University of Virginia Library

SKEPTICISM IN
MODERN THOUGHT

This article will deal with skepticism as a philo-
sophical view, as a set of arguments directed against
traditional philosophies, theologies, and beliefs, and as
a critical view countering various positive intellectual
positions. In these senses, skepticism encompasses both
the small persistent group of thinkers who declared
themselves philosophical skeptics, as well as a much
larger group who made use of skeptical materials and
attitudes to develop their own positions, and often, in
so doing incorporated a portion of the skeptical view-
point in their work. The latter group are skeptics in
varying degrees depending upon how extensive their

incorporation of skeptical views in their own positions
may be, and how they try to construct another position
to overcome the skeptical difficulties they raise against
their opponents. As we shall see, even among the
declared skeptics there are major variations in posi-
tions, and among those who are partially skeptics, or
skeptics with regard to certain areas of intellectual
endeavor (which almost anyone is to some extent), the
variations are still more pronounced. This article will
deal then with avowed skeptics, such as Montaigne,
Bayle, and Hume, with those who utilize skeptical
materials to reach new viewpoints, such as Descartes
and Hegel, and with those who are skeptics with regard
to certain kinds of knowledge claims, such as Spinoza
and Kant.

Modern skepticism, which played a great role in the
development of modern thought, entered the intellec-
tual arena in the sixteenth century. Earlier forms of
philosophical skepticism had appeared in ancient
Greece, and had been systematized during the
Hellenistic period into a series of argumentative posi-
tions attacking various forms of dogmatic philosophy.
The Academic skeptics of the later Platonic Academy,
Arcesilaus and Carneades, criticized the views of the
Stoic and Epicurean philosophers, seeking to show that
nothing could be known, in the sense of gaining
unquestionable knowledge about the real nature of
things. Their arguments appear in Cicero's De
academica and De natura deorum (first century B.C.).
The Academics instead advocated a kind of probablism
or denial of certainty.

In contrast to the strong negative position of the
Academic skeptics, another skeptical school developed
from the noncommittal position of Pyrrho of Elis.
Aenesidemus, an Alexandrian of the first century B.C.,
presented a series of attacks on the dogmatists and the
Academics, leading to a suspension of judgment about
whether anything can or cannot be known in meta-
physics or ethics. The Pyrrhonians developed a series
of “tropes” that is, skeptical reasonings, leading to a
mental state of neutrality and suspension of judgment
(epochē) about all matters that are not immediately
evident. In this state of imperturbability, they said, one
would finally find the goal of all Hellenistic philosophy:
a life of intellectual quietude and peace of mind. The
arguments of the Pyrrhonians were collected by one
of their last leaders, Sextus Empiricus (second or third
century A.D.) in his Pyrrhonian Hypotyposes and
Adversus mathematicos.

The two skeptical positions played an important role
in Hellenistic thought, but gradually died out as reli-
gious movements began to dominate the late Roman
world. The last major sign of skeptical concern appears
in Saint Augustine's early philosophical dialogues, es
pecially his Contra academicos (fifth century A.D.).
After Augustine there seems to have been little further
interest in the skeptical attacks.

In the Middle Ages, though there were at least two
Latin translations of the writings of Sextus Empiricus,
there does not seem to have been any serious consid-
eration of skeptical themes. In the Muslim world, how-
ever, where more direct contact with classical sources
existed, some of the antirational theologians made use
of skeptical materials in order to challenge the meta-
physical views of the Jewish and Islamic philosophers.
Both Judah Ha-Levi and Al-Ghazali attacked the
claims of their contemporaries to knowledge of the
necessary conditions of the universe, offering argu-
ments, much like those later used by Malebranche and
Hume. Judah Ha-Levi and Al-Ghazali employed skep-
ticism to lead people to their religious mystical views.

Modern skepticism does not derive from these medi-
eval views, but from the combined effect of several
monumental cultural changes in the sixteenth century,
and the rediscovery by the West of the ancient skepti-
cal texts.

At the beginning of the sixteenth century, man's
picture of the earth was being shaken and transformed
by the results of the voyages of exploration. Columbus
did not merely discover a new fact, that there was an
inhabited land mass between Europe and Asia, but, as
Vespucci realized, that there was a New World which
challenged many of the assumptions and beliefs about
the old one. Almost all previous views about the world
had become untrue, and the science and philosophy
that had led to such views could no longer be relied
upon. The new worlds discovered by the early ex-
plorers appeared to function very well without the
social, political, or religious institutions of Christianity,
and posed a basic skeptical challenge to the European
and Judeo-Christian claims about the nature and des-
tiny of man. The influence of the idea of the “Noble
Savage,” presented from Columbus to Montaigne and
to Rousseau, Voltaire, and others, made intellectuals
increasingly critical if not skeptical of their own or
accepted valuations of civilizations.

A different kind of skeptical attack came from the
humanists who had rediscovered Greece and Rome, as
well as the riches of early Judaism and Christianity.
Led by Erasmus and Vives they cast doubt upon the
whole intellectual edifice that had been constructed
in the high Middle Ages. They questioned the methods,
purposes, and achievements of the scholastic
universities, and portrayed the entire intellectual en-
deavor of the universities as sterile, futile, and bank-
rupt. And after Erasmus' In Praise of Folly (Moriae
encomium, 1509), it was hard to take the institutional
intellectual world seriously. Erasmus had not refuted

scholasticism in any philosophical way, but had so
ridiculed it that it could no longer be considered a
way to knowledge. Only a totally different approach,
that of humanistic scholarship, could help.

One form of these researches further intensified the
skeptical atmosphere. Jewish scholars fleeing from
Spain, brought the Cabbala into Europe, with its secret
way of discovering the truth. This, coupled with the
rediscovery of the Greek magical writings of Hermes
Trismegistus, the researches of the alchemists, the
astrologers, and the numerologists, convinced many
humanists that the normal ways of gaining knowledge
had to be rejected in favor of esoteric ones. Thinkers
during the Renaissance era, like Pico della Mirandola,
Ficino, Reuchlin, and Agrippa von Nettesheim (espe-
cially the latter), cast doubt upon previous claims to
knowledge.

The “new scientists,” in combining some of the
humanistic learning about ancient views and esoteric
theories with empirical research, raised further skepti-
cal questions about the accepted views of man and his
universe. Copernicus, Tycho Brahe, Kepler, Paracelsus,
Servetus, Vesalius, and others, all contributed to
undermining confidence in previous theories and
methods.

