Paradigms Lost and Paradigms Found: Examples of Science Extraordinary and Science Pathological—And How To Tell the Difference**

One of the most interesting challenges a practicing scientist faces is explaining to a nonscientist how science works and why scientists appear to have a way of knowing that, while not perfect, their discoveries seem to be the best that the human mind has been able to come up with. Scientists, in general, understand the tentative nature of the scientific process and that all conclusions are provisional, at least in principle. Nevertheless, in their everyday activities, scientists often behave as if they are dealing with a set of atruthso. This behavior is supported by the manner in which science confidently produces a seemingly unending series of stunning predictions and verifications, which often move rapidly into important technological applications, making the explanatory challenge more difficult. How can one be so sure about what one aknowso and, at the same time, avoid the arrogance of a know-it-all and the pitfalls of intellectual hubris? In this context, another challenge is to explain how science handles extraordinary claims. How can a scientist tell whether a remarkable idea or experimental observation would lead to the Nobel Prize, which is awarded for science that changes the way that scientists think and knowÐor would lead to the IgNobel Prize, awarded to pathological science that epitomizes the way the scientific process should not work? Throughout the history of science, the distinction between revolutionary science and pathological science has not always been so clear. What is the objective scientific process by which one distinguishes genius from nonsense? Both extremes of the scientific spectrum are characterized by a common trait: The ability of the scientist (or a community of scientists) to athink outside the boxo. But what is this box of which they must be outside? I would identify it as the paradigm, the concept popularized by Thomas Kuhn in The Nature of Scientific Revolutions.[1] Science makes quantum jumps when a paradigm shifts but an intricate and complex process with both scientific and sociological components is required to confirm that an extraordinary claim is revolutionaryÐthe content of true paradigm shifts±and separate it from those that are eventually shown to be pathological, destined for the dustbin of scientific history. For example, during the past century Max Planck published some mathematical computations intended to describe an apparent anomaly in the classical theory of light, which, at the time, was believed to be an unshakable paradigm. The anomaly was termed the aultraviolet catastropheo, which gives some idea of how severely the anomaly disturbed the scientific community! Planck made the extraordinary suggestion that if light were aquantizedo and consisted of bits of energy rather than a continuum of energy, which was the paradigm of the classical theory of light, the anomaly would disappear. At the time (and to some still) this appeared to be a preposterous suggestion, contrary to all known experience and a threat to the reigning paradigm of the classical theory of light. Yet a few years after the paper was published, Einstein connected Planck s suggestion to another anomaly involving the way that light causes electrons to be ejected from a metal (the basis of the photoelectric effect, which operates the aelectric eyeo of security doors everywhere). The interpretation of the photoelectric effect in quantum terms led to Einstein s Nobel Prize in 1921. For the next several decades the physics community endured a battle royal, with the ideas of quantum mechanics emerging triumphant, if still resistant to explanation in terms of ordinary experience. The emergence of the paradigm of quantum chemistry warns and teaches us that, no matter how bizarre a scientific claim may be or how remote from ordinary experience, it can still be accepted and used by the scientific community and even rapidly applied to technological uses! But what of the many remarkable claims that have been proposed, debated, and then dismissed by the scientific community as pathological? How was each decision made and how do we know the decision was correct? Are there any rules scientists can follow to minimize the probability of falling into the trap of promoting pathological science?