Shifts Happen
The Work of Thomas S. Kuhn
Fish nor fowl, essay nor outline, this is a
starting point for the afternoon session of the sixtieth meeting of the
Northern California History of Astronomy Luncheon and Discussion Association,
NCHALADA LX. Don't just bring munchies, bring opinions, facts, books. Prepare
to discuss, I have no intention of delivering a monologue.
"Physical concepts are free creations of the human mind and are
not, however it may seem, uniquely determined by the external world.
In our endeavor to understand reality we are somewhat like a man trying
to understand the mechanism of a closed watch. He sees the face and the
moving hands, even hears its ticking, but he has no way of opening the
case. If he is ingenious he may form some picture of a mechanism which
could be responsible for all the things he observes, but he may never
be quite sure his picture is the only one which could explain his observations.
He will never be able to compare his picture with the real mechanism and
cannot even imagine the possibility or the meaning of such a comparison.
But he certainly believes that, as his knowledge increases, his picture
of reality will become simpler and simpler and will explain a wider and
wider range of his sensuous impressions. He may also believe in the existence
of the ideal limit of knowledge and that it is approached by the human
mind. He may call this ideal limit the objective truth."
--Albert Einstein, The Evolution of Physics
The emphasis on "may" in the quote is mine. Philosophers have known
for hundreds of years that the connection between science and truth is
problematic. Scientists have, for the most part, ignored them and continued
their search for reality. Even philosophers, in their everyday life, seem
to behave as if they lived in a real world that they could learn something
about. Hobbes utterly demolished the principle of induction, proving that
no matter how many times you see something it's no proof that you'll see
it next time. Then he admitted that he followed that demolished principle
all the time.
Background
The fundamental problem in the philosophy of science may be addressing
the question "Why does science work?". Philosophers have proposed a number
of reasons, and scientists have largely (and perhaps rightly) ignored
them,
It may be inevitable that scientists don't see themselves interwoven in
their perception of the world. Our eyes don't see themselves, our nose doesn't
smell itself. Why shouldn't our brain, the instrument we think with, be equally
unconscious of itself? And why shouldn't the same be true of our society's
brain, the scientific community.
Plato
The universe we see isn't real, or perhaps is only a small part of
what's real. Pure thought finds it all. Observation plays no part.
Aristotle and the Catholic Scholastics
There's a real world, created perfectly. Part of that perfection
is the fact that it's comprehensible.
Induction
Famous example: All swans are white. Every white swan we see confirms
this. But how do we know we just haven't happened to run across the black
swans yet? Can we ever know for sure? Logically equivalent, the statement
"All non-white objects are not swans". This statement (and so its logical
equivalent, all swans are white) is confirmed by finding a black crow. Why
doesn't seeing a black crow confirm my belief that all swans are white?
Even worse than confirming instances that don't strengthen belief
in the hypothesis, there are ways a confirming instance can make any rational
person doubt the truth of the hypothesis it confirms. All men are less
than twenty feet tall. Every man I've ever met is less than twenty feet
tall, thus confirming my hypothesis. Then I meet a man nineteen feet eleven
inches tall. Another confirming instance, but I suddenly have doubts.
Falsification
Karl Popper and Sherlock Holmes
: "... when you have eliminated the impossible, whatever remains,
however improbable, must be the truth".
But how do we know we've thought of all the improbable possibilities?
We can't, there are generally an infinity of them Some of those possibilities
can be convincingly argued against, but not disproven. Creationism and
Last-Tuesdayism provide a couple of examples. A clever creationist will
point to Adam's navel in a painting, and compare it to the fossil record.
You can't prove that the universe wasn't created in 4004 BC with the fossil
record and all other evidence of antiquity put there at that time for the
sake of artistic completeness. You also can't prove that the universe wasn't
created Last Tuesday at 4:37 PM, Pacific Time, with all the evidence of
age (including our memory of last Monday) created at the same time.
Taking exception
None of the ideas philosophers of science have come up with provide
a convincing demonstration that science should work, or even a recipe for
doing science. Kuhn noticed this and, as an historian, addressed the question
of just what it is that scientists do that works so well.
