skepticism

/skep"teuh siz'euhm/, n.

1. skeptical attitude or temper; doubt.

2. doubt or unbelief with regard to a religion, esp. Christianity.

3. (cap.) the doctrines or opinions of philosophical Skeptics; universal doubt.

Also, scepticism.

[1640-50; < NL scepticismus, equiv. to L sceptic(us) SKEPTIC + -ismus -ISM]

Syn. 1. questioning, probing, testing. 2. disbelief, atheism, agnosticism.

Ant. 2. faith.

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Philosophical doubting of knowledge claims in various areas.

From ancient to modern times, skeptics have challenged accepted views in metaphysics, science, morals, and religion. Pyrrhon of Elis (с 360–272 BC) sought mental peace by avoiding commitment to any particular view; his approach gave rise in the lst century BC to Pyrrhonism, proponents of which sought to achieve suspension of judgment by systematically opposing various knowledge claims. One of its later leaders, Sextus Empiricus (2nd or 3rd century AD), strove for a state of imperturbability. Modern skeptical philosophers include Michel de Montaigne, Pierre Bayle, and David Hume.

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▪ philosophy

Introduction

also spelled  Scepticism 

      the philosophical attitude of doubting knowledge claims set forth in various areas. Skeptics have challenged the adequacy or reliability of these claims by asking what they are based upon or what they actually establish. They have raised the question whether such claims about the world are either indubitable or necessarily true, and they have challenged the alleged grounds of accepted assumptions. Practically everyone is skeptical about some knowledge claims; but the Skeptics have raised doubts about any knowledge beyond the contents of directly felt experience. The original Greek meaning of skeptikos was “an inquirer,” someone who was unsatisfied and still looking for truth.

      From ancient times onward Skeptics have developed arguments to undermine the contentions of dogmatic philosophers, scientists, and theologians. The Skeptical arguments and their employment against various forms of dogmatism have played an important role in shaping both the problems and the solutions offered in the course of Western philosophy. As ancient philosophy and science developed, doubts arose about basic accepted views of the world. In ancient times Skeptics challenged the claims of Platonism, Aristotelianism, and Stoicism, and in the Renaissance those of Scholasticism and Calvinism. After Descartes, Skeptics attacked Cartesianism and other theories justifying the “new science.” Later, a Skeptical offensive was levelled against Kantianism and then against Hegelianism. Each Skeptical challenge led to new attempts to resolve the difficulties. Skepticism, especially since the Enlightenment, has come to mean disbelief—primarily religious disbelief (atheism)—and the Skeptic has often been likened to the village atheist.

Various senses and applications

      Skepticism developed with regard to various disciplines in which men claimed to have knowledge. It was questioned, for example, whether one could gain any certain knowledge in metaphysics (the study of the nature and significance of being as such) or in the sciences. In ancient times a chief form was medical Skepticism, which questioned whether one could know with certainty either the causes or cures of diseases. In the area of ethics doubts were raised about accepting various mores and customs and about claiming any objective basis for making value distinctions. Skepticisms about religion have questioned the doctrines of different traditions. Certain philosophies, like those of Hume (Hume, David) and Kant (Kant, Immanuel), have seemed to show that no knowledge can be gained beyond the world of experience and that one cannot discover the causes of phenomena. Any attempt to do so, as Kant argued, leads to antinomies, contradictory knowledge claims. A dominant form of Skepticism, the subject of this article, concerns knowledge in general, questioning whether anything actually can be known with complete or adequate certainty. This type is called epistemological (epistemology) Skepticism.

      Kinds of epistemological Skepticism can be distinguished in terms of the areas in which doubts are raised; that is, whether they be directed toward reason, toward the senses, or toward knowledge of things-in-themselves. They can also be distinguished in terms of the motivation of the Skeptic—whether he is challenging views for ideological reasons or for pragmatic or practical ones to attain certain psychological goals. Among the chief ideological motives have been religious or antireligious concerns. Some Skeptics have challenged knowledge claims so that religious ones could be substituted—on faith. Others have challenged religious knowledge claims in order to overthrow some orthodoxy. Kinds of Skepticism also can be distinguished in terms of how restricted or how thoroughgoing they are—whether they apply only to certain areas and to certain kinds of knowledge claims or whether they are more general and universal.

