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Officer and Drake succeeded neither in their effort to falsify impact by showing that the K-T event was not instantaneous (arguments 1 a and lb) nor in their attempt to discredit the evidence for impact (argument 2). In the process, though, scientists learned a great deal, especially about the geochemistry of iridium. Certainly the efforts of the doubters failed to discourage the proponents, who were growing in number. But on the other hand, those who supported the theory were equally unable to sway its firmest opponents. In fact, only a vanishingly small number are on record as ever having changed their minds on the Alvarez theory. One need read only a fraction of the vast literature on impact to predict with near certainty which side a given author will take in all subsequent papers: the same as in previous ones. Glen notes that he has "found neither in planetary geology nor in impacting studies anyone who ever wavered from the impact-as-extinction-cause component of the hypothesis, nor in vertebrate paleontology anyone who converted to embrace it."48 Michael Rampino of New York University and NASA; paleontologists Leo Hickey and Kirk Johnson of the Denver Museum of Natural History; and Peter Ward of the University of Washington, plus a handful of others, are exceptions, but they merely prove the rule. Some of the reluctance to switch sides is undoubtedly due to honest convictions firmly held, but some also results from the unwillingness of scientists, being human, to admit in public that they were wrong. And the role of tenacious skeptic, adhering faithfully to the old ways that have served so well for so long, can be a proud one. Even if eventually proved wrong, one fought the good fight and can hold one's head high. The trick is not to fight too long, or unfairly.

The critics of the impact theory next turned to argument 3: to replace the Alvarez theory by showing that another process—one as familiar to geologists as an old shoe—explains the evidence equally well and obviates the need for a deus ex machina. If they could not convince the pro-impactors of the error of their ways, at least the anti-impactors could present a persuasive case that would shore up support among those who had not yet made up their minds. The Alvarez theory would then eventually be discarded in that large dustbin of discredited theories.

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