In The Unnatural Nature
of Science Lewis Wolpert asks if we could have had a different science
if historical conditions had been different. "Would a biology not based
on cells and DNA have been possible? Would the periodic table or carbon
chemistry never have emerged?" He's clearly implying that science is converging
on some pre-existing "objective truth" or description of the "real world",
but I was just reading about the evolution of the eye in
The Blind Watchmaker
. There doesn't have to be a pre-existing engineering drawing of
the eye in God's mind or in some Platonic heaven. The eye is extremely
useful, and reachable by a series of steps that can come about without
a plan. So, the octopus and the ocelot both developed eyes through entirely
different historical circumstances that came to the same essential result.
Similarly, the periodic table. It's such a useful idea for organizing
facts about chemistry that it likely would have ended up an essential part
of science in any event. It didn't need to be a fundamental "real thing",
and in fact we now now that it isn't a fundamental thing at all, but rather
a consequence of some underlying physics. Or at least we think we know
that.
The mindset that Kuhn was taking exception to is well summarized
in A Physicist's Guide to Skepticism
by Milton Rothman. "The contents of a science change over time as
a result of the accretion of new knowledge" and "[Galileo] had the correct
fact in hand, but was powerless to change the beliefs of others with
that fact. His adversaries, on the other hand, had only beliefs and powers."
The Copernican Revolution
, written long before The Structure of Scientific
Revolutions
, is an historical look at an example of scientific progress that
isn't a steady and logically driven march toward understanding the truth.
Here we find a good description of the Aristotelian and Scholastic beliefs,
with support for why they were believed.
We then find a detailed description of the process by which new ideas replaced
old ones. We see that the new ideas were better, far better, but not better
for obvious reasons that can be decided by some set of universal rules.
The primary focus here is history, not philosophy. Nevertheless, we get
a look at two main points of Kuhn's philosophy of science: That a scientific
revolution is real progress, and that it's not as simple as new good beliefs
replacing old bad ones.
Thomas Kuhn observed that science, as it's actually practiced, isn't
the logical and cumulative building up of a true picture of the world
that it was generally believed to be. He showed that there is no fixed,
defined algorithm for deciding between competing scientific paradigms.
This was taken by many scientists and many nihilists to mean that any theory
was as good as any other, but Kuhn clearly meant no such thing. Quite the
opposite, he said the thing that most clearly differentiated a science from
any non-science was that science progressed.
Kuhn sees progress as the most readily discernable feature of science as
compared with other enterprises. The only other field he sees this progress
in is art, and that only in the period during which art was judged by its
ability to accurately represent visual perception of reality.
Kuhn is quite neutral on whether or not there is an objective truth or reality.
His main point is that scientific progress is a continuing refinement of our
ideas about what might be the case. He says there's no single criterion for
selecting one theory over another, not even success at predicting phenomena.
That certainly plays a role, but so do simplicity, elegance, even style. The
only judge is the consensus of the scientific community, and that clearly
changes so it can't be used in advance to decide one theory over another.
He's by no means a relativist though. He shows that, in retrospect, the
scientific community ends up choosing wisely, and clearly states that progress
is a characteristic of science as in few other fields. Kuhn doesn't say that
choosing, say, Copernicus over Ptolemy isn't fully justified. He only points
out that the reason it's the right choice isn't obvious or decidable by a
strictly defined method or algorithm.
Agree or disagree with Kuhn, we still use the word "paradigm" with his meaning.
He gave us a new way of thinking about scientific revolutions, a paradigm
shift in our views about paradigm shifts.
Kuhn drew a strong (too strong?) distinction between normal science
and revolutionary science. His critics thought he was calling normal science
drudge work, and revolutionary science irrational. Was he?
It's no great surprise that, after Structure
, much of Kuhn's work was explanation and defense of
Structure
.
I'll focus on two people among those Kuhn takes exception to, and I'll
choose two from opposite viewpoints in a way that lets me buy only one
book: For and Against Method
, by Imre Lakatos and Paul Feyerabend. Lakatos called Kuhn "elitest",
both believed him relativist. Feyerabend thought this a good thing.
"I am rereading Kuhn's The Copernican Revolution. A marvelous
book ...". Feyerabend. With friends like these, who needs enemies.