In addition to these factors, the religious develop-
ments of the times helped lead the European intellec-
tual world into a general “skeptical crisis.” The ques-
tions raised by the religious struggles of the sixteenth
century struck at the very heart of human certainty.
First, non-Christian religions challenged the assurance
people had in the Christian revelation. The revival of,
and admiration for, classical paganism, the impact of
Judaism, thrust into Europe by the expulsion of the
Jews from Spain and Portugal, and the new threat of
Islam in the form of the Turkish invasions of central
Europe, all caused a crisis of confidence in Christianity,
which is reflected, for example, in Jean Bodin's dia-
logue, Colloquium heptalomeres.... In this secret
work (not published until the nineteenth century,
though circulated widely from the late sixteenth cen-
tury) Bodin had adherents of various religions engage
in debate; the Jew and the believer in natural religion
won the debate, as basic criticisms were leveled against
Christianity.

As Europe was being shaken by these non-Christian
challenges, a more shattering development occurred—
the Reformation—which tore the Christian world
asunder. Starting with complaints about Catholic
practices and beliefs, the reformers were quickly forced
to a theoretical level to defend their criticisms. Begin-
ning with Luther's views at the Leipzig Disputation
(1519), a central issue became that of ascertaining how
one gained true religious knowledge. Luther, Calvin,
and Zwingli challenged the traditional church view,
as well as the criteria on which it was based, namely
tradition and papal pronouncements. Instead they
appealed to conscience and personal religious experi-
ence as the bases of religious knowledge.

Catholic spokesmen then pointed out that once the
reformers gave up the traditional criterion of religious
knowledge of the Church, they would end up in a total
skepticism, “a sink of uncertainty and error.” Using
the recently rediscovered texts of Sextus Empiricus
(published in 1562 and 1569), the Catholics contended
that the Protestants would be forced into the old skep-
tical problem of the criterion, that of trying to establish
an unquestionable standard of true knowledge. All the
reformers could offer were their personal religious
opinions, and any attempt to justify these would lead
either to an infinite regress or to circular reasoning.
The reformers, in turn, saw that the same difficulty
could be raised for the Catholics, in that they could
not justify their criterion of authority and also of the
oral and written tradition. The problem of authenti-
cating a criterion applied as well to an old one as to
a new one.

Each side's probing the foundations of its opponent's
position revealed how uncertain each side's views re-
ally were. The debate continued well into the eigh-
teenth century and made skepticism a living issue for
those enmeshed in the religious struggles. As the fight
continued, the issues became more generalized, ques-
tioning whether any knowledge at all was possible, and
whether there were any criteria that could be relied
upon. Gentian Hervet, the editor of the first printing
of Sextus' Adversus mathematicos (1569), proclaimed
that Pyrrhonism was the answer to Calvinism, because
if nothing could be known, then Calvin's doctrines
could not be known either. Skepticism would make
men humble and obedient, and keep them from new-
fangled false doctrines. The Jesuit, Juan Maldonado,
and his disciples, Cardinal Bellarmine, Cardinal Du
Perron, and the Jesuits, Jean Gontery and François
Veron, developed “a machine of war” to devastate the
Protestants by engulfing them in a series of skeptical
problems. Questions were raised as to what book is
the Bible, how one ascertains what it says or means.
The Protestants were forced by the use of skeptical
arguments to rely solely on their private experience,
which they could never prove was not delusory. The
Protestants made the same sort of skeptical attacks on
the Catholics, e.g., Jean La Placette, The Incurable
Scepticism of the Church of Rome (1688), and The Pope
is a Pyrrhonist (1692), by J. A. Turretin. Each side
exposed the raw nerve of the intellectual world, the
bases of human certainty, and provided reasons for
doubting them.

These various factors, the voyages of exploration, the
humanistic revolt, the impact of cabbalistic and
magical doctrines, the rise of the “new science,” the
religious crises, all contributed to creating a general
skeptical crisis in the sixteenth century, by undermin-
ing confidence in the fabric of the intellectual world,
and by raising fundamental questions about the possi-
bility of human knowledge in any area whatsoever. As
this was happening, several thinkers began to present
a new version of classical skepticism as a way of living
in a radically changing world. Starting with Agrippa
von Nettesheim's popular diatribe, The Vanity of the
Sciences (1526), and Gianfrancesco Pico's Examen
vanitatis doctrinae gentium (1520), materials from
Cicero, Diogenes Laërtius, and Sextus were employed
against the prevailing theories of the time. The aim
of this new skeptical attack, however, was not to make
men suspend judgment, but rather to make them aban-
don the quest for knowledge by rational means, and
accept the truth (that is, the true religion) on faith.
Skepticism became the road to faith.

This Christian skepticism, or new Pyrrhonism,
developed primarily as a Catholic position. The classi-
cal statement of this view appeared in Montaigne's
Apology for Raimond Sebond, written mostly in
1575-76, after Montaigne read Sextus, and was under-
going his own personal skeptical crisis. His Apology
purports to “defend” Sebond's rationalist theology by
showing the inadequacy of reason to support any
conclusions about man and the world, and the need
to rely on faith rather than on human capacities for
any intellectual guidance. Modernizing the ancient
skeptical arguments, Montaigne proceeded to under-
mine confidence in the reliability of sense information
and human rational judgments. All of the old routines
about the variability of sense experience, its depend-
ence on various conditions, the inability to find a satis-
factory criterion for judging when it is veridical, etc.,
were woven together into a symphony of doubt. The
crescendo was reached when Montaigne pointed out
that

(Montaigne, Apology for
Raimond Sebond, in Complete Works..., trans. D. Frame,
Stanford [1967], p. 454).

Our judgments, Montaigne insisted, are influenced by
psychological and cultural factors, and every attempt
to know reality turns out to be like trying to clutch
water.

All that we can do, according to Montaigne, is ac-
cept the Pyrrhonian suspension of judgment, and
following the ancient Pyrrhonian advice, live according
to nature and custom, and receive and accept whatever
it pleases God to reveal to us. This fideistic appeal,
a logical non sequitur from Montaigne's skepticism, is
set forth as the only way out of the skeptical crisis.
Montaigne insisted that the skeptic would not become
a Protestant. His mind would remain blank, purged
of false or dubious beliefs, until God revealed the true
religious principles to him. Prior to that moment, cus-
tom would keep him in the old religion.

