Scientific Progression and Change (some philosophy of science-type rambling)

Preliminary statements: Although the idea of "science" undergoing a change in theory (as though it were a person going through stages of physical development) may strike some as strange, it is not inappropriate. Science, taken as a cultural entity or an intellectual project, can be seen as something unified. As trends come and go within the scientific community, the face of science itself changes. Consider the way in which we view science today, compared with the way science was received in the time of Galileo, and you may be able to see what I mean. In this sense, then, we can look at how science undergoes changes of theory (which in turn changes the perceived nature of science, notwithstanding its basic propositions of discovery and truth-finding).

The basis for a change of theory in science seems to lie in the appearance of sufficient anomalous information to make a theory seem plausible. The standard view of science says that scientific theories are arrived at by making observations of natural phenomena, figuring out what "facts" those phenomena represent, and then developing hypotheses based on those "facts". Depending on what school of thought you identify with, your scientific project then proceeds based on the confirmation or falsification of your theory (which seems to me to be essentially the same thing; if your theory is not meeting up with supporting evidence, it is probably either stagnating or being proven wrong, no matter what name you put on your method of doing science). Carl Hempel, for example, adheres to the received view of science as a progressive endeavor in which one observes phenomena, derives universal rules out of those observations and then looks for observable, testable facts. As a positivist, Hempel emphasizes the importance of scientific method; it will always be logical and will always follow one of two routes. These two routes are the deductive method, which starts investigations from a universal rule, and the inductive method, which starts with observations. The problem with induction is that it is hard to move from your observations to solid universal rules, because there are so many other "facts" running on a tangent with your "facts" that it is impossible to properly observe everything that could be of significance to what you are trying to do or figure out. Deciding on what is relevant is also a problem, because there are myriad reasons why this fact or that fact might be important; here we can see that objectivity in science becomes slightly doubtful, because there must be a choice made when deciding to pay attention to certain facts. It is fair to assume that the decision is not always made by flipping a coin.

Again, in this model, either confirmation or falsification is trump (depending on which way you look at it). Confirmation depends on the quantity of tests you run your theory through, the variety of tests you use, and whether or not your theory agrees with accepted doctrine. This does not entirely make sense, because if one of the requirements of confirmation is that your theory agrees with accepted theories, then it follows that scientists may only adopt theories that already agree with mainstream science just so they can proceed! When a theory does not meet these criteria, it is viewed as fruitless, and is then discarded. This also presents a problem, because if you are only looking for proof that your theory fits what has already a part of the scientific canon, then you would have a hard time actually finding out anything new. Instead, you would just be trying to support what everyone already thinks anyway! It appears that in the positivist perspective, theories do not change; they are only supported by accepted theories because they support accepted theories (or else they do not do the former, which means the latter is not even a possibility).

The falsificationist method is more progressive and logical. Instead of looking for support, the researcher attempts to disprove his or her theory. Anomalies are reason to call your project into doubt, and when enough anomalous information pops up, you theory has to be seriously reworked or thrown out. This brings to mind a sort of Hegelian dialectic (as it has been formulated - he did not actually use these terms) in which the thesis (proposed hypothesis) meets antitheses (anomalies) and out of that meeting a new thesis arises, and progress takes place. A change in theory as per this method occurs in cases of falsifying evidence presenting itself, which causes scientists to rethink their course of action. Sir Karl Popper, a proponent of falsificationism, says that this methodology is preferable to that of confirmation because you can "confirm" anything if you are performing poor science. W.O. Quine agrees, saying that any body of evidence can be used to support an innumerable amount of other theories. Falsification requires that a theory must meet a standard of reliability ; this is the improvement upon the confirmation methodology.

The problem with falsficationism is that what could be a productive theory (given time) is often unduly buried because of anomalies that could be put aside and worked out later on. Increased accuracy could lead to new discoveries in areas that would otherwise be brushed off and forgotten. For this reason, the falsificationist model is also not entirely useful.

Thomas Kuhn comes in here and looks at scientific method differently; changes in theory can and do occur because of reasons external to pure evidence and method. The way in which scientists were trained, their system of beliefs, and even their personal preferences all contribute to what gets supported and what gets dismissed. A scientist trained in a certain way is prone to put an emphasis on certain things and not notice other things. These modes of indoctrination are prevalent in periods of "normal science"; in such periods, says Kuhn, progress does not really take place. Instead, scientists engage in research focused on their on fields, problem solving and brushing up on existing theories.

Real change occurs when a when a new theory comes along that shakes up all the "normal" science. These are times of crisis in which progression finally occurs. First, numerous anomalies show up, which causes a crisis, and then a new perspective arises- this is a scientific revolution.

