[lit-ideas] Re: Patty Duke & The Apriori

  • From: Robert Paul <rpaul@xxxxxxxx>
  • To: lit-ideas@xxxxxxxxxxxxx
  • Date: Tue, 28 Jul 2009 14:20:05 -0700

I wrote, reply to Walter, who'd said otherwise

...How does the 'concept' of an argument [disallow] already believing the conclusion before providing the premises that support it?

I'd thought this would have been uncontroversial, but Walter subsequently defended it, a defense that I'll ignore for now, and take up in a later post.

Skirmishes: One often believes that the conclusion of an argument is true, and provides an argument for it for those who disagree. Ideally, if the one who disagrees accepts the premises that make up the argument, he or she will come to believe the conclusion too. The argument need not be a 'formal' one; Harvey could have shown Descartes that the blood circulated as he, Harvey, said it did, and not as Descartes had thought it did, by empirical means. (This would have required an anachronism blocking device.) 'The reason I say it does, René, is that...well, see for yourself.' Of course H must have believed his view was right before trying to convince D of it.

Now, Eric writes

Philosophical Lightweight Intrusion: What is there to believe about conclusions?

Many conclusions are expressed via 'that' clauses, e.g., that water is incombustible, and if this comes at the end of an argument, then that water is incombustible is surely a candidate for belief.


How do arguments, whatever they are, relate to (a) notions that have great descriptive value but no predictive value (e.g., the four humours); notions that have little descriptive value but great predictive value (e.g., calculus applied to fireworks); and notions that supply both (e.g., psychological profiles of particular criminals)?

Great question. In a now-neglected paper, 'On the Symmetry Between Explanation and Prediction,' [Philosophical Review, 1959] the late Russ Hanson deconstructs Karl Hempel's once-famous claim that explanations and predictions are 'symmetrical.' Hempel had said, in brief,

'. . . An explanation . . . is not complete unless
it might as well have functioned as a prediction;
if the final event can be derived from the initial
conditions and universal hypotheses stated in the
explanation, then it might as well have been
predicted, before it actually happened, on the basis
of a knowledge of the initial conditions and general
laws ... ['The Function of General Laws in History,'
Journal of Philosophy, 1942]'

'This* is the ideal situation which Hempel describes in the quotation
above. In fact, the history of science presents very few examples of
disciplines wherein this optimum state of affairs has actually been
achieved. Aristotle's cosmology, for example, while it certainly did
explain the perturbations of the celestial bodies, could not begin to
predict where any planet might appear on any particular day. None-
theless, his "word-pictures" undoubtedly made the cosmos seem more
intelligible to his contemporaries, and in some sense of "explanation"
this counts as an explanation. To deny this would be merely to legislate
on how "explanation" ought to be used for certain logical or philo-
sophical purposes. It is to leave undiscussed those accounts which
actually have counted in the past, and actually count now, as the
offering of explanations. Granted that Aristotle's explanation of the
cosmos may have been inadequate, it was certainly an explanation;
similarly that a prediction does not turnout true does not mean that it was never a prediction at all. But while Aristotle's heavily-ensphered cosmos tendered an explanation of the planetary motions, it could not render up even a false prediction. It was just not made for that purpose. Is this not after all much like the claim an historian might make of his account of, say, the decline and fall of the British Empire? He can explain it in just that sense in which it is appropriate to explain historical events. But the historian was not even trying to predict this event, or any other event like it. So what he says cannot, anymore than Aristotle's cosmology, be construed as false prediction.
On the other hand, the great astronomers of the ancient world-
Eudoxus, Apollonius, Hipparchus, and Claudius Ptolemy - could to
a remarkable degree predict where planets and stars might appear
at any future date. But each of them explicitly rules out the possibility of ever explaining the physical principles behind the motions of the cosmos. Theirs was the problem solely of forecasting where familiar points of celestial light would be found on the inverted black bowl of the heavens on some later day. Indeed, the subsequent history of planetary theory could be written as consisting in a conceptual struggle between these two opposed attractive forces, the urge to explain and the urge to predict.'

*The retrograde motion of Mars, in 1956.

[Well, there's lots more, but Eric has raised a problem philosophers have struggled with for a very long time, with no clear resolution.]

Robert Paul.
somewhere south of Reed College

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