Though Montaigne professed to be a Catholic, his
skepticism led him to a generally tolerant view towards
all beliefs. He influenced his friend, Henri IV, to adopt
the tolerant policies enunciated in the Edict of Nantes
(1598). Montaigne's personal religious background (his
own family was partly Jewish, partly Catholic, and
partly Protestant), his skeptical criticisms of actual
religious practices and beliefs and of theology, have
led many, especially from the Enlightenment onward,
to see his skepticism not just as an epistemological one,
challenging human knowledge claims, but also as an
irreligious one, challenging belief in Judeo-Christianity.
Whether Montaigne was a genuine Christian, or
whether he was a covert nonbeliever, is still extremely
difficult to determine. He and his followers set forth
a view called “Christian skepticism,” which they
insisted was the same as that presented by Saint Paul
at the beginning of I Corinthians. By and large,
Montaigne's generalized skepticism and his fideism
were accepted by the counter-reformers in France as
a basis for rebutting the new dogmas of Protestantism,
and for accepting the traditional religion on faith.

Montaigne's presentation of Pyrrhonism became the
most popular expression of the intellectual malaise of
the time. This skeptical atmosphere was further rein-
forced by the writings of Montaigne's distant cousin,
Francisco Sanchez, and by those of Montaigne's disci-
ples, Father Pierre Charron and Bishop Jean-Pierre
Camus.

Sanchez, a Portuguese forced convert from Judaism,
professor of philosophy and medicine at Toulouse,
wrote some skeptical works at the same time as
Montaigne's Apology. Using brilliant dialectical skill,
Sanchez attacked the Platonic and Aristotelian theories
of scientific knowledge and concluded that, in a basic
and serious sense, nothing can be known. Then, in
contrast to the destructive conclusion of Montaigne
that one should suspend judgment about the possibility
of gaining knowledge by scientific means, Sanchez
offered a constructive suggestion: all that can be done

is cautious, limited empirical research. This tentative
approach contains the rudiments of a hypothetical
pragmatic science. Sanchez added the fideistic note of
the Christian skeptics as a postscript, faith as the final
answer. Sanchez' version of skepticism had some influ-
ence on seventeenth-century thinkers, and his “con-
structive” skepticism seems to have supplied the sub-
structure of the via media between skepticism and
dogmatism later offered by Pierre Gassendi.

Montaigne's disciple and heir, Father Pierre
Charron, further popularized skepticism. He first wrote
an enormous Counter-Reformation tract, Les trois
vérités (1595), arguing against atheists, non-Christian
religions, and Calvinism, on skeptical grounds. Next
he wrote as a didactic version of Montaigne's Apology,
La sagesse (1601), one of the most widely read books
of the seventeenth century. He advocated rejecting all
opinions and beliefs that are dubious or false, in order
to render the mind blank, ready to receive whatever
God wishes to write upon it. The skeptic, Charron
insisted, cannot be a heretic since, in having no opin-
ions, he cannot have the wrong ones. Until one receives
the Revelation, one should live according to nature
while being skeptical.

A somewhat similar Christian skepticism was set
forth by Jean-Pierre Camus, who later became the
secretary of Saint François de Sales and then Bishop
of Bellay.

In the early seventeenth century, Christian skepti-
cism became an acceptable position amongst Catholic
theologians in France, and the avant-garde view of
many intellectuals in Paris. The so-called libertins
érudits, Gabriel Naudé, secretary to cardinals Mazarin
and Bagno and royal librarian, Guy Patin, rector of
the medical school of the Sorbonne, and François de
La Mothe Le Vayer, teacher of the Dauphin and mem-
ber of the French Academy, popularized and promul-
gated the nouveau pyrrhonisme (sometimes joining it
to a Machiavellism in politics). The brilliant young
scientist and philosopher, Pierre Gassendi, in his first
book, Exercitationes paradoxicae adversus Aristoteleos
(1624), leveled a thoroughgoing skeptical attack on
Aristotelianism and other dogmatic philosophies, end-
ing with the news that “no science is possible, least
of all Aristotle's.”

In the 1620's, especially in France, the new skeptics
had succeeded in undermining confidence in all previ-
ous theories, and in creating a genuine skeptical crisis
in the minds of many intellectuals. The situation be-
came so serious that attacks against the new skepticism
began to appear. Some, like that of Father François
Garasse, S.J., claimed that the new skepticism was
undermining religious belief and practice (and he was
rebuked by the Jansenist leader, l'abbé de Saint-Cyran,
who insisted that Charron's view was the same
orthodoxy that Saint Augustine had set fourth). Others
offered answers based on Aristotle's theories. Francis
Bacon hoped to overcome skepticism by the use of new
instruments. Marin Mersenne and his friend, Gassendi,
offered a constructive resolution to the skeptical crisis,
insisting that while skepticism could not be overcome
on the epistemological level, it could be ignored on
the practical and scientific level. Proposing a pragmatic
and positivistic interpretation of the new science, they
set forth a way of living with complete skepticism on
a theoretical plane, while proceeding to gain hypo-
thetical and useful information about the world
through empirical research and the employment of the
hypotheses of the new physics. Herbert of Cherbury
developed a most elaborate scheme for overcoming
skepticism and arriving at true knowledge. Descartes'
friend, Jean de Silhon, offered a combination of
Aristotelian, Stoic, and pre-Cartesian “Cartesian”
rebuttals to skepticism.

René Descartes was most keenly aware of the prob-
lem and also of the inadequacy of the answers being
proposed by his contemporaries. Either their solutions
failed to come to grips with the problem, or they failed
to yield indubitable and certain knowledge. By the
tactic of pushing skeptical doubts more radically than
his predecessors, Descartes sought to show that skepti-
cism could be overcome, a basis for true knowledge
found, and philosophy and science secured. Employing
the skeptical method of Montaigne and Charron,
Descartes sought to find some truth that could not be
doubted. He rejected all beliefs that might possibly be
false or dubious. He intensified the skeptics' doubt by
raising the possibility that there might be an evil
demon who distorts all human judgments. But in
refutation of all of these doubts, Descartes insisted the
proposition, “I think, therefore I am,” cannot be
questioned. No matter how unreliable our senses and
our judgment are, no matter what the demon is up
to, the cogito must be true, and any attempt to cast
doubt on it reveals its truth. When this truth is
examined to find out why it is indubitable, one dis-
covers the criterion of true knowledge, namely that
whatever is clearly and distinctly perceived is true.
Using the criterion, one can then establish that God
exists, that He is no deceiver, and that He guarantees
that the criterion really is true. With skepticism over-
come, one can then prove that an external world exists
and that through our clear and distinct ideas we can
gain knowledge about it. The Cartesian “way of clear
and distinct ideas” then becomes a means of moving
from doubt to certain knowledge about the world.