Ancient Skepticism

      Historically, skeptical philosophical attitudes began to appear in pre-Socratic thought. In the 5th century BC, the Eleatic (Eleaticism) philosophers, known for reducing reality to a static One, questioned the reality of the sensory world, of change and plurality, and denied that reality could be described in the categories of ordinary experience. On the other hand, the Ephesian philosopher of change Heracleitus and his pupil Cratylus thought that the world was in such a state of flux that no permanent, unchangeable truth about it could be found; and Xenophanes, a wandering poet and philosopher, doubted whether man could distinguish true from false knowledge.

      A more developed Skepticism appeared in some of Socrates' (Socrates) views and in a couple of the Sophists (Sophist) (see below Sophists (Sophist)). Socrates, in the early Platonic dialogues, was always questioning the knowledge claims of others; and in the Apology, he said that all that he really knew was that he knew nothing. Socrates' enemy, the Sophist Protagoras, contended that man is the measure of all things. This thesis was taken as a kind of skeptical relativism: no views are ultimately true, but each is merely one man's opinion. Another Sophist, Gorgias, advanced the skeptical-nihilist thesis that nothing exists; and if something did exist, it could not be known; and if it could be known, it could not be communicated.

      The putative father of Greek Skepticism is Pyrrhon Of Elis (c. 360–c. 272 BC), who tried to be a living Skeptic. He avoided committing himself to any views about what was actually going on and acted only according to appearances. In this way he sought happiness or at least mental peace.

      The first school of Skeptical philosophy developed in Plato's Academy in the 3rd century BC and was thus called “Academic” Skepticism. Starting from the skeptical side of Socrates, its leaders, Arcesilaus (316/315–c. 241 BC) and Carneades (214/213–129/128 BC), set forth a series of epistemological arguments to show that nothing could be known, challenging primarily the two foremost schools, those of the Stoics and Epicureans. They denied that any criteria could be found for distinguishing the true from the false; instead, only reasonable or probable standards could be established for knowledge. This limited or probabilistic Skepticism was the view of the Academy until the 1st century BC, when Cicero (Cicero, Marcus Tullius) was a student there. His Academica and De natura deorum are the main sources for knowledge of this movement. (St. Augustine's Contra academicos is an answer to Cicero's views.)

      The other major form of ancient Skepticism was Pyrrhonism, apparently developed by medical Skeptics in Alexandria. Beginning with Aenesidemus (1st century BC), this movement, named after Pyrrhon, criticized the Academic Skeptics because they claimed to know too much, namely, that nothing could be known and that some things are more probable than others. The Pyrrhonians advanced a series of tropes, or ways of opposing various kinds of knowledge claims, in order to bring about epochē (suspense of judgment). The Pyrrhonian attitude is preserved in the writings of one of its last leaders, Sextus Empiricus (2nd or 3rd century AD). In his Outlines of Pyrrhonism and Adversus mathematicos, Sextus presented the tropes developed by previous Pyrrhonists. The 10 tropes attributed to Aenesidemus showed the difficulties to be encountered in ascertaining the truth or reliability of judgments based on sense information, owing to the variability and differences of human and animal perceptions. Other arguments raised difficulties in determining whether there are any reliable criteria or standards—logical, rational, or otherwise—for judging whether anything is true or false. To settle any disagreement, a criterion seems to be required. Any purported criterion, however, would appear to be based on another criterion, thus requiring an infinite regress of criteria, or else it would be based upon itself, which would be circular. Sextus offered arguments to challenge any claims of dogmatic philosophers to know more than what is evident; and in so doing he presented in one form or another practically all of the skeptical arguments that have ever appeared in subsequent philosophy.

