PROGRESS IN SCIENCE, REVOLUTION AND RATIONALITY.
1.0 Introduction
The progressive nature of
science is one attribute that is often used to distinguish it from other domains
of human culture like philosophy, religion, art and politics. Improvements and
advances in science are identifiable because of the presence of clear standards
or normative criteria for identifying such progress. Most historians of science
hold the view that progress has no universally recognized and definite meaning
in other fields than in the field of science. But debates on the normative
concept of scientific progress have often led to the following questions: What
is meant by progress in science? How can we recognize this progress? To what
extent, and in which respects, is science progressive? While traditional
philosophers of science like Popper saw “development-by-accumulation” of
accepted facts and theories as the yardstick for progress in science, Thomas
Khun, on the other hand came to realize that traditional accounts, do not bear
comparison with historical evidence.[1] In his book The Structure of Scientific Progress, Kuhn
rejected the notion that scientific progress is cumulative and argued that
there are periods in which such conceptual continuity in normal science were
interrupted by periods of revolutionary science.
In
this paper, we shall first discuss the various approaches taken by different
philosophers of science to define the nature of scientific progress or what
makes science progressive. After which we shall take a closer look at Kuhn’s
approach to scientific progress which lays more emphasis on the revolutionary
nature of science. We shall also explicate terms like paradigm, normal science
and incommensurability which have been popularized by Kuhn’s work.
2.0 Basic Approaches Used in Characterizing
Scientific Progress
There are three general approaches
that have been used by philosophers of science to define scientific progress:
1) the epistemic approach; 2) the semantic approach; 3) the
functional-internalist approach.[2] According to the epistemic
approach, science makes progress precisely when it shows the accumulation of
scientific knowledge. That is, an episode in science is progressive when at the
end of the episode, there is more knowledge than at the beginning. This view
was held by logical empiricists like Rudolf Carnap who sees scientific
advancement as the discovery of higher-level laws or theories which deductively
entail lower-level ones.[3] The semantic approach on
the other hand defines scientific progress in terms of accumulation of true
scientific belief (truth-likeness or verisimilitude) instead of increasing
knowledge. According to Karl Popper, verisimilitude represents the idea of approaching
comprehensive truth. He opines that even when theories are false, they can be
cognitively valuable if they are closer to the truth than their rivals.[4] The third approach, which
is the functional-internalist approach, was a sharp deviation from the other
two approaches. Thomas Kuhn was one of the major philosophers of science who
propagated this approach. He opines that progress is made when a scientific
development succeeds in fulfilling a certain function (such as solving a
scientific problem), where that function is understood in such a way that the
scientific practitioners are themselves in a position to judge whether the
function has been fulfilled.[5] Kuhn rejects the
cumulative notion of progressive science held by both the epistemic and
semantic approach.
3.0 Traditional
View of Scientific Progress
Despite the disagreements between Karl Popper and the
logical positivists, they all shared the following similar views about the
nature of science[6]:
1) Science is cumulative. That is, scientists build on the achievements of
their predecessor (growth in knowledge or truth); 2) Science is unified in the
sense that there exist only one set of fundamental methods for all the sciences
and that all natural sciences are reducible to physics (reductionism) since
everything in the world is made up of the same basic stuff in their complex
combination; 3) There is a distinction between context of discovery and context
of justification. This means that the evidence for scientific knowledge ought
to be evaluated without reference to the causal origins of the theories or
observations; 4) There is an underlying logic of confirmation or falsification
implicit in all scientific evaluations of the evidence for some hypothesis and
such evaluations are value-free, that is independent of the personal
non-scientific view of the scientists; 5) There is a sharp distinction
(demarcation) between scientific theories and other types belief system; 6)
There is a sharp distinction between observation terms and theoretical terms,
and also between theoretical terms and those that describe the result of
experiment; 7) Scientific terms have fixed and precise meaning.
In his book, The
Structure of Scientific Revolution, Kuhn challenged these prevailing views
and rejected them. But before we look at how he refutes these views, we shall
first discuss some central ideas he used in the explication of his idea of
scientific progress or scientific revolution.