Descartes attempted to establish a new philosophy
on the ruins of the skepticism that had engulfed

European thought. His radical innovation in the battle
against skepticism shaped the structure and the prob-
lems of subsequent philosophy. The skeptics of the
period were undaunted by Descartes' alleged conquest
of skepticism, and they set to work to redirect their
argumentation against this new dogmatic theory to
show that Descartes had failed. On the other hand,
Descartes' dogmatic opponents (e.g., Gisbert Voetius,
Martin Schoock, Pierre Bourdin) sought to show that,
his protestations notwithstanding, he still remained a
skeptic, and a most dangerous one.

As soon as Descartes' theory appeared, Father
Bourdin argued that if one could actually entertain the
original doubts of Descartes, one would have under-
mined the possibility of finding an indubitable truth,
since one could not trust one's faculties or one's under-
standing. Mersenne and Gassendi contended that the
truths claimed by Descartes to be certain and indubit-
able, were still in fact open to question, and might
possibly, in some sense, be false. Gassendi and the later
skeptic, Bishop Pierre-Daniel Huet, analyzed and
reanalyzed the cogito to show that it really established
nothing. Gassendi insisted that the whole Cartesian
system might just be a subjective vision of the author's.
Huet claimed that the Cartesian system was just a
collection of ideas and, as ideas, could not represent
reality. Both challenged the criterion of knowledge,
saying that we could only tell what we thought was
clear and distinct, but not what was really in fact, clear
and distinct. The criterion, they insisted, could never
be applied with certainty unless we possessed another
criterion, and so forth. Huet joined forces with Leibniz
and with the Jesuit opponents of Cartesianism, and
leveled all sorts of charges against “the Father of Mod-
ern Philosophy,” seeking to reduce his vaunted
achievement to rubble.

The later Cartesians tried to modify the theory to
meet the critic's objections, and each new modification
was met with a new dogmatic bombardment hammer-
ing away at the uncertainty of the Cartesian system,
and at its inability to build a secure bridge from the
world of ideas to reality. When Malebranche appeared
with his radically revised Cartesianism, designed in
part to meet the skeptical difficulties, the skeptic,
Simon Foucher, and the orthodox Cartesian, Antoine
Arnauld, sought to show that Malebranchism led to
a “most dangerous Pyrrhonism.” Foucher, who tried
in his many writings to revive Academic skepticism,
offered a new skeptical objection that was to play an
important role in the subsequent history of ideas. The
Cartesians, he pointed out, were willing to accept the
skeptical reasonings that showed that the secondary
qualities (color, sound, heat, taste, and smell) were
subjective and not features of reality. The same rea
sonings, Foucher insisted, should lead one to deny that
the primary qualities (extension and motion, the ingre-
dients of the Cartesian real world) were objective, and
hence that none of the qualities we are aware of are
constituents of reality. This argument was used by
Bayle, Berkeley, and Hume as a decisive challenge to
the basic assumptions of the “new philosophy.”

In contrast to the anti-Cartesian skepticism in
France, another kind was developing in England out
of the theological controversies there. In the quest for
the “true” religion, some theologians starting with
William Chillingworth, tried to distinguish between
the kinds of doubts raised by Sextus and Descartes,
which they felt were unanswerable, and reasonable
doubts that common sense and probable information
could deal with. These theologians conceded that we
could not gain absolutely certain knowledge, but, they
insisted, there is some knowledge which cannot be
reasonably doubted. Bishop John Wilkins and the
Reverend Joseph Glanvill, both members of the Royal
Society, presented a distinction between infallibly and
indubitably certain knowledge. The former, because
of skeptical difficulties, cannot be attained by human
beings, but the latter, in terms of the indubitable
beliefs, is accepted by all reasonable men. Using these,
they constructed a theory of empirical science and of
law as a means for finding useful knowledge, and for
deciding human problems within the limits of a “rea-
sonable doubt.” The limited skepticism of Glanvill and
Wilkins developed into the theory of science of the
early Royal Society and the theory of legal evidence
in Anglo-American law. It also provided a basis for
a tolerant latitudinarian Christianity.

John Locke's compromise with skepticism and his
appeal to an intuitive and common sense rejection of
complete doubt derives, in part, from these views.
However, his compromise was immediately attacked
by Bishop Stillingfleet as resulting in another form of
extreme skepticism in his rejection of “substance.”
Stillingfleet saw this as denying that there was any
genuine certainty about the world, and even raising
the possibility of metaphysical skepticism, a doubt
whether there is any reality at all.

Throughout the seventeenth century, the new
theorists felt confronted by skepticism, and in their
attempts to offer new answers tried to overcome the
challenge. Thomas Hobbes, a personal friend of many
of the French skeptics, proposed as the solution to their
problem of finding a criterion for true knowledge, that
it be a political rather than an epistemological matter.
The ruler would decide, and thus settle the skeptical
controversies, taking on himself the risk of being
wrong.

Pascal, who probably felt the force of the new skep-

ticism more than anyone else of the time, presented
a “constructive” skepticism in his scientific writings,
advocating a hypothetical probabilistic science and
mathematics. In the Pensées (1670), he first forcibly
developed the skeptical case, and then insisted that
nature just would not permit one to be in complete
doubt: Le coeur a ses raisons que la raison ne connaît
point (“The heart has its reasons that reason does not
know,” Pensées, #434). We are torn between dogma-
tism and skepticism, belief and doubt. Only by listening
to God, by having mystical experience, can one get be-
yond the skeptical crisis. The solution for Pascal is not
philosophical, but religious.

Spinoza, on the other hand, tried to offer the most
rationalistic resolution. Doubt only occurred because
one lacked knowledge. By attaining clear and adequate
conceptions one overcame all skeptical difficulties. The
clear and adequate conceptions were their own crite-
rion and provided their own guarantee of their cer-
tainty and truth. The proper pursuit of philosophy in
the geometrical manner was the answer to skepticism.

Leibniz, a close friend of the “Academic” skeptics,
Huet, Foucher, and Bayle, wrote many of the basic
statements of his views as answers to them. He believed
that the skeptics had raised important problems, and
that his system of logic, epistemology, and metaphysics
had solved them. For about thirty years he argued with
his skeptical friends. Bayle's article “Rorarius” was the
first extended criticism of Leibniz' theory, and Leibniz'
Theodicy was intended to answer Bayle's skepticism.