      Sextus said that his arguments were aimed at leading people to a state of ataraxia (unperturbability). People who thought that they could know reality were constantly disturbed and frustrated. If they could be led to suspend judgment, however, they would find peace of mind. In this state of suspension they would neither affirm nor deny the possibility of knowledge but would remain peaceful, still waiting to see what might develop. The Pyrrhonist did not become inactive in this state of suspense but lived undogmatically according to appearances, customs, and natural inclinations.

Medieval Skepticism

      Pyrrhonism ended as a philosophical movement in the late Roman Empire, as religious concerns became paramount. In the Christian Middle Ages the main surviving form of Skepticism was the Academic, described in St. Augustine's (Augustine, Saint) Contra academicos. Augustine, before his conversion, had found Cicero's views attractive and had overcome them only through revelation. With faith, he could seek understanding. Augustine's account of Skepticism and his answer to it provided the basis for medieval discussions.

      In Islāmic Spain, where there was more contact with ancient learning, a form of antirational Skepticism developed among Muslim and Jewish theologians. Al-Ghazāli (Ghazālī, al-), an Arab theologian of the 11th and early 12th centuries, and his Jewish contemporary Judah ha-Levi (c. 1075/c. 1085–c. 1141), who was a poet and physician as well as a philosopher, offered skeptical challenges (much like those later employed by the occasionalist Nicolas Malebranche and by David Hume) against the contemporary Aristotelians in order to lead people to accept religious truths in mystical faith. This kind of fideism also appears in the late Middle Ages in the German cardinal and philosopher Nicolaus of Cusa's (Nicholas Of Cusa) advocacy of learned ignorance as the way to religious knowledge.

Modern Skepticism

      Modern Skepticism emerged in the 16th century, not from medieval views but from the intellectual crises of the Renaissance and Reformation and from the rediscovery of the Skeptical classics. The voyages of exploration; the humanistic rediscovery of the learning of ancient Greece, Rome, and Palestine; and the new science—all combined to undermine confidence in man's accepted picture of the world. The religious controversy between the Protestants and Catholics raised fundamental epistemological issues about the bases and criteria of religious knowledge. At the same time the texts of Cicero and Sextus became available again. (Sextus' Outlines of Pyrrhonism [Hypotyposeis] was published in Latin in 1562, his Adversus matematicos in 1569, and the Greek texts of both in 1621.)

In the Reformation

      The fundamental skeptical issues raised by the Reformation appeared in the debate between the outstanding humanist scholar Erasmus (Erasmus, Desiderius) and Luther (Luther, Martin). Erasmus, using Academic skeptical materials, insisted that the issues in dispute could not be resolved, that one should therefore suspend judgment and remain with the church. Luther insisted, on the other hand, that true and certain religious knowledge could and must be gained through conscience. Erasmus' view developed into a Christian Skepticism, accepting traditional Christianity on faith after seeing that no adequate evidence existed. Luther's view, and later that of Calvin (Calvin, John), proposed a new criterion—that of inner experience—while the Catholics of the Counter-Reformation employed Pyrrhonian and Academic arguments to undermine the criterion.

      Following after Erasmus, another humanist, Giovanni Pico della Mirandola (Pico della Mirandola, Giovanni, Conte Di Concordia) II (nephew of the famous count of the same name) and H.C. Agrippa von Nettesheim (Agrippa von Nettesheim, Heinrich Cornelius), a stormy occult philosopher and physician, employed the skeptical arguments against Scholasticism, Renaissance Naturalism, and many other views to win people to the “true religion.” The Catholic scholar Gentian Hervet, in the preface to his 1569 edition of Sextus, saw the Skeptical arguments as the definitive answer to Calvinism and the way to true Christianity.