The essay Reflections on My Critics in The Road
Since Structure
is Kuhn's reply to Lakatos, Feyerabend and others.
I tried to type Postmodern Encounters, the name of the series of tracts
containing Thomas Kuhn and the Science Wars
by Ziauddin Sardar. My typing fingers insisted on "sludge". I'd like to
return this "book" and deprive its author of a royalty, but it's not in its
original condition. It's had too many postmodern encounters with the walls
of my apartment.
Sardar and his ilk bear much of the blame for the thorough and general misunderstanding
of Kuhn's works. Sardar focuses on Kuhn's exposing the fact that science isn't
the cut and dried logical enterprise some would like it to be, and totally
ignores Kuhn's repeated support for the fact that science progresses and
his attempts to figure out why.
On a side note, Sardar disparaged Popper's The Open Society
and its Enemies
as an "anti-communist opus". I could be wrong here, it's been too many
years since I read it as a young teenager, but I remembered Open Society
as anti-Nazi, anti-Communist, anti-totalitarian in general.
Perhaps better than Sardar (I've only read the review, not the book), a postmodern
take might be gotten from Thomas Kuhn: A Philosophical
History for Our Times
by Steve Fuller. This was reviewed in the September 2000 issue of Scientific
American.
Thomas Kuhn (Philosophy Now Series)
by Alexander Bird is a much more pertinent and balanced criticism of
Kuhn's work.
Science doesn't divide so neatly as Kuhn supposed between the normal
and the revolutionary. The Copernican revolution is at one end of a spectrum,
accurately measuring the parallax of nearby Cepheids is at the other. Much,
perhaps most, science is in between, neither normal nor revolutionary.
And much that is revolutionary didn't involve a fight. Stretching the
political analogy a bit further, Crick's unravelling of the structure of
DNA could be called a bloodless coup.
Kuhn's contention that scientists using different paradigms see different
worlds gets plenty of criticism in Bird's book. He analyzes some psychology
and philosophy of seeing, and concludes that Kuhn went too far here.
I could make the entire session a discussion of this book and still run
out of time. I've barely scratched the surface here.
Bibliography
The Copernican Revolution, Thomas S. Kuhn, Harvard University Press,
1957
The Structure of Scientific Revolutions, Second Edition, Enlarged,
Kuhn, University of Chicago Press, 1970
The Essential Tension: Selected Studies in Scientific Tradition
and Change, Kuhn, University of Chicago Press, 1985
The Road Since Structure, Kuhn, ed. by James Conant and John Haugeland,
University of Chicago Press, 2000
Thomas Kuhn (Philosophy Now series), Alexander Bird, Princeton University
Press, 2000
The Blind Watchmaker, Richard Dawkins, Norton, 1996
The Complete Sherlock Holmes (The Sign of the Four), Sir Arthur
Conan Doyle, Doubleday, 1930
The Evolution of Physics, Albert Einstein and Leopold Infeld,
Simon and Schuster, 1938
Thomas Kuhn, a Philosophical History for our Times, Steve Fuller, University
of Chicago Press, 2000
A New Paradigm for Thomas Kuhn, a review of Fuller's book, Chet Raymo,
Scientific American, September, 2000
For and Against Method, Imre Lakatos and Paul Feyerabend, University
of Chicago Press, 1999
The Open Society and its Enemies, Karl Popper, Princeton University
Press, 1971
A Physicist's Guide to Skepticism, Milton A. Rothman, Prometheus,
1988
Thomas Kuhn and the Science Wars, Ziauddin Sardar, Totem Books, 2000
The Unnatural Nature of Science, Lewis Wolpert, Harvard University
Press, 1993
Webliography
Thomas Kuhn
, a biography and some links by Frank Pajares of Emory University.
http://www.emory.edu/EDUCATION/mfp/Kuhnsnap.html
Stuttering Research
. Why East Carolina University has a bunch of Thomas Kuhn links in their
stuttering research pages, I have no idea. But they're at
http://www.ecu.edu/csd/kuhn.html
Scientific
American review
of Steve Fuller's book.
http://www.sciam.com/2000/0900issue/0900reviews1.html