Are Graber's position and mine so different?

John L.McCreery (jlm@TANUKI.TWICS.CO.JP)
Fri, 17 Dec 1993 16:32:28 JST

I think that Bob Graber's position and mine are closer than he thinks.
When he writes that,

"Science does not claim to get at the absolute *Truth*; it is simply our
best way of trying to find out what is true. For truth-seeking, we have
no alternative to an unending interaction of evidence and reason.
Giving up on Absolute Truth gives us our best access to plain old truth,
which is what science modestly seeks,"

I find myself saying, "Yes. Yes. And yes, again." The one word I'd
quarrel with is "access." If I wrote the sentence my phrase would be
"our best *approach* to plain old truth."

As I see it, truth is a limit that science approaches asymptotically. We
can aways get closer; we'll never get there. Thus, on currently
available evidence, I will certainly agree, for example, with the "fact"
that "the space shuttle crashed." An alternative view, that, for example,
that the world I experience is a virtual reality that will disappear when
I "die" and take the helmet off, is implausible in the extreme. Can I rule
it out absolutely? I never said I was God.

If this view is correct, both "Science is a discovery procedure" and
"Science is a decision procedure" are ruled out: the first because we
never actually reach the limit; the second because we can't say what
the limit is. We can still look for criteria that make one theory better
than another because we have good reasons to believe that the better
theory is a closer approximation to *Truth*. That may seem to be a
peculiar claim (If we don't know the *Truth*, how can we judge which
theory is closer to it?), but it fits well with the history of science as I
understand it.

Consider, for example, theories of planetary motion. In _The
Metaphysical Foundations of Modern Science_, E.A. Burtt observes
that Ptolemy's theory of epicycles was a closer empirical fit to
observable facts than Copernicus' helicentric theory; until the 19th
century when telescopes powerful enough to observe stellar parallax
were developed. Until these telescopes were developed, the parallax
Copernicus' theory predicted could not be observed, apparently
contradicting the theory. In predicting planetary motion itself, the two
theories were equally accurate. Copernicus' was, of course, the simpler
theory. That made it better by Occam's razor. More important for its
acceptance was the spread of Neo-Platonist mysticism which assigned a
"central" place to the Sun. Telescopes provided new evidence and
Newton's mechanics a better way to account for it. Then came
Michelson-Morley, Einstein, and non-Euclidean geometries and a
theory that was better still. Is this the last word in physics? Tell it to
the guys who are mussing around with quarks and cosmic strings.

Cheers, John McCreery (