In the 17th century

      The new concern with Skepticism was given a general philosophical formulation by Michel de Montaigne (Montaigne, Michel de) and his cousin Francisco Sanches (Sanches, Francisco). Montaigne in Apology for Raimond Sebond and Sanches in Quod nihil scitur, both written in 1576, explored the human epistemological situation and showed that man's knowledge claims in all areas were extremely dubious. Montaigne recommended living according to nature and custom and accepting whatever God reveals, and Sanches advocated recognizing that nothing can be known and then trying to gain what limited information one can through empirical scientific means.

      Montaigne's Skepticism was extremely influential in the early 17th century. His followers, Pierre Charron, J.-P. Camus, La Mothe Le Vayer, and others, further popularized his views. Various French Counter-Reformers used the arguments of Montaigne and Sextus to undermine Calvinism. Montaigne's Skepticism opposed all sorts of disciplines, including the new science, and was coupled with a fideism that many suspected to be insincere.

      In the 1620s efforts to refute or mitigate this new Skepticism appeared. A Christian Epicurean, Pierre Gassendi (Gassendi, Pierre), himself originally a Skeptic, and Marin Mersenne (Mersenne, Marin), one of the most influential figures in the intellectual revolution of the times, while retaining epistemological doubts about knowledge of reality yet recognized that science provided useful and important information about the world. The constructive Skepticisms of Gassendi and Mersenne, and later of members of the Royal Society of England like Bishop John Wilkins and Joseph Glanvill, developed the attitude of Sanches into a hypothetical, empirical interpretation of the new science.

      René Descartes (Descartes, René) offered a fundamental refutation of the new Skepticism, contending that, by applying the skeptical method of doubting all beliefs that could possibly be false (due to suffering illusions or being misled by some power), one would discover a truth that is genuinely indubitable, viz., “I think, therefore I am” (cogito ergo sum (cogito, ergo sum)), and that from this truth one could discover the criterion of true knowledge, viz., that whatever is clearly and distinctly conceived is true. Using this criterion, one could then establish: God's existence, that he is not a deceiver, that he guarantees our clear and distinct ideas, and that an external world exists that can be known through mathematical physics. Descartes, starting from Skepticism, claimed to have found a new basis for certitude and for knowledge of reality. Throughout the 17th century Skeptical critics—Mersenne, Gassendi, the reviver of Academic philosophy Simon Foucher, and Pierre-Daniel Huet, one of the most learned men of the age—sought to show that Descartes had not succeeded, and that, if he sincerely followed his skeptical method, his new system could only lead to complete Skepticism. They challenged whether the cogito proved anything, or whether it was indubitable; whether Descartes' method could be successfully applied, or whether it was certain; and whether any of the knowledge claims of Cartesianism were really true. Nicolas Malebranche (Malebranche, Nicolas), the developer of occasionalism, revised the Cartesian system to meet the Skeptical attacks only to find his efforts challenged by the new Skeptical criticisms of Foucher and by the contention of the Jansenist philosopher Antoine Arnauld (Arnauld, Antoine) that Malebranchism led to a most dangerous Pyrrhonism.

      Various English philosophers culminating in Locke (Locke, John) tried to blunt the force of Skepticism by appealing to common sense and to the “reasonable” man's inability to doubt everything. They admitted that there might not be sufficient evidence to support the knowledge claims extending beyond immediate experience. But this did not actually require that everything be doubted; by using standards of common sense, an adequate basis for many beliefs could be found. Blaise Pascal (Pascal, Blaise), who presented the case for Skepticism most forcefully in his Pensées, still denied that there can be a complete Skepticism; for nature prevents it. Lacking rational answers to complete Skepticism, man's only recourse lies in turning to God for help in overcoming doubts.

