Bonus Appendix: Kuhn and
Science
Mark
Mitchell and Janina Jolley
© 2007-2021
All rights reserved.
Not everyone accepts the idea that
science has made successful, steady progress. Most notably, Kuhn (1962) in his
book “The Structure of Scientific Revolution,” pointed out that if science
progressed step-by-step, newer scientific models of reality would be merely
more refined, more evolved versions of older models. But they aren’t. Instead,
new models are radically and revolutionarily different from older models. For
example, the idea that the earth revolves around the sun is not a refined
version of the previous view that the sun revolves around the earth, and
One obvious implication of the newer
paradigm being radically different from the older paradigm is that switching
from the old paradigm to the new paradigm does not involve taking a small step
but instead involves taking a quantum leap. A less obvious implication of the
newer paradigm being radically different from the previous paradigm is that the
previous paradigm may have little to contribute to the newer one. If the older
model has little to contribute to the newer model, scientists may, rather than
building on to the previous paradigm, bulldoze it. If scientists bulldoze the
old paradigm, all that step-by-step progress made by the old paradigm is also
swept away. By pointing out that revolutionary change does occur and by arguing
that the steady, evolutionary, routine work that scientists do is swept away
during the revolution, Kuhn attempts to lay waste to the textbook-created
illusion that science makes lasting, steady progress.
Kuhn did not stop at saying that progress in science occurs
by changing from one paradigm to another, what he calls a paradigm shift. Kuhn
also argued that scientists, when
deciding whether to leap from one paradigm to another, considered factors other
than the evidence.
The problem, according to Kuhn, is that all scientists,
rather than being completely open-minded, subscribe to a paradigm. According to
Kuhn (1970), scientists need to subscribe to a paradigm because "... something like a
paradigm is prerequisite to perception itself. What a man sees depends both
upon what he looks at and also upon what his previous visual-conceptual
experience has taught him to see. In the absence of such training there can
only be, in William James' phrase, a
bloomin' buzzin' confusion.” To see what Kuhn is talking about, look at
this ambiguous
figure. If you don’t have a viewpoint, you can’t make sense of what you are
seeing: It’s almost as if you’re not seeing anything.
So, suppose you and your friends have a point of view—you all see the vase. Why do you all see the vase? It could be that some of your unspoken assumptions about the world make all of you see the vase. What would make you give up seeing the vase and see two faces instead? If we told you to look more closely at the dark part of the figure, you would probably still hold to your view that it was a vase. However, if your friends all decided that the image represented two faces, you might change your viewpoint. Similarly, Kuhn believes that the acceptance of a new paradigm is influenced not only by the evidence but also by what influential members of the scientific community believe. One reason he believes that community opinion is important is because he believes that some scientists put their faith in a new paradigm well before the evidence warrants it, whereas others hang on to the old paradigm even after the evidence warrants a move to the new paradigm.
A second reason Kuhn believes that community opinion is so important is because he believes that paradigms cannot be compared based on evidence. Like our vase/faces picture, you can’t say that one paradigm is better than another. According to Kuhn, scientists from two different paradigms can’t, based on the evidence, agree that one paradigm is better than the other because they can’t agree on the evidence: The paradigm determines the evidence and they have different paradigms.
How can paradigms affect what evidence scientists see? The paradigms affect observation because scientists don’t see objects for themselves; instead, scientists see objects as examples of particular concepts (scientists try to put observations into “conceptual boxes”)—and the paradigm determines what those particular concepts are. For example, if your paradigm makes you see the moon as a planet, the moon’s circling the earth is relevant to understanding how the planets move around the earth; if you don’t see the moon as a planet, the moon’s circling of the earth is irrelevant to understanding planetary motion. Thus, evidence that is convincing to followers of one paradigm may be seen as irrelevant or even unscientific to followers of another paradigm.
Although Kuhn makes some plausible arguments, most scientists disagree with Kuhn’s thesis that the choice of a paradigm is not rational. If paradigms can’t be compared, we couldn’t say that the view that the earth revolves around the sun is a better paradigm than the view that the sun revolves around the earth. If scientists are choosing paradigms for nonrational reasons, either scientists have either have correctly chosen to abandon older paradigms by accident or scientists should go back and revisit rejected paradigms. If scientists from a different paradigm don’t look at the evidence from a rival paradigm, the scientists who believed the sun revolved around the earth would deny the evidence that the earth revolves around the sun. However, people who did believe the sun revolved around the earth changed their minds after looking at the evidence. They did not deny the evidence. Furthermore, research shows that most scientists, regardless of their biases or theories, agree on the basic observations.