Shifts of theory in science always seem to be rooted in anomaly and uncertainty. The discovery of crisis-inducing evidence is what opens the opportunity for a new way of looking at things; it is through the difficulties of readjusting and rethinking scientific research that theories evolve and move in different directions.

How does Science undergo theory change? (That is, what do philosophers of science say about how science undergoes theory change...?)

There are a number of answers to the question, but the debate can really be split into two camps: the evolutionary model of science (illustrated by the Logical Positivists and Popper) and the revolutionary model of science (illustrated by Kuhn, and in some ways, by Feyerabend).

For the Positivists, we change theories when our theory is less highly confirmed then another competing theory. This confirmation depends upon:

i) The quality of tests used to confirm it

ii) The variety of tests used to confirm it

iii) Agreement with accepted theories

The third criterion (agreement with accepted theories) is applied simply to weed out the number of `crazy' theories so that science does not have to deal with every crackpot scheme that arises. Once a theory provides enough empirical data, however, the first two criteria take over, and confirmation depends upon testability. A theory must be testable to be confirmable. The problem with the idea of confirmatory tests (particularly with `crucial experiments' that decide instantly between theories) is that interpreting a test as confirmatory to a particular theory already constitutes a hypothesis about what counts as confirmation or not (one that needs to be itself confirmed, and so on). In addition to this objection, a supposedly refuted theory can always offer ad hoc defenses for itself. It seems that the three criteria above are not enough to describe all cases of theory change. Thus, the Logical Positivists introduced a fourth criterion

iv) Simplicity

Which means that when we are required to decide between two theories that are equally confirmed in all other respects, we should choose the simpler of the two. But here we run into the same sort of objections that we saw with the idea of testability. We have to decide what constitutes simplicity, and justify it, and so on.

Karl Popper, rather than rely on the notion of confirmation, provides us with the idea of falsification. He states that a change in scientific theory relies upon instances of falsification. He rejects the problems inherent in `confirmability' (a few of which are stated above) and says that we only change theories when we encounter a falsifying instance (an anomaly that the theory cannot explain). Popper says that we drop a theory and move on to a better one as soon as there is a falsifying instance.

This brings us to Kuhn. Kuhn believes that Popper is wrong and I concur. Historically there are innumerable instances where theories have encountered falsifying instances but moved on to become accepted. In fact, it seems that most new theories would be contradictory when they are first born. Galileo in particular contradicted almost every accepted physical principle of the time, yet his theory became widely accepted.

Rather than as a sequence of refuted theories, Kuhn sees science as a historical process that goes something like this:

...Normal Science --- Anomalies Building Up --- Crisis --- Revolution --- New Normal Science...

Kuhn thinks that though falsification or confirmation may be useful within normal science (within a single accepted paradigm) neither can explain scientific revolutions. Kuhn believes that a scientific revolution occurs when anomalies within a particular paradigm build up to such an extent that it becomes unworkable, and a new paradigm appears then a new process of normal science occurs. Notice that I said that a new paradigm appears and not refutes. This is because Kuhn sees rival paradigms as incommensurable, and the process of revolution as one paradigm dying off, rather than being `defeated' by its opposing paradigm.

So what criteria do we use to decide between theories? The answer is that there are no decisive rational criteria to decide between theories, because theory-choice is not simply a matter internal to science. To assume that theory choice was an entirely rational affair would be, for Kuhn, to assume that humans are entirely rational animals, which (as history shows us) is obviously false. Instead, people like Kuhn (and more vehemently, Feyerabend) think that we do allow external (social, economic, psychological, artistic, etc, etc) factors to affect theory choice. Examples of this abound in the history of science: the rhetoric/propaganda of Galileo, the discovery of the structure of DNA, the advent of quantum theory, etc, etc.

Personally, I think that the Feyerabendian picture of theory change is more realistic. It allows us to change our criteria based on the particular situation we are in. We are not limited by a nice little rationalist box, which limits our descriptive power greatly. Rather, Feyerabend allows us to describe any particular theory change based on its historical occurence. Rather than resorting to a given set of tools for every theory change, we create tools specifically for a particular description. Accepting Popper or the Logical Positivist's would mean either rejecting a good portion of `science' as non-scientific, or simply accepting our inability to describe it. But, if allow external factors to affect the course of science, we are able to describe a much, much larger portion of the history of science.

Keep in mind that these opinions on theory change are given by historians, philosophers and sociologists of science...