      The culmination of 17th-century Skepticism appears in the writings of Pierre Bayle (Bayle, Pierre), especially in his monumental Dictionnaire historique et critique (1697–1702). Bayle, a superb dialectician, challenged philosophical, scientific, and theological theories, both ancient and modern, showing that they all led to perplexities, paradoxes, and contradictions. He argued that the theories of Descartes, Spinoza, Leibniz, and Malebranche, when skeptically analyzed, cast in doubt all information about the world, even whether a world exists. Bayle skillfully employed Skeptical arguments about such things as sense information, human judgments, logical explanations, and the criteria of knowledge in order to undermine confidence in human intellectual activity in all areas. Bayle suggested that man should abandon rational activity and turn blindly to faith and revelation; he can therefore only follow his conscience without any criterion for determining true faith. Bayle showed that the interpretations of religious knowledge were so implausible that even the most heretical views, like Manichaeism, known for its cosmic dualism of good and evil, and Atheism, made more sense. As a result Bayle's work became “the arsenal of the Enlightenment,” and he was regarded as a major enemy of religion.

In the 18th century

      Most 18th-century thinkers gave up the quest for metaphysical knowledge after imbibing Bayle's arguments. George Berkeley (Berkeley, George), an Empiricist and Idealist, fought Skeptical doubts by identifying appearance and reality and offering a spiritualistic metaphysics. He was immediately seen as just another Skeptic since he was denying the world beyond experience.

      Bayle's chief 18th-century successor was David Hume. Combining empirical and skeptical arguments, Hume charged that neither inductive nor deductive evidence could establish the truth of any matter of fact. Knowledge could only consist of intuitively obvious matters or demonstrable relations of ideas but not of anything beyond experience; the mind can discover no necessary connections within experience nor any root causes of experience. Beliefs about the world are based not upon reason or evidence nor even upon appeal to the uniformity of nature but only on habit and custom. Beliefs cannot be justified. Belief that there is an external world, a self, a God is common; but there is no adequate evidence for it. Although it is natural to hold these convictions, they are inconsistent and epistemologically dubious. “Philosophy would render us entirely Pyrrhonian, were not Nature too strong for it.” The beliefs that a man is forced to hold enable him to describe the world scientifically, but when he tries to justify them he is led to complete Skepticism. Before he goes mad with doubts, however, Nature brings him back to common sense, to unjustifiable beliefs. Hume's fideism was a natural rather than a religious one; it is only animal faith that provides relief from complete doubt. The religious context of Skepticism from Montaigne to Bayle had been removed, and man was left with only his natural beliefs, which might be meaningless or valueless.

      The central themes in Hume's Skeptical analysis—the basis of induction and causality, knowledge of the external world and the self, proofs of the existence of God—became the key issues of later philosophy. Hume's contemporary Thomas Reid (Reid, Thomas) hoped to rebut Hume's Skepticism by exposing it as the logical conclusion of the basic assumptions of modern philosophy from Descartes onward. Such disastrous assumptions should be abandoned for commonsensical principles that have to be believed. As Hume and Kant saw, Reid had not answered Hume's Skepticism but had only sidestepped the issue by appealing to commonsensical living. This provided, however, neither a theoretical basis for beliefs nor a refutation of the arguments that questioned them.

      Kant (Kant, Immanuel) saw that Hume had posed a most fundamental challenge to all human knowledge claims. To answer him, it had to be shown not that knowledge is possible but how it is possible. Kant combined a Skepticism toward metaphysical knowledge with the contention that certain universal and necessary conditions are involved in having experience and describing it. In terms of these it is possible to have genuine knowledge about the forms of all possible experience, space and time, and about the categories in which all experience is described. Any effort to apply this beyond all possible experience, however, leads into contradictions and Skepticism. It is not possible to know about things-in-themselves nor about the causes of experience.