4.0 Paradigm
and Normal Science
The most fundamental concept in Kuhn’s philosophy is
that of the scientific paradigm. According to Kuhn, a paradigm is that which co-ordinates
and directs the puzzle-solving activities of the groups of normal scientists
that work within it by setting the standards for legitimate work within the
science it governs.[7]
Kuhn explained what a paradigm meant using two senses: those of paradigm as disciplinary matrix and paradigm as exemplar. He argues that before a
scientific inquiry can even begin in some domain, the scientific community
involved has to agree upon answers to fundamental questions like what kind of
things exist in the universe and how they interact with each other and our senses.[8]
A disciplinary
matrix is a set of answers to such questions that are learned by scientists
in the course of research, and that provide the framework within which the
science operates. It is also referred to as a set of commitments shared by
practitioners of a particular scientific field, including a special vocabulary
and established experimental techniques, as well as accepted theoretical
claims.[9] It is also important that
some aspects of this matrix will consist of practical skills and methods that are
not necessarily expressible in words. Exemplars,
on the other hand, involve those successful parts of science that all beginning
scientists learn, and which provide them with a model for the future
development of their subject. There is no doubt that teaching by example plays
a vital role in the training of scientists, and it is through this means that scientists
effectively acquire and apply new techniques to solve new kinds of problem.[10] According to Kuhn, it is
the existence of a paradigm capable of supporting a normal science tradition
that distinguishes science from non-science. Newtonian mechanics and wave
optics constitute paradigms and qualify as science. Much of modern sociology
lacks a paradigm and consequently fails to qualify as science.[11]
Most science is what Kuhn calls “normal science”,
because it is conducted within an established paradigm. He portrays normal
science as a puzzle-solving activity governed by the rules of a paradigm.[12] It involves detailed
attempts to articulate a paradigm with the aim of improving the match between
it and nature. A mature science is governed by a single paradigm which
co-ordinates and directs the puzzle-solving activity of normal scientists that
work within it. Prior to normal science is what Kuhn calls “pre-science” in
which there is no consensus on any particular theory, though the research
carried out can be considered scientific in nature. They are the disorganized
and diverse activity that precedes the formation of a normal science.[13] An example of a normal
science is the coming up with more detailed predictions and experimental determinations
of the paths of planet and other heavenly bodies.[14] Periods of normal science
provide the opportunity for scientists to solve the difficult details of a
theory.
4.1 Crisis
and Revolution
Kuhn is very critical of Popper’s
falsification, according to which scientists do and should abandon any refuted
theory. For Kuhn, the knowledge of falsifying instances is not enough to make
scientists abandon their theories.[15] He recognizes that
paradigms will always encounter some difficulties or anomalies. But the mere
existence of anomalies (unsolved puzzles) within a paradigm does not constitute
a crisis.[16]
Some anomalies may be dismissed as errors in observation, others as merely
requiring small adjustments to the current paradigm that will be clarified in
due course. Some anomalies resolve themselves spontaneously, having increased
the available depth of insight along the way. But no matter how numerous the
anomalies that persist, Kuhn observes that the practicing scientists will not
lose faith in the established paradigm for as long as no credible alternative
is available. It is only under special sets of conditions that the anomalies
can develop in such a way as to undermine confidence in the paradigm. An anomaly
will be regarded as particularly serious if it is seen as striking at the very
fundamentals of a paradigm and yet persistently resists attempts by the members
of the normal scientific community to remove it.[17] The length of time that
an anomaly resists attempts to remove it will also bear on its seriousness.
When anomalies come to be seen as
posing serious problems for a paradigm, a period of crisis sets in. Once a
paradigm has been weakened to such an extent that its proponents lose their
confidence in it, the time is ripe for revolution. The seriousness of a crisis
deepens when a rival paradigm makes its appearance. The new paradigm will be
very different and incompatible with the old one. Kuhn argues that there is
always a radical difference between the new and the old paradigm. Each paradigm
will regard the world as being made up of different kinds of things. This is
because the way scientists view a particular aspect of the world will be guided
by a paradigm in which they are working. Rival paradigms pose different kinds
of question and involve different and incompatible standards. Kuhn likened the
change of allegiance on the part of individual scientists from one paradigm to
an incompatible alternative to a “gestalt switch” or a “religious conversion”
of which none can claim superiority over the other.[18]
According to Kuhn, a scientific
revolution corresponds to the abandonment of one paradigm and the adoption of a
new one, not by an individual scientist only but by the relevant scientific
community as a whole.[19] When this occurs, a
“paradigm shift” is said to take place. In Kuhn’s view, when a revolution
occurs the old paradigm is replaced wholesale.[20] The new paradigm
gradually succeeds in attracting a group of followers who amplify the early
successes in the new paradigm that competes for allegiance with the old one. Paradigm
change is noncumulative because it involves change in scientific theories that
is not piecemeal but holistic.
