Skepticism

The Roman philosopher and statesman Marcus Tullius Cicero (106–43 B.C.E.) is the chief source for Academic skepticism. His Academica (45 B.C.E.) reports on the teachings of Arcesilaus (315–240 B.C.E.) and Carneades (214–129 B.C.E.), both heads of the Academy, and he claims allegiance to the Academic school. St. Augustine of Hippo's earliest extant work, Contra Academicos (Against the Academics; 386 C.E.), is also an important source of knowledge about Academic skepticism.

Socrates can be placed at the origins of skepticism if it is understood that he only asked questions and did not teach positive doctrines. Plato and Aristotle strayed from his 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 in accordance with the eulogon (the reasonable) in the absence of truth. Carneades, also a master of arguing on both sides of every issue, refined this into the standard of the pithanon (the credible). Cicero translated this into Latin as probabile, setting the stage for the skeptics' claim to live by the probable in the absence of truth.

Manuscripts of Cicero's Academica were available in the Middle Ages to figures such as John of Salisbury (1115–1180), who used it to underpin defenses of liberty of thought and speech. The text was first printed at Rome in 1471, followed by numerous commentaries and annotations. By 1600 more than 100 editions had been published.

The Dutch humanist Desiderius Erasmus (1466?–1536) admired Academic skepticism in his Praise of Folly (1511), which provoked opposition from Christians like Philipp Melanchthon (1487–1560). Gianfrancesco Pico della Mirandola's Examen Vanitatis (1520) drew from both Cicero and Sextus Empiricus. Omer Talon emphasized the Academics' philosophical freedom from dogmatism in his Academia of 1547, and Petrus Ramus praised their rhetoric and style in Ciceronianus of 1557. Giulio Castellani (1528–1586) defended Aristotelianism against Academic skepticism in Adversus Marci Tullii Ciceronis (1558), arguing that disagreement is not as widespread as the skeptics claimed. Johannes Rosa (1532–1571) brought out a substantial early commentary on the Academica in German in 1571, and Pedro de Valencia (1555–1620) refashioned Academic skepticism in his own Academica of 1596, published in Spain.

Publication of Sextus Empiricus's works in the 1560s replaced Cicero as the chief source of information about ancient skepticism. After that point most authors drew their inspiration from both sources, so it is hard to speak of purely Academic skeptics from then on. One exception is David Hume (1711–1776), sometimes called an Academic skeptic, among other reasons because a character 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.