(posted on my blog: davenichols.net)

Thomas Kuhn's foundational work The Structure of Scientific Revolutions lays out the concept of paradigm shifts as fundamental to the history of science. While the book is dense at times, and certainly scholarly-technical in many places, Structure still contains an enjoyable read for anyone with an interest in the ways in which significant changes occur in scientific theories.

Kuhn's argument concentrates on shifts in fundamental concepts in the fields of astronomy and physics, as well as a few other areas. He describes how the prevaling paradigm provides a set of facts and instruments which enable further progress in the field while still leaving holes in need of work. Demonstrating that paradigm shifts occur only after a crisis in the field, Kuhn argues that such crises predict a fundament shift in the underlying tenats of the paradigm. While these paradigm shifts can certainly be tremendously important and change many of the basic assumptions, Kuhn makes clear that these changes are not immediate and take place, typically, over decades of work and debate, and at times, are hindered by popular adherents to the old paradigm.

Structure is probably not a book for most popular science readers, but for anyone who is enthusiastic about the history of science, there are few books which offer the sort of discussion available here. Kuhn's look at the nature of paradigm shifts, despite being decades old, still offers a profound and engaging argument for the processes behind the shifting descriptions of the natural world. Four stars, but recommended only to those who really enjoy history of science and epistemological arguments. ( )

A rebellion against science is running rampant in the West, causing such oddities as the cult of Global Warming. Here we can focus on one of the most important fomenters of this rebellion: Thomas Kuhn (1922-1996), author of the enormously influential "Structure of Scientific Revolutions."

Kuhn rejects the traditional view that science is a linear accretion of knowledge. In the traditional view, scientists build on the corpus that preceded them; through experiment and observation, they add a new fact here and a new discovery there, refining and adjusting the inherited learning. Slowly but surely, knowledge advances, and we modify the textbooks as we go.

Wrong, says Kuhn. Science in any given era is ruled by a paradigm, an over-arching theory that answers the big questions, and determines the bounds and the context within which everyday research takes place. Kuhn calls this everyday research "normal science," and its purpose is to flesh out and confirm the predictions of the paradigm.

At a certain point in the life of the paradigm, anomalies begin to appear. At first they are rationalized, as the paradigm is stretched and patched up to account for them. But eventually the anomalies become too glaring. Someone then comes along and proposes a bold new paradigm that completely replaces the old one. For example, Einstein's theory of relativity supplanting the former Newtonian system. Once the skeptics are defeated and the new paradigm is universally accepted, normal science resumes, but exclusively within the framework of the new paradigm.

In Kuhn's words:

"Sometimes a normal problem, one that ought to be solvable by known rules and procedures, resists the reiterated onslaught of the ablest members of the group within whose competence it falls. On other occasions a piece of equipment designed and constructed for the purpose of normal research fails to perform in the anticipated manner, revealing an anomaly that cannot, despite repeated effort, be aligned with professional expectation. In these and other ways besides, normal science repeatedly goes astray. And when it does--when, that is, the profession can no longer evade anomalies that subvert the existing tradition of scientific practice--then begin the extraordinary investigations that lead the profession at last to a new set of commitments, a new basis for the practice of science. The extraordinary episodes in which that shift of professional commitments occurs are the ones known in this essay as scientific revolutions."

At this juncture, I find myself somewhat in sympathy with Kuhn. One can think of several cases that seem to correspond to this process, a prominent one being Darwin's theory of evolution. It was certainly revolutionary, and "normal science" has busied itself with filling out the theory and--more recently--with wildly bailing out the sinking ship. One can imagine a new scientific paradigm emerging, causing Darwin to be relegated entirely to the history books.

The problem begins when Kuhn goes beyond merely illuminating the great revolutions that have occurred in scientific thought. These revolutions, for him, completely supplant the previous view; in fact, they create a new truth. There is no such thing as an objective, empirically verifiable fact. The only thing that can be verified is a given phenomenon in relation to the ruling paradigm.

In the exposition of this argument, Kuhn reveals his relativistic hand by wading in the muddy waters of experimental psychology, which showed radical shifts in perception based on the beliefs and expectations of the test subject:

"An experimental subject who puts on goggles fitted with inverting lenses initially sees the entire world upside down. At the start his perceptual apparatus functions as it had been trained to function in the absence of the goggles, and the result is extreme disorientation, an acute personal crisis. But after the subject has begun to learn to deal with his new world, his entire visual field flips over, usually after an intervening period in which vision is simply confused. Thereafter, objects are again seen as they had been before the goggles were put on. The assimilation of a previously anomalous visual field has reacted upon and changed the field itself. Literally as well as metaphorically, the man accustomed to inverting lenses has undergone a revolutionary transformation of vision."