5.0 The
Copernican Revolution
What is arguably the most famous
example of a revolution in scientific thought is the “Copernican revolution”. The Copernican Revolution was the paradigm shift from the geocentric Ptolemaic model of the heavens, which
postulated the Earth at the centre of the galaxy, to the heliocentric model with the Sun at the centre of the Solar System and the
Earth revolving round it with other planets.[21]
Even though, Copernicus initiated the revolution, he
certainly did not complete it. Individuals like Kepler, Galileo, Descartes and
others were motivated to adopt and work on the new paradigm by quite different
reasons, even when the Copernican paradigm was not yet fully developed, and
when it faced many unsolved problem. It was Isaac Newton who arguably finished
the Copernican revolution by providing a consistent physical explanation which
showed that the planets are kept in their orbits by the familiar force of gravity.
Kuhn’s
analysis of the Copernican revolution emphasized that, in its beginning, it did not
offer more accurate predictions of celestial events, such as planetary
positions, than the Ptolemaic system, but
instead, appealed to some practitioners based on a promise of better, simpler,
solutions that might be developed at some point in the future.
6.0 Incommensurability
Incommensurability is a term from mathematics which
means ‘lack of common measure’.[22] It was adopted by Kuhn
and Paul Feyrabend, both of whom argued that successive scientific theories are
often incommensurable with each other in the sense that there is no neutral way
of comparing their merits. The new paradigm cannot be proven or disproven by
the rules of the old paradigm and vice versa.[23] The paradigm shift does not merely involve the revision of an individual
theory, it changes the way terminology is defined, how the scientists in that
field view their subject, and, perhaps most significantly, what questions are
regarded as valid, and what rules are used to determine the truth of a
particular theory. The new theories were not, as the scientists had previously
thought, just extensions of old theories, but were instead completely new world
views.
Kuhn argues that there is
no higher standard for comparing theories than the assent of the relevant
community, and that the choice between competing paradigms proves to be a
choice between incompatible modes of community life.[24] He compares scientific
revolution to political revolution because just as there is no legal way to
establish which of the two competing factions in a political revolution should
be ruler, there is no rational way to settle which of the two competing
paradigms in a scientific revolution should be accepted. Hence, any tool
to be used by verificationists will
be inadequate for the task of deciding between conflicting theories, since
it will belong to the very paradigms they seek to compare.[25]
Similarly, observations that are intended to falsify a
statement will fall under one of the paradigms they are supposed to help
compare, and will therefore also be inadequate for the task. Many people have
used Kuhn’s arguments to support what philosophers call relativism about
scientific knowledge, which is the view that the ‘truths’ of scientific
theories are determined in whole or part by social forces.[26]
7.0 How Kuhn’s View of Scientific Progress
Differs from Traditional View
As mentioned above, Kuhn challenged
and rejected the seven views held by traditional philosophers of science on the
progressive nature of science. On the first view, he argued that the history of
science does not consist in the steady accumulation of knowledge, but often
involves the wholesale abandonment of past theories. This is because a
revolution scientist has a new way of looking at things and solving problems. [27] Kuhn
rejects the second view by arguing that theory-testing is not as
straightforward as implied because, when experiment conflicts with scientific
theory, logic alone does not tell us which of the components of the theoretical
system is at fault. Although observation and experience constrain scientific
beliefs, they do not singly determine them. Kuhn refutes the third, fourth and
sixth views by arguing that the evaluation of theories depends on local
historical circumstances, and his analysis of the relationship between theory
and observation suggests that theories infect data to such an extent that no
way of gathering of observations can ever be theory neutral and objective.
