SUO: RE: Question about Example in KR Book
John:
You said: "What you are describing is *not* the nominalist answer, it is the
realist answer". Well, although my list of publications is practically
non-existent, and yours is impressively extensive, I did write my doctoral
dissertation on Quine, and have been interested in the realism/nominalism
issue for a long time. I say this to make the preliminary point that
something funny must be going on here, since neither of us are amateurs when
it comes to this issue.
Since there have been several others in this forum who have expressed an
interest in what the difference between realism and nominalism is, I don't
think I should leave your statement unanswered. That would just puzzle those
who have read my extensive (some would say "too extensive") earlier comments
on nominalism over the last several months.
On the other hand, since there has been a cacaphony of voices objecting to
lengthy and/or frequent postings on topics not directly related to the
objectives of this working group (by persons whom I believe would regard a
discussion of realism and nominalism as falling in that category), I'll
leave the last posting to you, and discuss this issue no further.
Your definition of "realism" ("Once we have ......" below.) claims the
middle ground between extreme realism and extreme nominalism, which are the
versions I was defining. This grabbing of the middle ground so trivializes
the realism/nominalism issue that Richard Rorty (whom we both agree is a
nominalist) would be perfectly happy with your brand of realism -- as would
Quine, another nominalist! In claiming that middle ground, by definitional
fiat, you have not solved an important philosophical problem, but rather
covered it up.
We are talking past one another, I believe, because I have been discussing
realism and truth (to borrow the title of a book by Dummett), and you have
been discussing realism and methodology.
From the truth perspective, realism is associated with a correspondence
theory of truth, leaving coherence as the alternative truth theory for such
nominalists as Quine and Rorty, Kuhn and Feyerabend. For the realist, single
sentences stand alone before the "tribunal of experience". The sentence
"That snow over there is white" is true if and only if that snow over there
is indeed white. For the nominalist, as Quine pointed out, it is theories as
a whole, with their internal coherence, that stand before that tribunal. (An
interesting point to keep in mind when considering Popper's falsification
theory. What component hypothesis of a scientific theory is actually being
falsified?) The Quinean/nominalist position seems to give us so much wiggle
room that we lose contact with reality, and end up able to justify any
statement provided we're willing enough to make adustments in other
statements. How to do justice to the notion that true descriptive statements
are true because they describe what reality is really like, while also doing
justice to the Quinean/nominalist insights mentioned, is what I consider the
central question of both metaphysics and epistemology today.
You, on the other hand, focus on realism and scientific methodology. But who
could possibly object to testing hypotheses before putting your faith in
them? If that is what realism is, then there is no alternative that a
serious person could champion. What, then, are apparently serious people
like Quine et. al doing? Are they nominalists because they are stupid?
The truth perspective and methodology perspective on realism vs. nominalism
do come together. They come together when we ask ourselves what "testing
hypotheses" means. The more stable the "background theory" to the testing of
a specific hypothesis is, the more that test is a test of that hypothesis,
and the more that hypothesis can be falsified by direct confrontation with
experience. That is because, although experience is always interpreted
experience, the interpretation is well established, and highly stable. On
the other hand, the more our experiments are conducted in a milieu of what
Kuhn called "revolutionary science", the more those tests apply to clusters
of hypotheses instead of individual hypotheses, to "theories" rather than
"predictions". During periods of revolutionary science, the reassuring
solidity of Popperian falsification fades into fear, uncertainly and doubt.
For if an experiment turns out other than expected, what is it that was
falsified? If Quine is right, the most obvious candidate hypothesis might
continue to be held as true, by making adjustments elsewhere.
In work-a-day science, we are usually at neither extreme. We are usually
doing neither revolutionary science nor science so "normal" (in Kuhn's
terminology) that one and only one hypothesis is a candidate for
falsification by a scientific experiment. If the apparently falsified
hypothesis is a pet hypothesis of the principal scientist (if his reputation
and promotion within his department depend on its truth), that scientist
will try mightily to find another explanation for the outcome of the
apparently falsifying experiment. If experimental error is ruled out,
another explanation means deflecting the results of the experiment onto a
different hypothesis, some other component of the "background" theory to the
experiment.
This happens all the time, but your description of scientific methodology
fails to acknowledge it for what it is -- a situation which the common
sense, "with science, we test our hypotheses, and so we're in touch with
reality" brand of realism really doesn't explain at all.
So in the end, I claim it is possible to acknowledge the force of the
nominalism presented by Kuhn, Quine et al, and still put one's trust in the
laws of science and technology, to get in one's car and drive to the
doctor's office where one will be treated with a possibly invasive
technology that one understands very imperfectly.
Conclusion: what I called "nominalism" and you called "realism" is
nominalism, pure and simple, from the realism/nominalism and truth theories
perspective. It is also part of scientific methodology. But rather than
saying that scientific methodology is realism, pure and simple, I believe I
have shown that scientific methodology is fully compatible with the
nominalism of Quine et al. Scientific methodology is more realist the more
stable background theories to an experiment are. It is more nominalist the
less stable those background theories are.
To avoid "tarnishing" the good name of scientific methodology, should we
drastically misrepresent what "realism" means vis-a-vis "nominalism", as you
do? This is an ancient and still current central issue in metaphysics and
epistemology, and I will not agree to so misrepresent it.
Should we present so over-simplified a picture of scientific methodology as
to leave others wondering how an historian of science like Thomas Kuhn, not
to mention world-class philosophers of science like Feyerabend and Quine,
could have failed to realize that scientific methodology gives the lie to
their nominalism? I will not agree to so misrepresent both them and the
nature of the scientific method. Nor will I call them names, such as
"ignorant of scientific methodology".
This forum has turned hostile to contributions such as mine, and to the
discussion of interests such as mine. And so, as I said above, I won't
continue this discussion, and will leave the last word to you.
With great respect for your contributions, but disagreeing with you on this
issue.
Tom
-----Original Message-----
From: John F. Sowa [mailto:sowa@bestweb.net]
Sent: Sunday, November 23, 2003 10:35 AM
To: Tom Johnston
Cc: cg@cs.uah.edu; SUO
Subject: Re: Question about Example in KR Book
Tom,
What you are describing is *not* the nominalist answer, it is
the realist answer:
> The nominalist would say: the reliable ones do not stand alone.
> They are part of vast systems of laws -- physics, chemistry, biology,
> neuro-sciences, etc. -- which "hang together", which form a consistent
> system of laws. No newly proposed law would be accepted as worthy of
> scientific investigation if it contradicted the established body of
> laws (except in Kuhnian periods of "revolutionary science"). A
> coherence theory of the truth of causal laws.
As soon as you admit that there is any system of description that
reliably describes nature to the extent that you are willing to
risk your life on that description, then you have realism.
Once you make that assumption, the next step is to refine your
procedures for measuring and minimizing the experimental error.
Those are essentially the methods of science. But scientific
methodology is nothing more nor less than a refinement and
extension of the methods that all successful human societies
have used for thousands of years. The ones that had inadequate
methods have been eliminated. (Unfortunately, many good ones
have also been eliminated, but that is how evolution works.)
Bottom line: Nominalism is a dirty word. Don't use it
to tarnish the very effective methodologies of science.
Good science is the method for distinguishing what is real
to the limits of our abilities to observe, measure, and test.
John