Kuhn, at least at times, seems to agree with the scientists. Kuhn himself has said that science is rational (Haack, 2003), that paradigms can be compared, and that science is not mob rule. Although scholars get frustrated trying to find out what Kuhn really meant (some even complain that there are two Kuhns, a radical one and a moderate one), Kuhn’s impact was determined by what people thought he said. By some standards, Kuhn’s was the first real attack on science—and people may have read more into his attack than he meant. It’s possible that Kuhn merely meant to remind people that science is done by imperfect humans who make subjective decisions (sometimes based on tradition, biases, politics, or funding) about what’s important to study, and who come up with explanations that, although seeming to be true at the time, will later be replaced by a different explanation. If so, Kuhn is like the farmer who prayed for rain and got a flood. Kuhn’s book led to a flood of criticisms of science. Given that almost all criticisms of science owe something to what people thought Kuhn said, let’s use an analogy to understand what many people consider to be Kuhn’s view of science.
In this analogy, scientists are like people exploring a dark cave. At first,
the explorers make no progress because they can’t see anything. Eventually,
however, someone devises a helmet that allows the explorers to see. The problem
is that the helmet doesn’t just light up the cave: The helmet highlights some
objects, filters out the color of other objects, and completely filters out
sounds.
Given that the
explorers started out not seeing or hearing anything, the original explorers
don’t see any problems with the helmet. As they teach their followers about how
to use the helmet, they also enthusiastically tell their followers stories of
people making great discoveries using the helmet. The new group comes away with
appreciation for the helmet and a desire to use the helmet to make even more
discoveries.
The new group
members are not a bunch of skeptical, independent, creative “out of the box”
thinkers. Instead, they are happy to work within the paradigm’s box. Like a
family physician, they are skilled at applying what they know to new cases. Put
another way, if you think of science as a game, you can think of working within
a paradigm as working on a crossword puzzle that has some of the entries
already filled in—all you have to do is follow the clues and fill in the
remaining entries. Note that you can do very well in this puzzle-solving task
without being an independent, skeptical thinker. Indeed, accepting other
people’s entries can help you solve the puzzle faster—as can not doubting the
validity of the clues.
To go back to our
cave analogy, imagine that the cave contains many objects shaped like cylinders
but that the helmet (the paradigm) limits the explorers to looking directly
down on the tops of the cylinders. Consequently, instead of seeing these
objects as three-dimensional cylinders, the explorers see the objects as
two-dimensional circles (see the next figure)[1].
Reality Old
model of reality New model of reality
(View from side) (View
from top)
Figure 1-3: Reality is many-sided; a fact that simple, one-sided models do not capture.
As long as the explorers focus on the tops of the
cylinders, the explorers will feel they are making progress in better
understanding and mapping these objects. Although they run into evidence that
counters their “circle view” (they bump into the sides of the cylinder; the
circle seems to float; and they hear sound echo off the cylinder), they dismiss
that evidence. For example, they may claim that the sides are not part of the
circle (or at least not a part worth studying), the apparent floating is due to
measurement error, and that hearing echoes in a cave is not a scientific way to
study objects. As long as all the investigators—by examining events that fit
the model while ignoring events and findings (anomalies) that do not fit the
model—go along with the main viewpoint, the investigators appear to make steady
progress. Without dissent, investigators may believe they are being objective
when they are really under the influence of a paradigm—and that shared paradigm
determines both what should be studied and how it how it should be studied.
As time goes on,
the problems with the old paradigm become increasingly obvious. Yet, despite
the old model’s problems, the people who have been working on the old model all
their professional lives, the people who have become famous by telling people
how well the model explains reality, are not willing to give up on the old model.
Younger
investigators who have not invested much of their life on the old model may
notice flaws in the old model. If a strong leader urges them to abandon the old
model and replace it with the leader’s new model, these younger investigators
may follow this rebel leader. To go back to our cylinder analogy, let’s assume
that a younger group of cave explorers focus on one of the cylinder’s sides and
decide that the cylinder is nothing like a circle, but instead is just like a
rectangle. Unfortunately, the new paradigm does not represent as much progress
as the rebels believe for two reasons.
