Skepticism

Of all the fields that in the early twenty-first century are considered sciences, medicine has been especially intertwined with skepticism. Sextus Empiricus was a practicing physician whose work influenced his philosophy. The writings of the Greek physicians Hippocrates (c. 460–c. 377 B.C.E.) and Galen (c. 129–c. 200 C.E.) stressed the importance of skeptical observation and experience and the dangers of dogmatic theory in medicine. Their work was an important part of medical education in early modern Europe, introducing the student to both dogmatic medicine and the skeptical critique.

Several prominent early modern physicians developed the connections between skepticism and medicine. The Toulouse professor Francisco Sanches (c. 1550–1623) called himself "Carneades philosophus," attacking Aristotelian science in his book Quod Nihil Scitur (That nothing is known; 1581). The English physician and philosopher John Locke (1632–1704) borrowed some of the skeptical elements in his philosophy from the skeptical physician Thomas Sydenham (1624–1689). Martín Martínez (1684–1734), royal physician and president of the Royal Medicine Academy of Medicine in Seville, published Medicina Sceptica (1722–1724), attacking dogmatic Galenism, and Philosophia Sceptica (1730), which introduced Descartes to Spain. The German physician Ernst Platner's (1744–1818) skeptical writings were influential in Kant's time.

The early natural scientist Francis Bacon (1561–1626) was convinced that the experimental method would produce absolute certainty. Skeptics like François de La Mothe Le Vayer (1583–1672) used skeptical tropes to show that science could not produce certain knowledge. Other philosopher-scientists, such as Marin Mersenne (1588–1648) and Pierre Gassendi (1592–1655) in France, rejected the need for certainty and defended experimental science on the ground that it is enough that it produces useful knowledge. This attitude prevailed at the Royal Society in London. Skepticism could sweep away the pretensions of Aristotelians and other dogmatists while leaving scientists free to continue their experiments. In this spirit, Robert Boyle (1627–1691) named his spokesman "Carneades" in The Sceptical Chymist (1661), and Joseph Glanvill (1636–1680) titled one of his books Scepsis Scientifica (1665).

By the twentieth century, natural science had pretty much left the skeptical path, claiming something close to a monopoly on truth and knowledge. But avatars of the skeptical tradition still emerge here and there in connection with the sciences. The philosopher of science Karl Popper (1902–1994) contended that scientific claims could never be absolutely verified, only falsified. Paul Feyerabend (1924–1994) was described as a Pyrrhonian for his generally skeptical attitude toward all scientific claims.