Styles of Knowing: A New History of Science from Ancient Times to the Present

5. The Experimental Style II: The Skeptics and Their Opponents

72 The final greek PhilosoPher that Renaissance humanists reclaimed for the Western tradition was Sextus Empiricus. We do not know much about him; he lived around AD 180 and was a disciple of Pyrrhon, the great Skeptic of the ancient world. Sextus probably did not attract a great deal of notice during his life, since there were other philosophers with similar views. Coincidentally, however, he is the only radical Skeptic whose writings have survived. Before the rediscovery of Sextus, Diogenes Laërtius had provided some information on Pyrrhon, and Cicero was known to have advocated a much milder form of Skepticism. When Sextus became available in Latin translation for the first time in 1562, he immediately drew considerable attention. A century later, Pierre Bayle, the publisher of the Rotterdam -based philosophical review Nouvelles de la république des lettres, proclaimed Sextus the father of modern philosophy.1 How did Sextus achieve such renown more than fourteen centuries after his death? Skepticism was a frontal attack on the validity of the deductive style of thinking. If we survey the whole turbulent reception history of Skepticism in the sixteenth and seventeenth centuries, we can see that while it did not annihilate the truth claims of the deductive style, it did limit their scope dramatically. The domain of certain knowledge (scientia) again lost ground´ 5 The Experimental Style II The Skeptics and Their Opponents Life is a material and corporal motion, an action imperfect and irregular of its own proper essence . . . —Michel de Montaigne The Experimental Style II ´ 73 to knowledge that was plausible but fundamentally uncertain (opinio).2 In addition, Skepticism cleared the way for an exploratory, experimental style that was not tied to the deductive style of thinking; in other words, a less constrained experimental style than Galileo’s. Yet Skepticism won its first battles in the field of religion. That was also what made it useful; the rediscovery of Skepticism coincided with the rise of the Reformation. At first, Skepticism was mainly used to argue for tolerance, particularly by Desiderius Erasmus. Later, Protestants and Catholics began to use Skepticism to undermine each other’s positions, and it became a dangerous double-edged sword, a potential threat to public order. Descartes was the most formidable opponent of Skepticism, and his reasoning was both theological and scientific . Likewise, Galileo and Kepler wanted nothing to do with Skepticism. As adherents of the Copernican system, they could not support a philosophical view with a noncommittal approach to important questions. Sextus, like his teacher Pyrrhon, espoused an extreme and uncompromising strain of Skepticism. Descartes mounted a defense that was just as uncompromising, and ultimately untenable, but one of his contemporaries, Marin Mersenne, developed a moderate form of Skepticism that put aside the question of a theory’s ultimate truth, giving free rein to the method of experimental exploration. For Mersenne, good technique (along with the criterion of effectiveness derived from it) was the hallmark of good science. Radical Skepticism The Greek Skeptics opposed all other schools of philosophy, especially those of Plato, Aristotle, and the Stoics. They challenged the idea of certainty, rejected dogmas of all kinds, and distrusted sensory experience. Above all, they contested the syllogism, the gold standard of logical reasoning, as well as the claim that there is a criterion for determining which of two or more views is correct. A Skeptic would advise suspending judgment.3 Is Skepticism a negative dogmatism, then, based on the dogma that there are no dogmas? No, because it suspends judgment on this question too. This makes it a difficult position to maintain in a psychological sense; the Skeptic perceives no underlying regularity in the world, no firm footing. Sextus himself claimed that accepting this situation would bring peace and serenity, but the famous Skeptic Montaigne expressed feelings of agitation and anguish. Montaigne could not find peace, not even deep within himself , and that is striking because Calvin and Descartes described the inner self as the basis of certainty. Sextus would have said that Skepticism is also the best remedy for this type of agitation. Montaigne sought a balance, temporary if necessary, among the patterns of his life, without aspiring to universal solutions. In this respect, he and Descartes were polar opposites.4 74 ¨ The Experimental Style II The Skeptics’ arguments against the criterion of truth and the syllogism played a central role in sixteenth- and seventeenth-century debates on religion and science. Skeptics...