I have to admit it's getting better
A little better all the time
(It couldn't get any worse)¹

Is Thomas Kuhn's theory of Scientific Revolutions correct? Is the progress of science a gradual and additive enterprise? Or is it a series of extraordinary breakthroughs completely different from the “normal science” in between them? Answering this question in the negative is problematic. Although Kuhn's theory is intended to apply only to the sciences, one can draw parallels to other areas of human intellectual development. Anyone who would claim that intellectual development is a fundamentally additive process cannot, therefore, agree or disagree with Kuhn completely. One can imagine a conversation between intellectual historians:

A: Thomas Kuhn is wrong. Scientific Knowledge is additive.
B: All right then, what did he add?

The most fundamentally important addition Kuhn made was the emphasis he placed upon social aspects in scientific behavior. Scientific paradigms are not ethereal forms or mechanistic rules of conduct, but shared theories, rules, and values held by communities of individual scientists. Kuhn's view of scientific progress turns our attention to its human nature. And with our attention thus turned, we begin to see the uncertainty of the enterprise – the glorious mistakes, jealous rivalries, neurosis, and pure genius speculation. Science cannot be viewed as a sort of computer or pocket watch, wound up in the Renaissance and moving steadily forward since then. At the same time, Kuhn's observations and theories are limited, and do not seem to accurately describe the progression of all of the sciences. On pages 171-2 of The Structure of Scientific Revolutions, Kuhn explicitly endorses an analogous reading of his work, comparing scientific “progress” with biological “progress”, almost going so far as to suggest the scientific process as being Darwinian. Kuhn's mistake is that he did not go far enough. The relationship is not analogous – human intellectual progress, by virtue of it being done by humans, is biological in nature. Science is an extended phenotype of the human species. In one sense, in relationship to “the universe” or “being” or whatever else you may set up to be an objective observer, science has no purpose, no progression beyond being an amusing diversion that we little ape-creatures indulge in. But from a human perspective, science has a progressive character – and the result is our greater ability to explain and manipulate the world around us.

I don't trust Paradigms, they're shifty.

Kuhn's The Structure of Scientific Paradigms provides a description of science sharply at odds with previous notions regarding historical progress, but that was over forty years ago. Rather than being the daring innovation it once was, Kuhn's theories are now the closest thing to conventional wisdom in studies of the History of Science, and have been broadly applied to other disciplines. Our place, in the first decade of the twenty-first century, cannot be to resist his arguments, but to go beyond them.

Kuhn describes previous theories of scientific development as gradual and iterative – scientists proposing hypothesis based upon observational data, building experiments to test these hypothesis, discarding bad ideas, constructing theories out of good ideas, and then using these theories to propose new hypothesis. Lather, rinse, repeat. Kuhn partially agrees with this conception of science, calling it “normal science” working within an established “scientific paradigm”. For Kuhn, normal science is the act of solving puzzles, within an established framework of scientific thought. For example, the Copernican revolution established that the planets all revolved around the sun in uniform motion. This paradigm of thought was accepted (after much initial resistance) because it accurately predicted the solar year better than previous geocentric models. But the Copernican Heliocentric model was slightly off when predicting the orbits of the other planets around the sun, and it thus fell to normal science to bring known facts about the places of the planets in line with the Copernican theory. This is the normal function of science – basic puzzle solving, with no revolutionary changes. Indeed, normal science does not react well to revolutionary ideas, and the scientific community usually greets them with skepticism, if not outright hostility. Only after a significant amount of time and energy has been spent on debate does a scientific community accept a new paradigm en masse, with a theory going from controversial to common wisdom in the blink of an eye.

The previous example provides us with an immediate problem with Kuhn's theory. What sort of science was Kepler performing when solving the problem of planetary motion? Before he began his calculations, he had accepted the Copernican paradigm, but most others in the scientific community had not – it was his explanations of planetary motion that led to the paradigm's acceptance. Kepler's astronomical calculations certainly have the feel of normal science (from Kepler's perspective) and the feel of a paradigm shift (to people after him). Kuhn indicates that Kepler's discover of the planetary laws of motion is archetypical of a paradigm shift. Scientists who were working under the Copernican theory found anomalies that could not be explained sufficiently with the existing rules, this provoked a crisis of faith in the system, this crisis was solved with Kepler's new theory, and the resolution was of a new Copernican-Kepler paradigm that more accurately accounted for planetary motion. What is this new paradigm? While one can interpret it as a refutation of Copernicus, Kepler didn't seem to think so, viewing his theories as a refinement of the Copernican Theory. Refining theories is what normal science is supposed to do, according to Kuhn, and refined theories are not supposed to create new paradigms. Except for when they do.

