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Skepticism: Academic and Pyrrhonian


SKEPTICISM: ACADEMIC AND PYRRHONIAN. Skepticism dogged claimants to knowledge and truth throughout early modern Europe. In its most general sense it refers to uncertainty, doubt, disbelief, suspension of judgment, and rejection of claims to knowledge. It is characterized by its opposition to dogmatism, which means the holding of firm beliefs (from Greek dogmata ) about truth and reality. As a philosophical stance it is best understood as the outcome of two traditions in ancient Greek philosophy. Academic skepticism was attributed to Socrates and to Plato's successors at the Academy in Athens (fifth to second centuries b.c.e.), and Pyrrhonism was traced back to Pyrrho of Elis (c. 365275 b.c.e.).


Roman statesman and philosopher Marcus Tullius Cicero (10643 b.c.e.) is our chief source for Academic skepticism. In his Academica (45 b.c.e.) he reported on the teachings of Arcesilaus (315240 b.c.e.) and Carneades (214129 b.c.e.), who were heads of the Academy, and he claimed allegiance to the Academic school. St. Augustine's earliest extant work was entitled Contra Academicos (386 c.e.; Against the academics), and this polemic was an important source of knowledge about Academic skepticism.

Placing Socrates at the origins of skepticism turns on the argument that he only asked questions and did not teach positive doctrines. Plato and Aristotle strayed from the path when they claimed to know the truth. Arcesilaus gave renewed vigor to skepticism, arguing against the opinions of all men, as Cicero put it. But he also showed that skeptics could make choices by relying on the eulogon (the reasonable) in the absence of truth. Carneades, who was also a master of arguing on both sides of every issue, refined this into the standard of the pithanon (the credible). In Cicero's translation into Latin, this became probabile, which set the stage for the skeptics' claim to live by the probable in the absence of truth.

Cicero's Academica was read by some thinkers in the Middle Ages but does not seem to have had a major impact. It was first printed at Rome in 1471, and numerous commentaries and annotations followed. More than one hundred editions had been published by 1600.

One of the first to take Academic skepticism seriously was Dutch Humanist Desiderius Erasmus (1466?1536), who expressed admiration for the Academics in his Praise of Folly (1511), provoking opposition from Christian scholars like Philipp Melanchthon (14871560). Gianfrancesco Pico della Mirandola's Examen Vanitatis (1520) drew on both Cicero and Sextus Empiricus. Omer Talon emphasized the philosophical freedom from dogmatism of the Academics in his Academia of 1547, and Petrus Ramus praised their style and rhetoric in Ciceronianus of 1557. Both of these were attacked by Pierre Galland and Guy de Brués. Giulio Castellani defended Aristotelianism against Academic skepticism in Adversus . . . Ciceronis (1558), partly by showing empirically that disagreement was not as widespread as the skeptics claimed it was. Johannes Rosa published the most substantial early commentary on the Academica in German-speaking Europe in 1571, and Pedro de Valencia reconstructed Academic skepticism in his own Academica of 1596, showing that these ideas were available in Spain.

The publication of the works of Sextus Empiricus in the 1560s replaced Cicero's writings as the chief source of knowledge about ancient skepticism. In the following centuries most authors drew their inspiration from both sources to the extent that it is hard to speak of purely Academic skeptics after that point. One exception is David Hume (17111776), who has sometimes been called an Academic skeptic becauseamong other reasonsone of the characters in his Dialogues concerning Natural Religion (1779) takes the role of an Academic. There has also been scholarly debate about whether other individual early modern figures were Academic skeptics or Pyrrhonians, but in this period the two traditions were often run together, and few, if any, authors made a clear distinction between them.


Our chief source for ancient Pyrrhonism is the work of the Alexandrian Greek physician Sextus Empiricus (second century c.e.), including Outlines of Pyrrhonism and Against the Mathematicians. A few manuscripts of Latin translations of Sextus Empiricus existed in medieval collections, and more came from Byzantium in the mid-fifteenth century. Florentine religious reformer Girolamo Savonarola (14521498) used Sextus to combat pagan philosophy. But the printing press made for the most influential dissemination of these texts. Latin translations by Henri Estienne (Stephanus) (1562) and Gentian Hervet (1569) provided the stimulus for a widespread "skeptical crisis."

