The Philosophy of Skepticism
Skepticism, or the philosophy of doubting, is a critical attitude or methodology that questions the claims of knowledge made by philosophers and others.
It has two main ideas: (1) that to arrive at truth one must believe everything to be false until it is proved to be true- a denial of the primary instinct which is to believe the opposite; and (2) that human knowledge can never arrive at truth- a denial of objective knowledge.
Skepticism has been known in various degrees, including the refusal to acknowledge that any knowledge is possible at all, the denial that any knowledge is valid if it is not derived from sense experience, and the denial of claims of knowledge in specific fields such as metaphysics, theology, or the sciences. Skepticism has contributed to the advancement of epistemology, or theories of knowledge, by forcing the critical analysis of all claims to knowledge and the rejection of unwarranted assumptions.
Skepticism arose as a necessary reaction to dogmatism, since the assertions of various dogmatic schools can be pitted against each other until all is a chaos of contradiction. Thus the Sophistic teaching of Protagoras and Gorgias arose (c. 440 BC) in opposition to the conflicting cosmological dogmas of Heracleitus and Parmenides and the ethical ideas of the city-states. Carneades, held a more moderate view of knowledge, maintained that beliefs acquired inductively from experience can be probable, but never certain.
The development of skepticism was halted for a century by the great constructive systems of Plato and Aristotle.
The first school of skepticism originated with Pyrrho of Elis (c. 300 BC), who concluded, like the Stoics and Epicureans, that the aim of life is individual happiness, attained only in mental serenity born of total submission.
This teaching was largely influenced by the Protagorean denial of the possibility of real knowledge on the ground that individual and momentary cognition alone is possible. The adherents of this school extended skepticism even to the principles of their own doubt. About AD 200 Sextus Empiricus attacked all forms of Graeco-Roman thought, especially the materialism of the Stoics. Sextus Empiricus provided a famous series of rules for avoiding judgments in his Adversus mathematicos and the Pyrrhonism hypotyposes .
With the Renaissance, the essayist Montaigne displayed a civilized skepticism, presaging the Enlightenment values of Bayle's Dictionnaire, 1697.
Rene Descartes utilized a skeptical attitude in his search for a sound basis for all knowledge.
Skepticism found its greatest exponent in the empirical philosopher Hume, who in his Treatise, 1739-40, opposed sense-impression to reason, denied the relation of cause and effect, and isolated perceptions; his sensational skepticism may therefore be termed the modern Protagoreanism.
The skeptical attitude can be observed in Kant, who reconciled it with dogmatism to produce criticism, and in Hegel who asserted that in every philosophical speculation there must be a skeptical moment.
In the 20th century skeptical attitudes are represented by the criticisms of metaphysics made by such philosophers as Rudolf Carnap and Bertrand Russell.