Since Kuhn took great care to analyze the sociological and psychological backgrounds of scientists, I do not think he would begrudge me for attempting to analyze his. He readily admitted that the examples drawn from in the book were from a few limited fields of study that he knew well. One might point out that in the history of science there are two major scientific revolutions that follow Kuhn's description of paradigm shifts almost exactly – those of Newton and Einstein. It should not be ignored that Thomas Kuhn received his undergraduate degree in physics. It is tempting to abandon these two cases and concentrate on murkier scientific progress, but some temptations are too strong not to resist.

Newton appears to us, in historical hindsight, to be a towering figure of genius, carving a new understanding of physics that stood unchallenged for two centuries. At a time when his contemporaries were engaged in explaining the actions of the universe only through matter and motion, he had the vision (perhaps inspired by his intense religiosity) to imagine forces, and the genius to create an entirely new branch of mathematics to explain them. Newton himself (in a letter to Robert Hooke) would disagree, “If I have been able to see farther, it was only because I stood on the shoulders of giants.” Comparing Newton's Principia Mathematica to Descartes' Principles of Material Things (an example of the prevailing mechanistic physics that existed before Newtonian physics) one is struck not by their differences, but the degree to which they agree. Newton's laws of motion are almost identical to Descartes'; there is an argument to be made that Newton merely revised mechanistic physics – a major revision, to be sure, but an additive one. Indeed, one can also see hints of Aristotle's physics in Newton's – he rehabilitated the lost idea that an object can have within it qualities that compel motion with no other object acting upon it (although Aristotle's causes of motion differ greatly from Newton's, they share the idea of elementary forces compelling action). Perhaps a measure of Newton's genius was that he still read Aristotle².

In Einstein we have another example of what a major paradigm shift looks like: a Swiss patent clerk working on the outskirts of a community ensconced within a paradigm provided revolutionary theories which were later proved to the satisfaction of the scientific community to such a degree as to inaugurate a new way of thinking about the universe itself. Indeed, his contemporaries were fond of suggesting that Einstein's papers from his “Miracle Year” advanced physics twenty years. And while Einstein was still busy arguing over the details of his theories, younger physicists quickly adopted them and created the study of quantum mechanics. Was it normal science to solve the puzzles created by Einstein? Or was it extraordinary science to create a new field of physics that even Einstein resisted at first?

Kuhn's view of science is compelling when one looks at a broad outline of the history of science, one can see a pattern of “normal science” and “extraordinary science” operating in tandem. When one looks closer, one sees more and more instances of “extraordinary science” and paradigm shifts operating within “normal science”. But we can also see long periods of “normal science”, with no obvious “extraordinary science” that nonetheless seem to have undergone a “paradigm shift” over a period of decades or centuries. Even in the archetypical scientific revolutions of Newton and Einstein, one gets the feeling that the science they do is characterized not by its nature, but by its speed. They are conspicuous because of the speed with which they reached conclusions that had eluded others – but the difference between “normal science” and “extraordinary science” seems to be one of degree, not of kind. And if Kuhn's view of science is supported most by the progress of physics, it doesn't seem to correlate at all to the biological sciences.

On the Origin of Theories

In trying to correlate Kuhn's theory to modern biology, the only really sensible analysis seems to be that before Darwin (and Wallace), biology existed in a pre-paradigmatic state driven by theology, metaphysics, vestigial Aristotelianism, and some stamp-collecting (i.e. species classification). After Darwin and Wallace published their theories, the scientific community fought it out, and afterwards Darwinian Evolution has served as the primary paradigm for all of the life sciences. Or in the words of Theodosius Dobzhansky, “Nothing in biology makes sense, except in the light of evolution.”

The problem with this reading of the history of biology is that it doesn't match up with historical reality – at least not in the same way that the history of physics or chemistry does. While Darwin and Wallace's theory maintained a place of prominence in biology through the end of the nineteenth century and early part of the twentieth century, it was not until R.A. Fisher synthesized natural selection (in the 1930s) with Gregor Mendel's re-discovered early genetic research that evolution became the dominant driving force in biology, occupying a place easily identifiable as a scientific paradigm. It was even later, with Gould and Eldredge's Punctuated Equilibrium that paleontologists and geologists came on board (in 1972, over a century after Darwin published The Origin of Species). This seems like an awfully long time for a paradigm to take effect, and also – each of the above authors was certainly writing within a Darwinian framework. There are problems on the other side of the historical timeline, as Kuhn himself notes:

When Darwin first published his theory of evolution by natural selection in 1859, what most bothered many professionals was neither the notion of species change nor the possible descent of man from apes. The evidence pointing to evolution, including the evolution of man, had been accumulating for decades, and the idea of evolution had been suggested and widely disseminated before. (Kuhn, 171)

Darwin's contribution was the idea of