These "revolutionary transformations of vision," says Kuhn, are equally applicable to the world of science:

"After a revolution, scientists are responding to a different world. It is as elementary prototypes for these transformations of the scientist's world that the familiar demonstrations of a switch in visual gestalt prove so suggestive. What were ducks in the scientist's world before the revolution are rabbits afterwards...Transformations like these, though usually more gradual and almost always irreversible, are common concomitants of scientific training. Looking at a contour map, the student sees lines on paper, the cartographer a picture of a terrain. Looking at a bubble-chamber photograph, the student sees confused and broken lines, the physicist a record of familiar subnuclear events."

As an exercise, let us apply Kuhn's method to Kuhn himself. We begin the exercise by saying that for thousands of years, at least since Aristotle, the reigning epistemological paradigm was that science is based on objective, verifiable facts. But more and more anomalies were found; modern thinkers noticed that the ideas of different individuals, groups, and nations are dependent upon a set of received values and beliefs. Thus who is to say which of the systems represents the truth? Along comes Kuhn and applies this modern relativistic approach to the last great bastion of objective truth: science itself.

Now, continuing our Kuhnian analysis of Kuhn: This paradigm, in its numerous permutations, has been in vogue for quite some time, going back at least to Hegel. Even looking at Kuhn alone, it is now nearly half a century since the publication of "The Structure of Scientific Revolutions." Anomalies are accumulating, and we begin to realize that relativism is...well...relative. Kuhn's theory is merely one more paradigm that inevitably will be replaced. Are not relativism and its derivatives (such as deconstructionism and multiculturalism) dependent upon a received set of values and beliefs, just like any other theory?

Thus the paradox of relativism: If everything is relative, and there are no real "truths," then we have no reason to accept relativism itself as more valid and "true" than anything else. It can be deconstructed and thrown out like any other notion.

Like its ideological cousin, Marxism, Kuhnian relativism refuses to admit the existence of a world, with its laws, its nature, and its continuity. It refuses to admit that we and Aristotle are looking at the same rock. Certainly, our interpretations differ, but the rock remains the same, notwithstanding some gestalt hocus-pocus that tricks us into seeing the rock upside-down.

Kuhn's remark that ducks become rabbits as a result of a scientific revolution brings to mind the following statement by Aristotle (in "The Metaphysics") on the intellectual short-circuit that occurs in philosophical relativism:

"If all contradictions are true at the same time of the same thing, palpably all things will then be one. For if it is possible either to affirm or to deny anything of everything, the same thing will be a ship and a wall and a man, as it must be for those who repeat the theory of [the relativist] Protagoras. Then if anyone thinks that a man is not a ship, undoubtedly he is not a ship. But, in the same way, he is a ship, if the contrary is true....I mean that if it is true to say that a man is not a man, then clearly it is also true that he is a ship and not a ship....Then all things will be one, as we said before, and the same thing will be man and God and ship and their opposites. For if we can make all these assertions of everything, there will be no difference between any one thing and any other...

"And if all men are equally wrong and right, a person like that can neither speak nor tell us anything, for he is saying at the same time both "yes" and "no." And if he has no opinion but both thinks and does not think together, how is he different than a vegetable? So it is very evident that no one, neither those who profess this theory nor any others, really abide by it....When he wants and looks for a drink of water or a man to see, he does not go looking for everything and taking them all to be the same; and yet he should, if the same thing were equally a man and not a man." ( )

A brilliant book, and one that has changed the way in which we talk and think about ideas and disciplines. But I've reread it recently, and found it had not aged well; I really don't like it at all---which in no way diminishes the importance of reading it, but its flaws are more visible now than they once were, perhaps.
Karl Popper somewhere draws a distinction between traditionalism and rationalism (though this sense of rationalism includes classical rationalists and empiricists both). Traditionalists believe that the burden of the argument always rests on those who propose a change from The Way Things Are, and rationalists (of Popper's sort) think that that way of valuing things is reprehensible. Kuhn is a Traditionalist! Who would have thought it. And he has built a historicist philosophy of science to justify his Burkean tendencies.
But if you haven't read this book, put down whatever you're reading now, and read it.

em português

I hated this book. It contains some really good ideas, which are totally worth discussing, but the whole thing is so much wordier and denser than it needs to be (this, coming from me!); seriously, the ideas put forth in this 200-page monstrosity would have been better shared in a 5-10 page article. ( )