Bishop Berkeley also saw his theory as the answer
to the skeptics. By accepting the skeptics' claim that
all that we know are ideas, and then insisting that ideas
are reality, Berkeley believed he had solved the prob-
lem. As he saw it, the seventeenth-century meta-
physicians had created a gulf between appearance and
reality with their insistence that there was a material
reality. This allowed the skeptics to argue that only
appearances were actually known. By amalgamating
things and ideas, and making the world basically spir-
itual, Berkeley believed he had saved the world from
skepticism and irreligion, and had established “the
reality of human knowledge.” And much to the
Bishop's chagrin, for all of his valiant efforts, he was
treated as the wildest of skeptics by his contemporaries.

The new skepticism of the Montaignians created a
continuing skeptical crisis on the epistemological level
which the theories of the great century of metaphysics
tried to overcome. The debate between the new skep-
tics and the new dogmatists shaped the form of the
new theories, and revealed their weaknesses and de-
fects. While these theories of knowledge and meta-
physical systems were being fought over, another form
of skepticism was developing—irreligious skepti
cism—which was also to have a monumental impact
on modern thought. The new skepticism, from
Montaigne to Bishop Huet, professed to being religious,
since it was always coupled with an advocacy of
fideism. All its advocates except the Huguenot Pierre
Bayle were Catholics, using skepticism to attack
reformers and metaphysicians in the name of true
religion. Whether they were sincere or not, they did
not apply their doubts to their religious tradition or
to the supposed content of revelation.

The raising of skeptical doubts about the truth of
Judeo-Christianity seems to have started in the six-
teenth century as indicated by Bodin's dialogue. The
tragic Portuguese Jewish refugee (in the Netherlands),
Uriel Da Costa, started out questioning the truth of
orthodox Judaism, and the immortality of the soul, and
then went on to questioning all religions. He came to
the conclusion that all extant religions were man-made.
He finally proclaimed that one should not be a Jew
or a Christian; one should just be a man. Da Costa
had reached the point of rejecting Judeo-Christianity,
and is probably the first European man to try to live
outside of it. However, his major ideas were unknown
until published posthumously in 1687.

The French courtier, Isaac La Peyrere, a friend of
the leading skeptics of the time, raised a basic skepti-
cism about the Bible in his shocking work, Prae-
Adamitae (1655; trans. as Men Before Adam, 1656).
La Peyrère had become convinced from his reading
of the Bible, and from geographical and anthropologi-
cal evidence about China, the New World, Greenland,
etc.) that there must have been people before Adam,
and that the Bible cannot be an accurate account of
all of human history. He questioned the accuracy of
the biblical texts that we have. Finally he developed
a strange mystical theory that the Bible describes only
Jewish history, that the rest of mankind developed
separately, and that the messianic culmination of
Jewish history was at hand. Needless to say, his book
was immediately suppressed and the author jailed. He
converted from Calvinism to Catholicism, personally
apologized to the Pope, retired to the pious Oratory,
and went on developing his heretical theories.

La Peyrère's bombshell led two scholars of the
Bible, Baruch de Spinoza and Father Richard Simon,
to develop far-reaching skepticisms with regard to
religious knowledge. Spinoza carried on La Peyrère's
doubts, in his Tractatus-theologico-politicus (1670), and
questioned the Mosaic authorship of the Pentateuch,
as well as other biblical claims. Spinoza suggested that
the Bible was not Divine Revelation, but just an early
record of Jewish superstitions and activities. Finally
Spinoza insisted that religion was to be interpreted
naturalistically in psychological and sociological terms.

He had provided a metaphysics for seeing the world
apart from all revelation, and had cast doubt on the
authenticity and seriousness of the purported revealed
texts of Judeo-Christianity.

Father Richard Simon, an associate of La Peyrère's
at the Oratory and a reader of Spinoza, was the greatest
Bible scholar of his age, and, along with Spinoza, the
founder of modern biblical criticism. He set out to
prove that the Protestants could never find an accurate
text of the Bible or discover what it meant. Building
on La Peyrère's and Spinoza's points, he used his
wealth of erudition to create a skepticism with regard
to the message of the Bible. Simon pointed to the
epistemological difficulties in ascertaining any histor-
ical fact, and insisted that all that we knew about the
message were dubious historical claims of human
beings, who in their fallible way had tried to record
the message. Unlike Spinoza, Simon seems to have been
convinced that there is a message, and tried in his own
way to give the best statement of it in his time.

However, when La Peyrère, Spinoza, and Simon
were done with examining the revealed religions, it
was difficult for intellectuals to accept the Bible with
the previous innocence. The possibility had been raised
that the Bible was not true, or only partially true. The
difficulties in assessing the actual text of the Bible had
become insuperable. These new skeptical doubts would
not be resolved by religion, but religion itself had
become a proper subject of skeptical doubting.

The culmination of the many strands of seventeenth-
century skepticism appears in the writings of the
greatest of the seventeenth-century French skeptics,
Pierre Bayle. Bayle, a Protestant, who became a Cath-
olic and then reverted to Protestantism, fled to Rotter-
dam where he wrote against all sorts of religious and
philosophical theories. In his masterpiece Dictionnaire
historique et critique (1697-1702), Bayle surveyed and
skeptically criticized the various facets of the seven-
teenth-century intellectual world. With his brilliant
dialectical skill, Bayle undermined the metaphysical
theories of Descartes, Spinoza, Locke, Malebranche,
and Leibniz, attacked the theologies of his time, ridi-
culed the biblical heroes of the Old Testament,
challenged the criterion of rational knowledge, and
tried to show that the worst heresies like Manichaeism,
were more plausible rationally than Christianity. Every
theory, in Bayle's hands, led to perplexity and
absurdity, and constituted “the high road to Pyrrho-
nism.” And, he insisted, over and over again, all one
could do after seeing the debacle of the rational world
was to abandon reason and turn to faith, pure blind
faith. But Bayle had so ridiculed the usual content of
faith that little seemed left except complete doubt
about the possibility of understanding anything, except
by historically describing it. What Bayle himself be-
lieved, if anything, is almost impossible to discern in
his sea of doubts.

Bayle's Dictionary launched the Age of Reason, by
providing what Voltaire called “The Arsenal of the
Enlightenment.” Bayle had pulled together all the
strains of skepticism and had laid bare all the defects
of the theories of the time, undermining the quest for
any metaphysical or theological certainty.