First, the
rebels’ eagerness to destroy the old model leads to their abandoning,
denigrating, and denying some of the knowledge discovered when people based their
investigations on the old model. By saying that the cylinder is nothing like a
circle, they lose all the knowledge gained from earlier investigations of the
cylinder’s top. By throwing out not just the old model but also the research
that was done on that model, the rebels are, in a sense, throwing the baby out
with the bathwater.
Second, by saying that the cylinder is just
like a rectangle, the rebels’ model is still a flawed, oversimplification of
reality. Instead of adding to the old, oversimplified (circle) model to make a
more complicated, complete, and accurate (circle and rectangle) model, they have replaced it with a new,
oversimplified, and flawed model.
Although the new
model may be as flawed as the old model, politics—or, in some cases, mob
rule—may allow the rebels to get others to join them in rejecting the old model
and replacing it with their new model. To succeed, the rebels will probably
need a charismatic leader who has good political skills. The rebels will make
persuasive speeches, write persuasive articles, praise their followers, and
condemn their opponents. Once in power, the rebels will use their political
power to make it easy for their followers—and harder for their opponents—to get
grants, publications, honors, and jobs.
As we hope you
can see from our analogy, many people see Kuhn as objecting to the view that
science is an unbiased, apolitical, steady march toward objective truth. Many
feel that Kuhn has shown that science is political: Scientists, like junior
high students, claim to be skeptical and independent but are really trusting
and wanting to be popular with the coolest group.
Scientists
point out two problems with the argument that Kuhn’s research on paradigms
shows that science is political. First, Kuhn’s
finding that paradigms have serious flaws does not prove that scientists are
political. To the contrary, the only reason people know about the flaws in
paradigms is that scientists found those flaws. Thus, rather than being
conforming political animals, scientists, by being skeptical and by making
testable predictions, correct their own errors, and avoid being overly
committed to an erroneous paradigm.
Second, Kuhn’s finding that scientists do not
all adopt the new paradigm at the same time does not prove that political
pressures were at work. Indeed, we would not expect independent scientists to
change to the new paradigm all at the same time. Just as reasonable,
independent minded people might differ in terms of whether to rebuild or
relocate after their neighborhood was damaged in a storm, independent,
skeptical scientists could differ in terms of how certain they needed to be
before abandoning one paradigm for another.
Some cynics, in
addition to seeing Kuhn’s work as supporting the idea that science is
political, also see Kuhn’s work as supporting the idea that scientific progress
is an illusion. They see the illusion of progress as the result of a new,
inaccurate viewpoint replacing—rather than building on—the old viewpoint.
Scientists also
object to the suggestion that Kuhn’s work shows that scientific progress is an
illusion because in every case of a paradigm shift, the shift has been toward a
more accurate model. For example, the model that the earth revolves around the
sun is more accurate than the model it replaced—the model that had the sun
revolving around the earth. As a consequence of newer, better paradigms
replacing older paradigms, chemistry, biology, and physics have made tremendous
progress over the past 500 years. Thus, although scientists concede that their
models are not perfect, scientists point out that their current models are more
accurate than either older models or common sense.
Whereas many scientists have dismissed the claims that
science is political and that science does not really progress, some critics of
science have extended both of these claims. In extending the idea that science
is political, some have argued that science is affected by society’s politics.
Specifically, some critics view science as a political tool that makes one
group’s viewpoint seem true. For example, the Nazis attempted to discredit
physics by calling it the “Jewish physics” (Haack, 2004). Similarly, a few
feminists have attempted to discredit traditional science by calling it a “male
viewpoint” (Haack, 2004).
In extending the idea that science does not march
toward objective truth, some have argued that there is no objective truth—only
different viewpoints[2]. In terms of our cave-cylinder analogy, their argument
would be either (a) that there is no cylinder or (b) that there is no way to
objectively describe the cylinder—any description would be colored by one’s
biases.
Contrary to the cynics, most people agree that (a) there is a real
world and that (b) science is the best, and the most
objective, tool we have to understand that world. Almost everyone would agree
that science has allowed physics, chemistry, and biology to progress at a rapid
rate. Hardly anyone would argue that we could make more progress in
understanding our physical world by abandoning science and going back to prescientific beliefs and methods, such as alchemy or philosophy (Dawkins,
1998). Indeed, it seems like every field wants to be labeled a science—from creation science to
handwriting science to library science to military science to mortuary science
(Haack, 2003).
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