      Though Kant thought that he had resolved the Skeptical problems, some of his contemporaries saw his philosophy as commencing a new Skeptical era. G.E. Schulze (or Schulze-Aenesidemus) a notable critic of Kantianism, insisted that, on Kant's theory, no one could know any objective truths about anything; he could only know the subjective necessity of his views. The Jewish critic Salomon Maimon (Maimon, Salomon) contended that, though there are such things as a priori concepts, their application to experience is always problematical, and whether they apply can only be found through experience. Hence, the possibility of knowledge can never be established with certainty. Assured truth on the basis of concepts is possible only of human creations, like mathematical ideas, and it is questionable whether these have any objective truth. The thesis that human creativity is the basis of truth, however, was soon to be developed by Johann G. Fichte (Fichte, Johann Gottlieb), a leading German Idealist, as a new way of transcending Skepticism.

      Another Skeptical critic of Kant, J.G. Hamann (Hamann, Johann Georg), saw in Hume's and Kant's work a new basis for fideism. If knowledge of reality cannot be gained by rational means, then one must turn to faith. Based on Hume's efforts, Hamann advanced an antirational Skepticism in an effort to convince Kant to become a fideistic Christian. Hamann's kind of fideism was also developed in France by Catholic opponents of the French Revolution and liberalism—like Joseph de Maistre and H.-F.-R. de Lamennais.

In recent and contemporary philosophy

      Irrational Skepticism was developed into Existentialism by Søren Kierkegaard (Kierkegaard, Søren) in the 19th century. Using traditional Skeptical themes to attack Hegelianism and liberal Christianity, Kierkegaard stressed the need for faith. Only by an unjustified and unjustifiable “leap into faith” could certainty be found—which would then be entirely subjective rather than objective. Modern neo-orthodox and Existentialist theologians have argued that Skepticism highlights man's inability to find any ultimate truth except through faith and commitment. Nonreligious forms of this view have been developed by Existentialist writers like Albert Camus (Camus, Albert), combining the epistemological Skepticism of Kierkegaard with the religious and value Skepticism of Nietzsche (Nietzsche, Friedrich). The rational and scientific examination of the world shows it to be unintelligible and absurd; and if God is dead, as Nietzsche proclaimed, then the world is ultimately meaningless. But it is necessary to struggle with it. It is thus through action and commitment that one finds whatever personal meaning one can, though it has no objective significance.

      Other kinds of Skepticism appear in various forms of recent and contemporary philosophy. The English Idealist F.H. Bradley (Bradley, F H) used classical Skeptical arguments in his Appearance and Reality: A Metaphysical Essay to contend that the world could not be understood empirically or materialistically; true knowledge could be reached only by transcending the world of appearance.

      George Santayana (Santayana, George), an American critical Realist, in Scepticism and Animal Faith, presented a naturalistic Skepticism. Any interpretation of immediate or intuited experience is open to question. To make life meaningful, however, men make interpretations by “animal faith,” according to biological and social factors. The resulting beliefs, though unjustified and perhaps illusory, enable them to persevere and find the richness of life.

      Types of Skepticism also appear in Logical Positivism and various forms of linguistic philosophy (analytic philosophy). The attack on speculative metaphysics developed by the physicist and early Positivist Ernst Mach (Mach, Ernst), by Bertrand Russell (Russell, Bertrand), and by Rudolf Carnap (Carnap, Rudolf), a leader in the Vienna Circle, where Logical Positivism was nourished, incorporated a Skepticism about the possibility of gaining knowledge beyond experience or logical tautologies. Russell and the important philosopher of science Karl Popper (Popper, Sir Karl) have further stressed the unjustifiability of the principle of induction, and Popper has criticized theories of knowledge based upon empirical verification. A founder of linguistic analysis, Fritz Mauthner, has set forth a Skepticism in which any language is merely relative to its users and thus subjective. Every attempt to tell what is true just leads one back to linguistic formulations, not to objective states of affairs. The result is a complete Skepticism about reality—a reality that cannot even be expressed except in terms of what he called godless mystical contemplation. Mauthner's linguistic Skepticism bears some affinities to the views expressed in Ludwig Wittgenstein's Tractatus Logico-Philosophicus.