Hence, the degree of confirmation an experiment gives to a hypothesis is not
objective, and there is no single logic of theory testing that can be used to
determine which theory is most justified by the evidence. He thinks, instead,
that the value of scientist help determine, not just how individual scientists
develop new theories, but also which theories the scientific community as a
whole regards as justified. For instance, Einstein (a realist) never accepted
quantum mechanics (product of instrumentalism), while many other scientists did,
and the dispute between them is not about the empirical evidence in support of
the theory, but about what is to be valued in scientific theories. Kuhn points
out that psychological and sociological factors play a vital role in
determining which paradigm a scientist adopts or rejects.[28]
Kuhn’s argument against the fifth
view is that the same sorts of methods and reasons that lead to scientific
knowledge can also be used to produce other belief systems. His argument
against the seventh view which says that scientific term have fixed meaning is
that theories within different paradigms are incommensurable, in the sense that
the terms and concepts of scientific theories in different paradigms are not
mutually intertranslatable; this is called meaning incommensurability.
Kuhn assumes that scientific terms get their meaning from their position in the
structure of a whole theory. For example, ‘mass’ in Newtonian theory means
something different from ‘mass’ in Einstein’s relativity theory.[29]
8.0 Progress
Through Revolution
According to Kuhn, there is progress
in science when there are revolutions rather than the cumulative progress
characteristic of inductivist accounts of science.[30] Since he considered problem solving to be a central element of science,
Kuhn saw that for a new candidate for paradigm to be accepted by a scientific
community, “First, the new candidate must seem to resolve some outstanding and
generally recognized problem that can be met in no other way. Second, the new
paradigm must promise to preserve a relatively large part of the concrete
problem solving activity that has accrued to science through its predecessors”.[31] And Kuhn maintained
that the new paradigm must also solve more problems than its predecessor, which
therefore entailed that the number of newly solved problems must be greater
than those solved in the old paradigm.
9.0 Rationality, Relativism and
Realism
While the rationalist asserts that there is a single,
timeless, universal criterion with reference to which the relative merits of
rival theories are to be assessed, the relativist on the other hand denies that
there is a universal standard of rationality with respect to which one theory
can be judged better than another. What counts as better or worse with respect
to scientific theories will vary from individual to individual or from
community to community.[32] It is important to note
that one of the commonest charges directed against Kuhn is that he is a
relativist. In this way, Kuhn has been perceived as undermining the notion of
scientific truth and even of an objective reality. Hence, there are some people
who argue not that scientific knowledge is relative, bur that reality itself is
socially constructed[33]. This kind of relativism
is believed to be a kind of threat to realism and rationality. Before Kuhn’s
work it was common for philosophers to believe that what a particular
scientific term, say ‘atom’, refers to is determined by what the theory says
about atoms. If this is right, then different theories about ‘atoms’, which say
different things about them, will actually refer to different things. This is
called reference incommensurability, and it is bad news for
realism, for it suggests that different theories about ‘electrons’ are actually
all about different things, and hence there is no reason to believe that
science has made progress in understanding the underlying nature of things.[34] This seems to imply that
there is no one way the world is, but that rather the world we live in is an
artefact of our theories about it. Indeed, Kuhn says that ‘when paradigms
change the world changes with them and the different languages of different
theories correspond to the different worlds. Consequently, we cannot say that
Copernicus discovered that Ptolemy and earlier philosophers were wrong to think
that the Earth revolves around the Sun, because Copernicus’ Earth is literally
a different object from Ptolemy’s.[35]
Kuhn’s
work has been viewed by postmodern thinkers
as demonstrating that scientific knowledge is dependent on the culture and
historical circumstances of groups of scientists rather than on their adherence
to a specific, definable method. His work has also been regarded as blurring the demarcation between scientific and non-scientific
enterprises, because it describes the mechanism of scientific progress without
invoking any idealized scientific method that
is capable of distinguishing science from non-science.
