The world Wright imagines never takes on the kind of compelling reality that a fantasy world must, else we lose interest. There are a few puzzles that I may regret never solving, such as why the world seems to be in darkness, illumined only by a Moon that occults at regular intervals, and the differences between the Rats and the Jogs, but I can live without that knowledge.

     (2005)

Four track planning books

     John Armstrong. 18 Tailor-made Track Plans (1983) I’m reading a number of track planning books. Why? Because I don’t to get down to actually building a layout, I suppose. Anyhow, these plans show how a different aspects govern or influence the plan. Lots of good ideas. Armstrong’s favourites, the double-sided backdrop and the empties in - loads out pairing of mine and power plant - show up on most plans. He also tries hard to make walk-in plans, and will accept an 18" aisle in order to achieve it. A couple of his plans could be cut up and rearranged to fit the 12'10" x 12'6" space I have available. Armstrong is always a pleasure to read. ***

     Mike Schafer ed. Railroads You Can Model (1976) A collection of good prototype information and rather strange track plans based on the railroads described. Armstrong would have done a better job. I don’t know who designed the plans. They are OK for operation, but waste space, using neither staging yards nor two-sided backdrops. The result is huge layouts, well beyond the capability of most people to build without assistance. The plans include interesting examples of how to adapt prototype track layouts to models, but otherwise this book has little value. That may be the reason it went out of print early on. *

     Linn Westcott. HO Railroad That Grows (2nd ed, 1972) The update consists partly of rewriting for clarity and concision, partly of redesign of the illustrations (including some new ones), and partly of updating the bench work and other technologies. The concept is still one of the best: write a book that follows what people actually do, namely set up a loop of track, then add to it. But show ways of changing and undoing earlier work so that the end result is a more interesting layout. I’m not sure how a novice would interpret this book. Would the bite-size projects reassure, or would the total of the work done intimidate? Anyhow, the book covers all the aspects of model railroading, and as such this book is as good as any other for introducing a neophyte to the hobby. **½

     Mike Schafer, ed. More Railroads You Can Model (1978) Better than the first book, since the plans assume a fixed space, and so show buildable layouts, whereas the first book showed assemblages of possible track plan elements. There’s also some use of two-sided backdrops and greater use of staging. The discussions of possible operations are more thorough. The Graham County RR is shown as a shelf layout with some care taken with the scenic design, the Milwaukee’s brewery branch is shown as both a shelf and a 4x8 two-deck switching pike, which would work quite well if structures were chosen to emphasise the cramped quarters of down-town railroading. But as with the first book, the real value lies more in the information about the prototype than in the track planning. Layout design has come a long way since these books were published. **½
      (2005)

Love sonnet

Love sonnet

You can’t write a love sonnet these days.
Regular rhythm & rhyme are out of fashion.
Let line and subject wander any way
they want.  You can’t limit passion
to fourteen lines.  So they say.
Now memories of your skin and hair distract
me. Your eyes, blue and grey, recall skies of fall weather,
bounded by winter’s cool and distant pact
that defines our endings. We don’t know whether
in our encounters we should yield or act.
But either way, we know we’ll be undone
by love’s illusion that we will still be one.

(2006 & 2013)

Death is Now My Neighbour (1997) TV episode

      Death is Now My Neighbour (1997, a Morse Special) A young woman is shot through a drawn blind, the murderer aiming at her silhouette. The only clue is a silly greeting card from a lover. The next morning, her neighbour, a journalist, is shot to death. Morse is in top form, and Lewis supplies the missing link when he realises that a pair of initials written down by the second victim indirectly point to the murderer. The motive for the killings derives from academic ambition: a new Master of Lonsdale College is about to be elected.
     A satisfying mix of blackmail, secrets, sex, abuse of power, and assorted minor sleaze. But if one hasn’t ever seen a Morse, one will be hard put to follow the allusive and elliptical style of narrative, which depends on the viewer’s familiarity with Oxford, Morse, Lewis and academia. The solution is plausible, and fairly solved. The acting hints at enough back story that we engage with each character, even the maid who brings the breakfast to the hotel guests. As usual, Dexter has an uncredited part, this time he says a Latin grace. A couple of bonbons: we discover Morse’s given name, and he meets a woman that’s his intellectual, aesthetic, and emotional equal. Fade-out on their arm-in-arm entry into a posh hotel.
     The episode feels like a series-ender, but there will be two more, and Lewis will apply the lessons learnt from Morse in his own career as Inspector. The series succeeds because of the consistency its fictional world, and because it pays attention to the effects of evil. We also like Morse, despite his flaws. Or because of them. Take your pick. This is the third of fourth time we’ve watched this episode. It wears very well. ***

W. A. D. Strickland. Chronicles of a Garden Railway (1968)

     W. A. D. Strickland. Chronicles of a Garden Railway (1968) Strickland is an engineer, and it show. He doesn’t tell us enough about some things, and too much about others. The organisation of the book is somewhat haphazard, too. However, the personal tone, the odd flashes of family history, and so on, make up for these formal faults, and the result is a charming chronicle, just as the title promises. As with many English books, the illustrations are either badly or not at all keyed to the text,  it’s as if the person responsible for the pictures hadn’t read the book. The technology of garden railways has much improved since Strickland built his 4mm scale, 16.5mm gauge layout, but I doubt that anyone today has had any more fun building and operating a garden railway. It’s quite clear that it was a family hobby. It helped that Strickland, like his wife, was an avid gardener. The information about suitable plants is worth the price of the book (15/- or 75p in 1971). ** (2005)