Criticism and evaluation

      In Western thought Skepticism has raised basic epistemological issues. In view of the varieties of human experience, it has questioned whether it is possible to tell which are veridical. The variations that occur in different perceptions of what is presumed to be one object raise the question of which is the correct view. The occurrence of illusory experiences raises the question of whether it is really possible to distinguish illusions and dreams from reality. The criteria employed can be questioned and require justification. On what basis does one tell whether one has the right criteria? By other criteria? Then, are these correct? On what standards? The attempt to justify criteria seems either to lead to an infinite regress or to just stop arbitrarily. If an attempt is made to justify knowledge claims by starting with first principles, what are these based upon? Can it be established that these principles cannot possibly be false? If so, is the proof itself such that it cannot be questioned? If it is claimed that the principles are self-evident, can one be sure of this, sure that one is not deceived? And can one be sure that one can recognize and apply the principles correctly? Through such questioning, Skeptics have indicated the basic problems that an investigator would have to resolve before he could be certain of possessing knowledge; i.e., information that could not possibly be false.

      Critics have contended that Skepticism is both a logically and a humanly untenable view. Any attempt to formulate the position will be self-refuting since it will assert at least some knowledge claims about what is supposed to be dubious. Montaigne (Montaigne, Michel de) suggested that the Skeptics needed a nonassertive language, reflecting the claim of Sextus that the Skeptic does not make assertions but only chronicles his feelings. The strength of Skepticism lies not in whether it can be stated consistently but upon the effects of its arguments on dogmatic philosophers. As Hume said, Skepticism may be self-refuting, but in the process of refuting itself it undermines dogmatism. Skepticism, Sextus said, is like a purge that eliminates itself as well as everything else.

      Critics have claimed that anyone who tried to be a complete Skeptic, denying or suspending all judgments about ordinary beliefs, would soon be driven insane. Even Hume (Hume, David) thought that the complete Skeptic would have to starve to death and would walk into walls or out of windows. Hume, therefore, separated the doubting activity from natural practical activities in the world. Skeptical philosophizing went on in theory, while believing occurred in practice. Sextus and the contemporary Norwegian Skeptic Arne Naess have said, on the other hand, that Skepticism is a form of mental health. Instead of going mad, the Skeptic—without commitment to fixed positions—can function better than the dogmatist.

      Some recent thinkers like A.J. Ayer (Ayer, Sir A.J.) and John Austin (Austin, John Langshaw) have contended that Skepticism is unnecessary. If knowledge is defined in terms of satisfying meaningful criteria, then knowledge is open to all. The Skeptics have raised false problems, because it is, as a matter of fact, possible to tell that some experiences are illusory since we have criteria for distinguishing them from actual events. We do resolve doubts and reach a state of knowledge through various verification procedures, after which doubt is meaningless. Naess, in his book Scepticism, has sought to show, however, that, on the standards offered by Ayer and Austin, one can still ask if knowledge claims may not turn out to be false and hence that Skepticism has still to be overcome.

      Skepticism throughout history has played a dynamic role in forcing dogmatic philosophers to find better or stronger bases for their views and to find answers to the Skeptical attacks. It has forced a continued reexamination of previous knowledge claims and has stimulated creative thinkers to work out new theories to meet the Skeptical problems. The history of philosophy can be seen, in part, as a struggle with Skepticism. The attacks of the Skeptics also have served as a check on rash speculation; the various forms of modern Skepticism have gradually eroded the metaphysical and theological bases of European thought. Most contemporary thinkers have been sufficiently affected by Skepticism to abandon the search for certain and indubitable foundations of human knowledge. Instead, they have sought ways of living with the unresolved Skeptical problems through various forms of naturalistic, scientific, or religious faiths.