As Sextus explained it, skepticism was not a philosophy but rather a way of life in which one opposed all philosophical claims with equal opposite claims (equipollence). He laid out standard tropes or formula arguments which could be used against any certainty or truth and which he attributed to Greek philosophers Aenesidemus (first century b.c.e.[?]) and Agrippa (first century b.c.e.[?]). The result was that one would suspend judgment and then find oneself in ataraxia or tranquillity, no longer disturbed by philosophical disputes. One would live in accordance with the phenomena or appearances without taking a stand on the truth or reality behind them, and one would follow one's natural impulses as well as local customs and laws.

Michel de Montaigne (15331592) was the most influential of the early writers to draw on the writings of Sextus, in his Essais (15801595). In a long chapter entitled "Defense of Raymond Sebond," Montaigne retailed most of the skeptical tropes and all of the skeptical vocabulary from Sextus Empiricus. Here and in other essays he demolished any pretensions to human knowledge and argued both sides of almost every issue. And yet he never despaired; rather, he showed people how to live a happy life in the face of skepticism, which may explain why his writings were so popular.

Later philosophers often started from Montaigne. One who went far beyond in posing questions of skepticism was René Descartes (15961650). Without specific sources in the ancient materials, he set out to answer the skeptical idea that there could be an all-powerful malin genie or evil demon that controls our perceptions and reasoning and fools us about the world. His conclusion was that we know we exist because we can thinkthe famous "I think therefore I am." Pressed for an explanation as to why our perceptions of thinking could not be a deception, Descartes asserted that God would not allow such deception. Thus, religion is invoked to certify truth. Later skeptics would worry about a deceiving God.

Bishop Pierre Daniel Huet (16301721) and Huguenot refugee Pierre Bayle (16471706) have been described as the "master skeptics." Huet invoked Sextus Empiricus in great detail against Descartes and many other dogmatic philosophers in his Traité de la foiblesse de l'esprit humaine (1723; Tract on the weakness of the human mind). Bayle's massive works attacked all previous philosophy and historical scholarship.

David Hume expressed the skeptical challenge in ways that made him central to philosophical discussion up to and including our own day. His Treatise of Human Nature (17391740) argued for skepticism about both facts and reason. His critique of our ideas of causation reduces them to little more than a habit based on constant conjunction. And yet in typical skeptical fashion he showed how people could live with skepticism on the basis of probabilities and custom.

Immanuel Kant (17241804) was called the "all-destroyer" in his own day because of his rejection of so many other dogmatic philosophies. He adopted skeptical Greek vocabulary when he argued that we could have no knowledge of the noumenathe reality behind appearancesbut only of the phenomena. He saved free will and morality from scientific determinism only by reducing our knowledge of them to faith rather than knowledge. Other skeptics writing in German in his time included Salomon Maimon (17531800) and Gottlob Ernst "Aenesidemus" Schulze (17611833). When Carl Friedrich Stäudlin's Geist und Geschichte des Skepticismus (History and spirit of skepticism) of 1794 showed Hume facing Kant on the title page, it became clear these two thinkers had posed the skeptical challenge for the age: Stäudlin decried an unphilosophical skepticism even as he showed that the philosophical skeptics could not be refuted.


Francis Bacon (15611626), who was chancellor of England from 1618 to 1621, served as a spokesman for early natural philosophy, convinced that the experimental method would produce absolute certainty. Skeptics like François de La Mothe le Vayer (15851672) used many of the skeptical tropes to show that science could not produce certain knowledge. Other natural philosophers such as Marin Mersenne (15881648) and Pierre Gassendi (15921655) in France dispensed with the need for absolute certainty and defended experimental science on the ground that it could produce useful knowledge, in accordance with the phenomena, even without certainty. This attitude prevailed at the Royal Society in London as well. Skepticism could be used to sweep away the pretensions of Aristotelians and other dogmatists while leaving experimental scientists free to continue their work. In this spirit Robert Boyle (16271691) named his spokesman "Carneades" in The Sceptical Chymist (1661), and Joseph Glanvill (16361680) titled one of his books Scepsis Scientifica (1665).