The eighteenth century began bathed in Baylean
doubts. However, instead of being dismayed by his
shattering skeptical conclusions, eighteenth-century
thinkers were willing to apply Bayle's criticisms to
religion, theology, and metaphysics, but saw a new
way of understanding the universe—Newtonian sci-
ence. Bayle was seen as the summit of wisdom before
Newton, but now there was no longer any reason to
be so dubious, except about religion and metaphysics.

One of the very few who was still concerned with
skepticism was the Scot, David Hume, an avid reader
of Bayle. Hume apparently went through his own
personal skeptical crisis as he wrote his Treatise of
Human Nature (1739). He started off as a Newtonian,
hoping to apply “the experimental method of reason-
ing” to moral subjects. However, as he “scientifically”
examined how people think, he began to develop a
skepticism about man's ability to know anything be-
yond the immediately felt “impressions” or beyond
what was demonstrable from “relations of ideas.”
However, almost all our information about the world
depends on causal reasoning which cannot be justified
logically because we cannot discover any demonstrable
necessary connection between any pair of events called
“cause and effect.” When we examine how we do reach
conclusions about matters of fact beyond immediate
experience, we find such beliefs are based on psycho-
logical habit or custom, rather than on rational evi-
dence. We can describe how we “reason,” but we
cannot justify it by reason. As Hume inquired why
people believe that reason can establish matters of fact
or necessary causes in the external world, in the unity
of the self, and in demonstrations of the existence of
God, he became all the more skeptical. He found that
the empirical evidence should lead to disbelief, the
psychological explanations were inadequate, and his
own explanations were inconsistent, but nonetheless
he, like everyone else, believed what could not be
proved by reasoning. “Philosophy would render us
entirely Pyrrhonian, were not nature too strong for it”
(Hume, Abstract of a Treatise of Human Nature, ed.
L. A. Selby-Bigge, Oxford [1888], p. 24). “Nature, by
an absolute and uncontrollable necessity has determin'd
us to judge as well as to breathe and feel” (Hume,
Treatise, p. 183). Nature did not refute skepticism, but

made it unbelievable enough of the time so that life
could go on. By the time Hume reached the end of
the first book of the Treatise he seemed to see a skepti-
cism as complete as Bayle's. “We have, therefore, no
choice left but betwixt a false reason and none at all.”
“I am ready to reject all belief and reasoning, and can
look upon opinion even as more probable or likely than
another” (Hume, Treatise, pp. 268-69). In this skeptical
despair, reminiscent of Pascal's picture of man without
God, Hume saw salvation only in the beneficent actions
of nature that stop all doubting in time. By living
according to nature, sometimes he was forced to doubt
and sometimes to believe. The beliefs are not based
on evidence, but only on feelings and habits. Any
examination of the beliefs just reveals the skeptical
difficulties, but these difficulties notwithstanding,
everyone including the Humean skeptic, has to believe
all sorts of things.

Hume apparently saw, as no one else in the eight-
eenth century did, the plight of modern man if Bayle's
doubts could not be answered, and if no fideistic or
supernatural solution was acceptable. The new science
of Newton only described what “reasonable” men
believed, operating on normal natural psychological
habits and customs. It did not really tell anybody what
was necessarily true, and its conclusions could never
be satisfactorily justified. No religious faith could any
longer be taken seriously, once the arguments of the
irreligious skeptics were applied to it. Hume could not
calmly survey in Bayle's manner the wreckage wrought
by skepticism. He had to believe, like everyone else,
but he could only see his beliefs based on an unjustified
and unjustifiable animal faith, rather than on a religious
one. The world and life might have no discoverable
meaning, but nature benevolently made us persevere.
And Hume persevered by trying to describe human
nature, man and his foibles, in historical terms. History
became the constructive issue of Hume's skepticism
as it was for Bayle. Historical description would re-
place philosophy as the way of studying man, and
would still further undermine man's pretensions.

Hume's skepticism had little effect on his immediate
contemporaries. They found his historical and political
writings exciting, his irreligious ones immoral or
intriguing, but his skepticism a bore in a Newtonian
age. It was admired by the reactionaries and religious
fanatics in France, but not by the philosophes. After
the Revolution, Joseph de Maistre and Félicité de
Lamennais could appreciate Hume, because his skep-
ticism undermined the new dogmatism of the revolu-
tionaries and the atheists, and they could advocate a
fideism again on the basis of it.

One who saw what Hume had accomplished was
his fellow Scotsman, Thomas Reid. Reid perceived that
Hume, and Berkeley before him, had shown that the
fundamental assumptions of modern philosophy fol-
lowing from the intellectualism of Descartes led to a
total skepticism and distrust of the senses. Reid felt
that a reconsideration of the rationalistic assumptions
which led to so disastrous a result was required. When
philosophy reached conclusions contrary to common
sense, then philosophy must be wrong. Nobody can
be a complete skeptic in belief or action. Therefore
one should start with the beliefs people are unable
psychologically to doubt, such as that there is an exter-
nal world. Common-sense realism, Reid claimed, could
avoid the skeptical pitfalls in the Cartesian and
Lockean theories. Hume replied that Reid had seen
the problem, but his solution was really the same as
Hume's, skepticism cannot be answered on a theoret-
ical level, and nature makes us live and believe.

The Scottish School following Reid was the first to
see that Hume's skepticism was the view to oppose
if philosophy was to continue to make sense of the
world. However, the way developed in Germany of
dealing with Hume's skepticism had the greatest effect
on subsequent philosophy. The leaders of the Prussian
Academy had been concerned with Pyrrhonism, had
translated Hume, and had tried to refute him. Others
had presented modern skeptical views, and had trans-
lated Hume's Scottish critics.

Immanuel Kant read this literature and wrote that
Hume had awakened him from his dogmatic slumbers.
He saw that Hume had challenged the Enlightenment
view that skepticism could be ignored and replaced
by science. The fundamental question, “How is knowl-
edge possible?” now required reexamination.

Kant's answer was to admit a complete skepticism
regarding the possibility of gaining metaphysical
knowledge by pure reason, while insisting that univer-
sal and necessary knowledge about the conditions of
all possible experience could be attained. Starting from
the conviction that some knowledge is possible, Kant
then tried to show how such universal and necessary
information occurs. Kant's revolutionary solution to the
skeptical crisis was that necessary and universal condi-
tions are involved in having any experience and making
any judgments. Through these we can gain some cer-
tain knowledge. Mathematics is the knowledge of the
a priori conditions of experience. And we can also know
certain conditions about how our judgments about
experience are organized.

