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

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 natural selection, unguided evolution based upon a species ability to reproduce itself, rather than some goal-oriented process. It was this idea that caused his theory to be treated with skepticism by so many, but in many respects it was just another stepping stone towards better understanding of the biological process. If Darwin had presented his idea to a group of cynical existentialists, they probably would have merely yawned. This suggests a wholly different critique of Kuhn, his utter disregard for the social and political climate within which science must operate, but that is a subject for another paper.

The early life sciences in the early nineteenth century explored the idea of evolution (in particular, Lamarck proposed a differing sort of evolution that relied upon vague ideas of teleological change), and the diversification of species. Darwin and Wallace's work explained how randomly mutating traits, inherited by successive generations that managed to reproduce, resulted in diversification and non-teleological evolution. Gregor Mendel explained how traits were inherited, although not why. R. A. Fisher explained how genetics and natural selection were partners and not competing theories. Watson and Crick unraveled the double helix, explaining Mendel's why. Eldredge and Gould explained how species were generally stable populations, but that isolated populations could rapidly diversify, thus solving a number of problems with the fossil record. Other scientists have shown natural selection acting in the wild in a time frame within a human lifespan, explored our own convoluted evolutionary history (in and out of Africa again, etc.), decoded the human genome, or done any number of things which both confirm evolution and widen our awareness of its applications.

Any number of these things could be described as a Kuhnian “paradigm shift” in that they broaden the understanding of the scientific community, solve certain anomalies, and provide more puzzles for future research. But none of them contradicted the fundamentals of Darwin's theory. And most of them prompted the same reaction that T. H. Huxley had when he first read The Origin of Species, “How extremely stupid not to have thought of that!” To be sure, Kuhn's view of scientific behavior is not completely absent from the history of biology. Any group of people has the capacity for groupthink and most of us see what we expect to see when we examine something. The above post-Darwinian biologists found Darwinian answers to problems when they examined those problems through a Darwinian mental lens. But their discoveries seem to be mostly “normal science”, with only Fisher prompted by a “crisis”. And yet if one is to say that there have been any paradigm shifts in biology other than Darwin/Wallace, almost all of the above would seem to fit. There is a better theory to explain the history of biological development, actually all intellectual development – and it is an extension of the modern neo-Darwinian synthesis.

Extend the Phenotype, Meet the Meme.

In normal discussions regarding genetics and biology, organisms are described as having genotypes and phenotypes. Encoded within my DNA is a string of chemicals that determine eye color; they manifest themselves in a phenotype usually described as hazel. This is a fairly easy concept to grasp, as an individual considers the lines of code that determine (along with environment) most of our physical characteristics. What is harder to grasp, but no less true, is that our brain is a phenotype, and it contains within a chemical soup, a morass of electrical impulses that we perceive as ideas. Our ability to recognize things, to remember them, to critically evaluate them, are all expressions of our DNA. The ideas we have are interactions between our phenotypical reason and our environment.

Richard Dawkins put forth the proposition in The Selfish Gene that the ideas humans have behave in a manner similar to genes, with regards to their propagation throughout a population. He coined the term “meme” to explain this phenomenon. Kuhn comes very close to this idea when he describes science as analogous to Darwinian evolution – in that it has no teleological goal. But memes, unlike paradigms, are atomized (like genes). As we have seen, scientific frameworks are not monolithic paradigms like Kuhn describes, but rather convenient collections of ideas that look like overarching structures. Rather than completely overturning Descartes, Newton subtracted some bad ideas (plenum), added some good ideas (gravity) and created a new collection of memes that were accepted by his contemporaries and created a new framework for the physical sciences. Anything that can be called science includes a crucial meme first espoused in the western world (as far as we can tell) by Thales of Miletus – that the world has natural explanations (this is a crucial separation between the first philosophers and Greek Mythology, as typified by Hesiod's Theogyny). Viewed in this way, science can be seen to be additive, and yet include everyone that we would like to consider a scientist, from Aristotle to Hawking.

Kuhn’s view of paradigms does seem to accurately reflect some scientific behavior, and it is not difficult to see where “paradigms” might fit into a memetic account of intellectual development – just as genes express themselves in individuals, and memes express themselves in complex ideas – individuals comprise species, and complex sets of memetic propositions can be seen to comprise paradigms. Kuhn describes a process of paradigmatic evolution analogous to punctuated equilibrium in biological speciation. New “species” of thought (what Kuhn calls paradigms) tend to arise outside the stable centers of scientific thought, but then propagate and replace their predecessors when they show they are able to better survive in the scientific environment (solve more puzzles).

Science can also be seen to be progressive, although Kuhn does not disagree with the idea of a progressive science as much as some claim:

Later scientific theories are better than earlier ones for solving puzzles in the often quite different environments to which they are applied. That is not a relativist's position, and it displays the sense in which I am a convinced believer in scientific progress. (Kuhn, 206)
What is key here is recognizing the environment of which Kuhn speaks. In biological evolution, the environment is a host of factors for each organism – every other organism in the shared environment, and natural events. The environment within which scientific memes propagate is somewhat dependent on the natural world (insofar as the business of science is in interacting with it) but the puzzles of science are determined by humans – either colleagues sharing memes or the public at large availing itself of scientific discoveries. In this sense, scientific progress is not only possible, but it is the most successful enterprise in human history.

1. Paul is dead.

2. Although I don't have space for it in this paper, this idea can help resolve the Aristotle dilemma that seems to be the “first mover” for Kuhn's ideas. Namely, was Aristotle science? The earliest modern scientists had battled Aristotle's science until the consensus was that Aristotle was either “Not science” or “Bad science”. Kuhn argues that he was “Different science”. But given his continuing relevance (on rare actors such as Newton and Heisenberg), I would argue that he was “Early science” -- which is by definition (in a progressive view of history) both different and largely wrong, but still occasionally relevant.