Of all the fields that we now consider sciences, medicine was especially intertwined with skepticism. Sextus Empiricus was a practicing physician whose work influenced his philosophy, and each of the ancient schools of medicine had taken positions for or against philosophical dogmatism or skepticism. Ancient Hippocratic sources stressed the importance of skeptical observation and experience and the dangers of dogmatic theory in medicine. In early modern Europe the writings of Hippocrates (c. 460c. 377 b.c.e.) and Galen (c. 129c. 200 c.e.) were an important part of medical studies, and they introduced the student both to dogmatic medicine and to the skeptical critique.

Several prominent early modern physicians contributed to the literature on skepticism and medicine. Toulouse professor Francisco Sanches (c. 1550c. 1623) called himself "Carneades philosophus" and attacked Aristotelian science in his book Quod Nihil Scitur (1581; That nothing is known). The English physician and philosopher John Locke (16321704) may have picked up some of the skeptical elements in his philosophy from skeptical physician Thomas Sydenham (16241689). Martín Martínez (16841734), royal physician and president of the Royal Academy in Seville, was the author of Medicina Sceptica (17221724), which attacked dogmatic Galenism, and Philosophia Sceptica (1730), which introduced Gassendi and Descartes to Spain. Ernst Platner (17441818) was a German physician whose skeptical writings were influential in Kant's time.


Especially in the seventeenth century, skepticism made its way into historiography as writers began to question the received accounts of history. La Mothe le Vayer's On the Small Amount of Certainty in History (1668) and Pierre Bayle's Historical and Critical Dictionary (16971702) brought numerous historical errors to public attention. The only lasting solution was to learn to live with the appearances and accept lower standards for practical purposes instead of absolute certainty, as in natural science.

Throughout the early modern era skepticism was used to justify a wide variety of political stances, from quietist conservatism to radical activism.


The historical scholarship of Isaac la Peyrère (15961676), Baruch Spinoza (16321677), and Richard Simon (16381712) contributed to skepticism about the Bible. In response, throughout the early modern period it was common to accuse skeptics of atheism, libertinism, and immorality. But skeptics were not necessarily atheists. In fact, one of the most common uses of skepticism was its use by the self-described orthodox against pagan claims to truth, by the Lutherans and Calvinists against Catholic claims to infallibility, and by Catholics against Protestant claims to truth. Many religionists believed that their own truth was immune from skepticism, but one argument was that if all claims to truth can be demolished, one should accept traditional religion on faith. This position is known as fideism.

Various versions of fideism were widespread. Thinkers from Montaigne to Huet and Bayle to many figures in the eighteenth century wrote that skepticism cleared the way to faith by removing rationalist objections. Blaise Pascal (16231662) in France in the seventeenth century and Jean de Castillon (17091791) in Berlin in the eighteenth century Christianized skepticism by showing that, properly understood, it set the scene for Christianity. In the Critique of Pure Reason Kant famously wrote that he had had to deny knowledge in order to make room for faith (Preface to Second Edition [1787], B, xxx). Whether each such figure was sincere or was using fideism as a defense against possible persecution for heresy has been the subject of debate ever since.

See also Atheism ; Bayle, Pierre ; Descartes, René ; Humanists and Humanism ; Hume, David ; Kant, Immanuel ; Montaigne, Michel de ; Pascal, Blaise ; Spinoza, Baruch .


Borghero, Carlo. La certezza e la storia: Cartesianesimo, pirronismo e conoscenza storica. Milan, 1983.

Floridi, Luciano. Sextus Empiricus: The Transmission and Recovery of Pyrrhonism. New York, 2002.

Laursen, John Christian. The Politics of Skepticism in the Ancients, Montaigne, Hume, and Kant. Leiden and New York, 1992.

Popkin, Richard H. The History of Skepticism from Savonarola to Bayle. 4th edition. New York and Oxford, 2002.

Schmitt, Charles B. Cicero Scepticus: A Study of the Influence of the Academica in the Renaissance. The Hague, 1972.

Van Leeuwen, Henry G. The Problem of Certainty in English Thought 16301690. The Hague, 1970.

John Christian Laursen

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