Imre Lakatos criticized Kuhn for treating
revolutionary episodes as instances of “mystical conversion”. According to him,
Kuhn has portrayed the history of science as an irrational succession of
periods of rationality. Lakatos maintained that unless a rational
reconstruction of theory replacement can be given, the interpretation of
scientific change must be left to historians and psychologists.[36] Popper had produced a
rational reconstruction, according to which scientific progress is a sequence
of conjectures and attempted refutations. Lakatos sought to improve upon this
reconstruction. In particular, he urged that the basic unit for appraisal
should be “research programmes” rather than individual theories. According to
Lakatos, a research programme consists of methodological rules: some tell us
what paths of research to avoid (negative heuristic) and others what paths to
pursue (positive heuristic). [37]
Larry Lauden on the other hand, opines that progress
is achieved within a domain when successive theories display increasing
problem-solving effectiveness. Laudan sought to invert the logicist view of the
relationship between rationality and progress. The logicist view is that
development or progresses in science are to be judged by an appeal to a
standard of rationality. Laudan’s position, by contrast, is that those
developments which are progressive, that is which increase problem-solving
effectiveness qualify as rational.[38]
Conclusion
The manner in which
science progresses has remained a controversial issue among philosophers of
science like Popper, logical empiricists and Kuhn. While Popper and other
traditional philosophers of science held that an accumulation or increase in
knowledge or truth-likeness of a scientific theory is the indicator for a
progressive science, Kuhn on the other hand opines that there can only be progress
in science when scientific revolutions occur. He identifies three phases
involved in a scientific revolution: the pre-science
phase, the normal science phase which
is governed by a new paradigm. If the paradigm in a normal science encounters
an anomaly which is hard to resolve but rather accumulates to a crisis, a new
paradigm might be adopted by the scientific community, and this is the scientific revolution phase. The new
paradigm according to Kuhn will be incompatible with the old one and contrary
to traditional account. Nearly everyone rejected Kuhnian claims of
incommensurability because there was the outrage about its implications for
relativism, rationality, objectivity, and progress towards growth.
Bibliography
Books
Bird, Alexander. What is Scientific Progress? Oxford:
Blackwell Publishing, inc., 2007.
Chalmers, A. F. What is
This Thing Called Science? Buckingham: Open Uni. Press, 1990.
Dilworth, Craig. Scientific Progress. Netherlands: Springer
Publisher, 2007.
Kuhn, Thomas. The Structure of Scientific Revolutions. Chicago: Uni. Of Chicago Press,
1970.
Ladyman, James. Understanding Philosophy of Science. New
York: Routledge Publisher, 2002.
Loose,
John. A Historical Introduction to the
Philosophy of Science. New York: Oxford Uni. Press, 2001.
Journal
Weinberg,
S. “The Revolution that Didn’t Happen” The
New York Review of Books, (1998), pp. 48-52
Internet Source
Niiniluoto, Ilkka (2011).
“Scientific Progress”, The Stanford
Encyclopedia of Philosophy. http://plato.stanford.edu/archives/sum2011/entries/scientific-progress/ (4th
April 2013).
[1] Cf. A. F. Chalmers, What is This Thing Called Science?
(Buckingham: Open Uni. Press, 1990), p. 89.
[2] Cf. Alexander Bird, What is Scientific Progress? (Oxford: Blackwell Publishing, inc.,
2007), p. 64.
[3] Cf. Craig Dilworth, Scientific Progress (Netherlands:
Springer Publisher, 2007), p. 19.
[4] Cf. Ilkka Niiniluoto (2011),
“Scientific Progress”, The Stanford
Encyclopedia of Philosophy, http://plato.stanford.edu/archives/sum2011/entries/scientific-progress/ (4th April 2013).
[5] Cf. Alexander Bird, loc. cit.
[6] Cf. James Ladyman, Understanding Philosophy of Science (New
York: Routledge Publisher, 2002), p. 96.
[8] Cf. James Ladyman, op. cit., p. 98.
[10] Cf. Ibid. p. 99.
[11] Cf. A. F. Chalmers, op. cit., pp. 90-91.
[12] Cf. Ibid., p. 91.
[13] Ibid.
[14] James Ladyman, op. cit., p. 100
[15] Cf. Ibid., p. 101.
[17] Ibid.
[18] Ibid., p. 96.
[19] Ibid,. p. 97.
[20] Cf. James Ladyman, op. cit., p. 102.
[21] Cf. Ibid., p. 105.
[22] James Ladyman, op. cit., p. 115.
[23] Cf. Thomas Kuhn, The Structure of Scientific Revolutions
(Chicago: Uni. Of Chicago Press, 1970), p. 148.
[24] Cf. Ibid., p. 94
[25] Cf. A. F. Chalmers, op. cit., p. 94.
[27] Cf. Ibid., p. 97.
[30] Cf. A. F. Chalmers, op. cit., p. 99.
[31] Cf. Thomas Kuhn, op. cit., p. 168.
[33] Cf. James Ladyman, op. cit., p. 118.
[36] John Loose, A Historical Introduction to the Philosophy of Science (New York:
Oxford Uni. Press, 2001), p. 203.
[37] Cf. Ibid.
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