Richard H. Popkin

Additional Reading

The basic statements and arguments of various forms of Skepticism are given in: (Academic Skepticism)—Cicero, Academica and De natura deorum, both with trans. by H. Rackham, Loeb Classical Library (1956). (Pyrrhonian Skepticism)—Sextus Empiricus, Adversus Mathematicos, with trans. by R.G. Bury, Loeb Classical Library: vol. 1–2, Against the Logicians and Outlines of Pyrrhonism (1933–36); vol. 3, Against the Physicists, Against the Ethicists (1936); vol. 4, Against the Professors (1959–60); and Scepticism, Man and God: Selections from the Major Writings of Sextus Empiricus, ed. by P. Hallie, trans. by S.G. Etheridge (1964). (Renaissance Skepticism)—Michel de Montaigne, “L'Apologie de Raimond Sebond,” in Pierre Villey (ed.), Les Essais de Michel de Montaigne, new ed. (1922). (Skepticism and fideism)—Blaise Pascal, Pensées, ed. by L. Brunschvicg (1951). (Skepticism in relation to modern philosophy)—Pierre Bayle, Dictionnaire historique et critique, esp. the articles “Pyrrho” and “Zeno of Elea,” both of which appear in Bayle's Historical and Critical Dictionary: Selections, trans. and ed. by Richard H. Popkin (1965); David Hume, Dialogues Concerning Natural Religion, ed. by N. Kemp Smith (1947); Enquiries Concerning the Human Understanding and Concerning the Principles of Morals, 2nd ed. (1957), and A Treatise of Human Nature, both ed. by L.A. Selby-Bigge (1958).The standard studies of ancient Skepticism are: Edwyn R. Bevan, Stoics and Sceptics (1959); Victor Brochard, Les Sceptiques grecs (1887); Norman MacColl, The Greek Sceptics from Pyrrho to Sextus (1869); Mary Mills Patrick, The Greek Sceptics (1929); Leon Robin, Pyrrhon et le scepticisme grec (1944); and Eduard Zeller, The Stoics, Epicureans and Sceptics, trans. by O.J. Reichel (1880). A fine modern study of the epistemological problems involved in ancient Skepticism is Charlotte L. Stough, Greek Skepticism (1969). See also Raoul Richter, Der Skeptizismus in der Philosophie (1904–08); Richard H. Popkin, “Skepticism,” Encyclopedia of Philosophy, vol. 7, pp. 449–461 (1967), which contains a bibliography on the subject; these examine Skepticism from ancient times to the 19th century. John Owen, The Skeptics of the French Renaissance (1893), is an interesting discussion of Renaissance and 17th-century Skepticism, though not particularly scholarly. Don Cameron Allen, Doubt's Boundless Sea: Skepticism and Faith in the Renaissance (1964); and Richard H. Popkin, The History of Scepticism from Erasmus to Descartes, rev. ed. (1968), which contains a lengthy bibliography, are studies of Renaissance Skepticism and its impact on philosophy and religion. Richard H. Popkin, “Berkeley and Pyrrhonism,” Review of Metaphysics, 5:223–246 (1951–52); “David Hume and the Pyrrhonian Controversy,” ibid., 6:65–81 (1952–53); “David Hume: His Pyrrhonism and His Critique of Pyrrhonism,” Philosophical Quarterly, 1:385–407 (1950–51); “The High Road to Pyrrhonism,” American Philosophical Quarterly, 2:1–15 (1965); “The Skeptical Crisis and the Rise of Modern Philosophy,” Review of Metaphysics, 7:132–151, 307–322, 499–510 (1953–54); “The Skeptical Precursors of David Hume,” Philosophy and Phenomenological Research, 16:61–71 (1955–56); and “Scepticism in the Enlightenment,” in T. Bestermann (ed.), Studies on Voltaire and the Eighteenth Century, 26:1321–1345 (1963), are specialized studies on aspects of Skepticism in relation to modern philosophy. Arne Naess, Scepticism (1968), is a most interesting attempt to clarify Skepticism in relation to contemporary thought and to defend it as a viable outlook in modern times. Benson Mates, Skeptical Essays (1981), discusses epistemological problems and free will.

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