These conditions apply to the forms of possible
experience and to judgments about them, but do not
tell us about their contents, or about the realities
behind them—the real world, the self, or God. For
Kant the content of experience can only be learned
empirically, and such information could be no more

than probable. We cannot gain any metaphysical
knowledge by pure reason, since there is no way of
telling if our categories apply beyond all possible ex-
perience, or what they then might apply to. However,
by practical reason we act as if certain conditions
prevailed beyond experience.

Kant thought he had ended the age-old struggle with
skepticism. However, some of Kant's contemporaries
saw his accomplishment as just opening the way for
a new skeptical age, rather than resolving the skeptical
crisis. Some saw that the application of his theory to
religion (religion within the limits of bare reason alone)
provided the theoretical grounds for a thoroughgoing
skepticism of all revealed religion.

Kant's critic, G. E. Schulze (also known as Schulze-
Aenesidemus), contended that Kant's philosophy pro-
vided no way for attaining truths about objective real-
ity, or things-in-themselves. All that we could know
was the subjective necessity of some of our views,
which Hume had already pointed out. Hence Kant's
theory was really only a vindication of Hume's kind
of subjective skepticism.

Another thinker, Solomon Maimon (recognized by
Kant as his most astute critic), developed a “rational
skepticism” from within Kant's theory. Maimon
accepted the view that there are a priori concepts, but
held that the application of these categories to experi-
ence was only known inductively and could only yield
probability. Hence no universal and necessary knowl-
edge about experience could be gained. The question
of whether there was such knowledge was, for Maimon,
always an experimental matter, and as Hume had shown,
no final certainty could be gained on this score.

For Maimon there are a priori forms of thought, but
the relation of these to matters of fact remains proble-
matic. Propositions about these a priori concepts were
true because they were about human creations, and
not because they necessarily had any objective
relevance. Maimon's view that human creativity was
the basis of truth was developed by Fichte as a new
means of overcoming skepticism and reaching knowl-
edge of reality.

Kant's friend, the religious fanatic, J. G. Hamann,
took the arguments of Hume and Kant as establishing
that knowledge of reality could not be reached by
rational means. Therefore he advocated an acceptance
of irrational faith as the result of complete skepticism.
Hamann's irrational fideism was later adopted by
Lamennais as an answer to Enlightenment views in
France and a new defense of conservatism and ortho-
doxy, and by Kierkegaard as an answer to Hegelianism
and religious liberalism. Both reacted with extreme
skepticism to the “progressive” intellectual and reli-
gious trends during the early nineteenth century.
Kierkegaard brilliantly exploited the skeptical possi-
bilities against the views of his contemporaries and
insisted on the need for faith, on the unjustified and
unjustifiable “leap into faith,” as the only way to find
subjective rather than objective certainty. The anti-
rational fideism of Hamann, Lamennais, and Kierke-
gaard has been revived by neo-orthodox and existen-
tialist theologians in the twentieth century, arguing
that skepticism reveals our inability to find ultimate
truth by rational means, hence the need for faith and
commitment.

After Kant, although few philosophers call them-
selves skeptics, skepticism has permeated many of the
major movements of thought. The struggles with the
new forms of skepticism from Descartes to Kant had
indicated that normal rational and scientific procedures
were inadequate to gain knowledge about reality, or
to support claims to religious knowledge. For most
subsequent thinkers a kind of partial skepticism was
accepted either as a means of transcending it, or as
a means of living with it. These thinkers can only be
considered as partial skeptics, or users of skepticism
to develop new theories.

The German metaphysicians, starting with Fichte
and Hegel, tried to overcome skepticism by examining
the creative and historically developing intellectual
processes with skepticism as a stage in this. For Fichte
skepticism makes one realize that a fundamental
unjustifiable metaphysical commitment has to be made.
This commitment allows one to see things in terms of
creative thought processes, and to uncover a structure
of the world in which everything is seen as related
to the Absolute Ego.

For the Hegelians, skeptical arguments show how
unintelligible is each limited picture of the world. Since
the universe and our understanding of it is historically
developing, there is a legitimate skepticism at each
stage, in that the world and our understanding of it
are incomplete and contradictory. Until the self-
realization of the Absolute, and our attainment of
knowledge of it, all of our knowledge is only partly
true and partly false. At the final stage, skepticism will
have been overcome and genuine knowledge will be
possible.

The empirical, positivistic, and pragmatic move-
ments of the nineteenth and twentieth centuries that
have combatted German idealistic metaphysics have
by and large adopted a thoroughgoing skepticism about
the possibility of gaining any metaphysical knowledge.
The empiricists and positivists have argued that there
is no means of gaining knowledge beyond empirical
data, except in terms of logical and mathematical
tautologies. Many pragmatists have found the tradi-
tional metaphysical quest meaningless, and meta-

physical assertions unverifiable and useless. The
empiricists, positivists, and pragmatists have tried to
absorb or obviate the skeptical challenge by restricting
the quest for knowledge to the empirical world, or to
mathematics, and accepting explicitly or tacitly a
skepticism about metaphysics. Some, by redefining
knowledge, have in effect adopted a kind of skepticism.

Another type of modern skepticism has developed
from the social sciences. The work of Marx, Nietzsche,
James, Freud, and others, has produced a new form
of relativistic skepticism. If the views people hold are
the products of human culture and behavior, and vary
with social economic and psychological conditions, can
any of these views be considered as true? Nietzsche
and Freud have raised the possibility of value skepti-
cism, that all value beliefs may be man-made, and that
there really are no objective values. Marx indicated
that all views may just be reflections of other develop-
ing factors.

In the twentieth century, when so many of the
strands of modern skepticism have been absorbed into
the main intellectual currents, very few thinkers have
proclaimed themselves skeptics. Many have accepted
a skepticism or semi-skepticism, and then ignored it
and have gone on about their intellectual business.
Some have developed views indicating what remains
after a fundamental skepticism has been adopted, what
sort of sense may still be made of man and his world.

The forms of overt skepticism in this century have
varied greatly, from the naturalistic animal faith vari-
ety of George Santayana, the linguistic positivistic
mystical kind of Fritz Mauthner, the skeptical solipsism
and practical altruism of Adolfo Levi, the extreme
anti-rational skeptical fideism of Lev Shestov (the
Russian Orthodox theologian), the existentialist skepti-
cism, if one can call it that, of Jean Grenier and his
student, the novelist Albert Camus to the semi-
skepticism of Vaihinger, Alain, and Popper. Each of
these thinkers has pointed to the modern malaise,
either in despair or with equanimity, that because of
the reasons raised by the skeptics over the past four
centuries, the modern intellectual era has failed to
achieve the level of intellectual security and certainty
of past ages.

