Re: Summer night dreams: advice & opinions wanted! -Reply
Vern R. Walker (lawvrw@OFFICE.HOFSTRA.EDU)
Wed, 12 Aug 1998 00:49:06 -0400
At the risk of snapping a worn thread, I am prompted by Peter*s honest plea and by the subsequent exchange to make a few brief observations.
First, I agree that, with regard to many propositions, the act of asserting is warranted by (and perhaps only by) also asserting certain causal statements to be true or probably true. For example, my assertion that the sun will indeed *rise* once again tomorrow is warranted by my theory of astronomical physics. Such causal statements may or may not support observably testable frequency statements. It is also true, but only marginally relevant, that asserting warranted propositions is itself a result of cause-and-effect, as is any activity that occurs in space and time.
But inferential activity (that is, asserting warranted conclusions) does not ALWAYS proceed by positing a causal explanation. A mundane but classic example is the case of warrant by appeal to linguistic meanings. *An unmarried neighbor is a bachelor* is an example. My warrant for asserting it to be true rests in part on the meaning of *unmarried* and *bachelor.*
On the other hand, there are examples of propositions whose warrant is less straightforward, and which appear to be hybrids or perhaps of some other kind altogether * such as *2 is less than 3,* *human beings die,* and *F = MA.* I prefer to be agnostic on how many types of warrant we COULD usefully distinguish -- this depends, after all, upon devising a successful taxonomy of warrant, which depends in turn upon our objectives in engaging in such taxonomizing. So, without a context to provide objectives and criteria of success, I am not inclined to sign on to Peter*s nomenclature of *propositions about facts,* *ancillary hypotheses,* and *ancillary evidence.* Nor on to any other abstract formalism. It all depends upon what you*re up to.
My minimal point here is that it is generally useful to treat inferring conclusions and providing causal explanations as conceptually distinct activities, and these activities should not be confused or needlessly conflated.
Second, Peter*s list of *distinct possibilities explaining why, e.g., s is uncertain given r* (7/29/98) is intriguing for its omissions. I would have thought that the paradigmatic reason why *s is uncertain given r* is that we cannot DEDUCE s from r. This is not a circular or uninteresting account. We have invented in Western logic a reasonably well-defined test of *necessarily implies* or *is deducible from,* and this test now functions as the meaning of *necessary inference.* To be (merely) probable is to be not deducible.
A psychological analog of deducibility is imaginability. If I can imagine a world in which r is true but s is not, then this also warrants my asserting *s is uncertain given r.*
The linguistic analog is meaning. If I assert that I can imagine a married bachelor, then it must be that I have misunderstood the meaning of either *unmarried* or *bachelor* (or perhaps the word *imagine*).
But the success of this paradigm of certainty or necessity, and its extreme usefulness, derives from the conceptual alignment of deducibility and imaginability and meaning. These three together provide the opportunity for understanding uncertainty. Historically, our quantitative work on probability as an operational account of uncertainty is parasitic on our conceptions of necessity, imagination, and meaning.
Third, and finally, propositions cannot exhaust meaning, nor are they ever more than pieces to be moved in a highly evolved linguistic/mental game. Peter*s levels of diagram, employing different types of propositions or linguistic entities, can never capture the rules by which the game is played. Can never capture the meaning of the linguistic pieces. The game of *inference* is a product-in-development that our species has worked on very successfully for many thousands of years. Its evolutionary usefulness is beyond doubt.
It is also beyond doubt that *inference* is not the only successful game in town! The *games* of love and of war, for example, generally claim higher places in the pantheon of evolved human activities. But as academics, one of our favorite games * besides the game of inference -- is the game of *modeling.* When we play our modeling game about the game of inference, when we attempt to model inference, we call the formal model a *logic.* But it would be unfortunate if we ever thought that modeling IS inference, or that any model or set of models could EXHAUST or entirely capture the rules or meaning of inference, or that we fully understand the rules and criteria for the game of MODELING itself. The river of thought is in flux, Heraclitus would have reminded us, and our models (and even our ideas about modeling) are mere flotsam in the spring snowmelt. The major modern advance over Heraclitus is Darwin: we now find it very useful to think that our inferences, our models, and our
ideas about inference and modeling are all evolving in useful ways. But only time will tell. We have to see how useful our logics are at solving discrete problems.
My three major points are connected. It is generally useful to distinguish inferring conclusions from providing causal explanations. The observable world is contingent and causal because we can imagine it being other than it is, while the linguistic models we use to describe that world are held together internally by our concepts of meaning and necessity. But even those concepts are to be judged by their usefulness, and we should always keep an open mind about modifying them. That is, after all, one of the main things we academics get paid to do! (And I do believe that academies are generally useful institutions in the long run.)
If these reflections are not as hard and concrete as some would like, perhaps it is fitting to commend the words with which Peter began this thread: these are, more than we care to think, merely *summer night dreams.*
Vern.
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Vern R. Walker
Professor of Law
Hofstra University School of Law
Hempstead, New York 11549