Mauthner's analysis of language indicated the com-
plete relativism and subjectivism of any way of
describing the world, without any means being known
of independently evaluating which, if any of these,
corresponded to reality. Mauthner finally concluded
that all that was possible was a kind of godless mystical
contemplation of the world.

Santayana contended in his brilliant Scepticism and
Animal Faith (1923) that any interpretation of imme
diate or intuited experience was questionable: “Noth-
ing given exists.” However, we do interpret the given
in order to make life meaningful, and interpret it in
terms of an “animal faith.” This is consistent with a
thoroughgoing skepticism, and is pursued by following
natural and social tendencies and inclinations. The
beliefs that result from animal faith enable us to pre-
serve and to appreciate the richness of life.

In contrast, Shestov not only applied a complete
skepticism to rational beliefs, but insisted on a radical
rejection of all rational standards in order to reach
faith. Shestov insisted on the need to reject even math-
ematical truths in order to achieve or make room for
the religious life. For Shestov rationality is contra-
dictory and cosmically dangerous.

Camus, building on Grenier's skepticism, saw man
as trying to decipher the nature and meaning of a
universe that is basically absurd, employing dubious
rational and scientific means. Camus used the skeptical-
fideistic arguments but rejected the religious solution.
Accepting Nietzsche's claim that God is dead, and that
the universe is ultimately meaningless, Camus painted
his protagonists as having to struggle with a world that
is unintelligible and senseless. They have to recognize
and accept the human situation, and find whatever
personal meaning is possible through struggle though
it has no objective or ultimate or rational significance.

Sir Karl Popper's quasi-skepticism, much like that
of the constructive skepticism of Gassendi and of the
scientific Pascal, has sought to dispose of the illusions
that immutably demonstrable truths could be found in
logic, mathematics, and science. He has sought to show
that adequate verification of truths is not possible, and
has tried to offer ways of proceeding in science and
mathematics that can be of value without having to
resolve the basic skeptical difficulties.

All of these who have presented forms of skepticism
in the twentieth century have indicated that the fun-
damental skeptical problems raised in ancient times
and revived in the Renaissance have not been resolved
by modern philosophy, theology, or science. Over the
last four centuries, the skeptics have refurbished the
ancient arguments, and redirected them against the
new dogmatists who have arisen. Renaissance skepti-
cism helped erode confidence in scholastic and Platonic
ways of understanding the universe. The irreligious
skepticism of the seventeenth and eighteenth centuries
made it difficult to accept the Judeo-Christian world
view in an objective and literal sense. The critical
analyses of Bayle, Hume, Kant, and the post-Kantian
critics undermined the new metaphysical ventures of
the seventeenth century. The anti-metaphysical posi-
tivism and the social scientific relativism of the last

two centuries have indicated that it is unlikely that
any final truth will be discovered by human rational
or scientific means.

The struggle against skepticism has been one of the
dynamic factors in the development of modern
thought, urging thinkers to probe for new means of
answering the attacks. The erosion, through the various
forms of modern skepticism, of the structure of Western
European thought has left most contemporary thinkers
unable or unwilling to seek any longer certain and
unshakeable foundations of a system of thought for
understanding man and the universe. Most have
accepted some or many elements of the skeptics' chal-
lenge, and, as a result many philosophers have turned
away from the quest for any ultimate truth or meaning.
Instead they have sought ways of living with the
unresolved skeptical crisis through humanistic, scien-
tific, animal, or religious faiths.

BIBLIOGRAPHY

Don Cameron Allen, Doubt's Boundless Sea: Skepticism
and Faith in the Renaissance (Baltimore, 1964). Samuel
Atlas, From Critical to Speculative Idealism: The Philosophy
of Salomon Maimon (The Hague, 1964). Christian
Bartholmèse, Huet, évêque d'Avranches, ou le scepticisme
théologique (Paris, 1850). George Boas, Dominant Themes
of Modern Philosophy (New York, 1957). Tullio Gregory,
Scetticismo ed empirismo: Studio su Gassendi (Bari, 1961).
Marcellino Menendez Pelayo, Obras completas, Vol. XLIII,
Ensayos de critica filosofica (Santander, 1948), Ch. 2, “De
los origenes del criticismo y del escepticismo y especial-
mente de los precursores españoles de Kant,” pp. 117-216.
Arne Naess, Skepticism (New York, 1969), contains an ex-
tensive bibliography. Charles G. Nauert, Agrippa and the
Crisis of Renaissance Thought (Urbana, 1955). John Owen,
Evening With the Skeptics (London, 1881); idem, The Skep-
tics of the French Renaissance (London and New York, 1893).
Richard H. Popkin, “David Hume: His Pyrrhonism and His
Critique of Pyrrhonism,” Philosophical Quarterly, 1
(1950-51), 385-407; idem, The History of Scepticism From
Erasmus to Descartes (Assen, Netherlands, 1960; New York,
1964, 1968). Contains lengthy bibliography on skepticism
from 1500 to 1650; idem, “Scepticism in the Enlighten-
ment,” in T. Bestermann, ed., Studies on Voltaire and the
18th Century, Vol. XXVI (Geneva, 1963), pp. 1321-45; idem,
“The High Road to Pyrrhonism,” American Philosophical
Quarterly, 2 (1965), 1-15; idem, “Scepticism, Theology and
the Scientific Revolution in the Seventeenth Century,”
Problems in the Philosophy of Science, ed. Lakatos and
Musgrave, Vol. III (Amsterdam 1968), 1-39. Karl Popper,
Conjectures and Refutations, 2nd ed. (New York, 1968).
George Santayana, Scepticism and Animal Faith (New York,
1923; reprint 1955). Charles B. Schmitt, Gianfrancesco Pico
della Mirandola (The Hague, 1967). Henry G. Van Leeuwen,
The Problem of Certainty in English Thought 1630-1690
(The Hague, 1963). Richard A. Watson, The Downfall of
Cartesianism (The Hague, 1966).

RICHARD H. POPKIN

[See also Agnosticism; Authority; Certainty; Faith; Irra-
tionalism; Machiavellism; Positivism; Probability;Refor-
mation; 1">Relativism;Renaissance Humanism.]