Scepticism

(Skepticism)

Skeptics

(Gr. sképsis, speculation, doubt; sképtesthai, to scrutinize or examine carefully)

may mean (1) doubt based on rational grounds, or (2) disbelief based on rational

grounds (cf. Balfour, "Defence of Phil. Doubt", p. 296), or (3) a denial of the

possibility of attaining truth; and in any of these senses it may extend to all

spheres of human knowledge (Universal Scepticism), or to some particular

spheres of the same (Mitigated Scepticism). The third is the strictly philosophical

sense of the term Scepticism, which is taken, unless otherwise specified, to be

universal. Scepticism is then a systematic denial of the capacity of the human

intellect to know anything whatsoever with certainty. It differs from Agnosticism

because the latter denies only the possibility of metaphysics and natural

theology; from Positivism in that Positivism denies that we do de facto know

anything beyond the laws by which phenomena are related to one another; from

Atheism in that the atheist denies only the fact of God's existence, not our

capacity for knowing whether He exists.

HISTORY OF SCEPTICISM

The great religions of the East are for the most part essentially sceptical. They

treat life as one vast illusion, destined some time or other to give place to a state

of nescience, or to be absorbed in the life of the Absolute. But their Scepticism

is a tone of mind rather than a reasoned philosophical doctrine based upon a

critical examination of the human mind or upon a study of the history of human

speculation. If we wish for the latter we must seek it among the philosophies of

ancient Greece. Among the Greeks the earliest form of philosophical speculation

was directed towards an explanation of natural phenomena, and the contradictory

theories which were soon evolved by the prolific genius of the Greek mind,

inevitably led to Scepticism. Heraclitus, Parmenides, Democritus, Empedocles,

Anaxagoras, though differing on other points, one and all came to the conclusion

that the senses, whence they had derived the data upon which their theories

were built, could not be trusted. Accordingly Protagoras and the Sophists

distinguish "appearances" from "reality"; but, finding that no two philosophers

could agree as to the nature of the latter, they pronounced reality unknowable.

The thorough-going Scepticism which resulted is apparent in the three famous

propositions of Gorgias: "Nothing exists"; "If anything did exist it could not be

known"; "If it was known, the knowledge of it would be incommunicable."

The first step towards the refutation of this Scepticism was the Socratic doctrine

of the concept. There can be no science of the particular, said Socrates. Hence,

before any science at all is possible, we must clear up our general notions of

things and come to some agreement in regard to definitions. Plato, adopting this

attitude, but still holding to the view that the senses can give only dóxa (opinion)

and not epistéme (true knowledge), worked out an intellectual theory of the

universe. Aristotle, who followed, rejected Plato's theory, and proposed a very

different one in its place, with the result that another epidemic of Scepticism

succeeded. But Aristotle did more than this. He propounded the doctrine of

intuition or self-evident truth. All things cannot be proved, he said; yet an infinite

regress is impossible. Hence there must be somewhere self-evident principles

which are no mere assumptions, but which underlie the structure of human

knowledge and are presupposed by the very nature of things (Metaph., 1005 b,

1006 a). This doctrine, later on, was to prove one of the chief forces that checked

the destructive onslaught of the Sceptics; for, even if Aristotle's dictum cannot be

proved, it none the less states a fact which to many is itself self-evident. It was

the Stoics who first took "evidence" as the ultimate criterion of truth.

Perceptions, they taught, are valid when they are characterized by enárgeia, i.e.

when their objects are manifest, clear, or obvious. Similarly conceptions and

judgments are valid when we are conscious that in them there is katálepsis an

apprehension of reality. Contemporaneously, however, with Zeno, the founder of

Stoicism, lived Pyrrho the Sceptic (d. about 270 B.C.), who, though he admitted

that we can know "appearance," denied that we can know anything of the reality

that underlies it. Oudèn mâllon -- nothing is more one thing than another.

Contradictory statements, therefore, may both be true. A scepticism so radical

as this, the Stoics argued, is useless for practical life; and this argument bore

fruit. Arcesilaus, founder of the Middle Academy (third century B.C.), though

rejecting the Stoic criterion and affirming that nothing could be known for certain,

nevertheless admitted that some criterion is needed whereby to direct our

actions in practice, and with this in view suggested that we should assent to

what is reasonable (tò eúlogon). For "the reasonable" Carneades, who founded

the Third Academy (second century B.C.), substituted "the probable":

propositions which after careful examination manifest no contradiction, external

or internal, are pithané (probable) kaà aperístatos (secure) kaì perideuméne

(thoroughly tested) (Sextus Empiricus "Adv. Math.", VII, 166). A subsequent

attempt to reconcile conflicting doctrines having proved futile, however, the

Academy lapsed into Pyrrhonism. Ænesidemus sums up the traditional

arguments of the Sceptics under ten heads, which later on (second century A.D.)

were reduced by Sextus Empiricus to five:

1.human judgments and human theories are contradictory;

2.all proof involves an infinite regress;

3.perceptual data are relative both to the percipient and to one another;

4.axioms, or self-evident truths, are really assumptions;

5.all syllogistic reasoning involves diállelos (a vicious circle), for the major

premise can be proved only by complete induction, and the possibility of

complete induction supposes the truth of the conclusion (Sextus Emp.,

"Hyp. Pyrrh.", I, 164; II, 134; Diogenes Laertius, IX, 88).

From Scepticism the neo-Platonists sought refuge in the immediacy of a mystic

experience; Augustine and Anselm in faith which in supernatural matters must

precede both experience and knowledge (cf. Augustine, "De vera relig.", xxiv,

xxv; "De util. cred.", ix; Anselm, "De fid. Trin.", ii); St. Thomas and the

Scholastics in a rational, coherent, and systematic theory of the ultimate nature

of things, based on self-evident truths but consistent also with the facts of

experience, and consistent too with the truth of revelation, which thus serves to

confirm what we have already discovered by the light of natural reason. But with

the Renaissance, characterized as it was by an indiscriminate enthusiasm for all

forms of Greek thought, it was only natural that the Scepticism of the Greeks

should be revived. In this movement Montaigne (d. 1592), Charron (d. 1603),

Sanchez (d. 1632), Pascal (d. 1662), Sorbière (d. 1670), Le Vayer (d. 1672),

Hirnhaym (d. 1679), Foucher (d. 1696), Bayle (d. 1706), Huet (d. 1721), all took

part. Its aim was to discredit reason on the old grounds of contradiction and of

the impossibility of proving anything. Huet, Bishop of Avranches, and others

sought to argue from the bankruptcy of reason to the necessity and sufficiency of

faith. But for the most part, faith, understood in the Catholic sense of belief in a

system of revealed doctrines capable of intelligent expression and rational

interpretation, so far from being exempt from the attacks of the Sceptics, was

rather (as it still is) the chief object against which their efforts were directed.

Faith, as they understood it, was blind and unreasoning. The diversity of doctrine

introduced by Protestantism had rendered all other faith, in their view no less

contradictory than philosophy and natural belief.

In Hume Scepticism finds a new argument derived from the psychology of Locke.

A critical examination of human cognition, it was said, reveals the fact that the

data of knowledge consist merely of impressions -- distinct, successive,

discreet. These the mind connects in various ways, and these ways of

connecting things become habitual. Thus the principle of causality, the

propositions of arithmetic, geometry, and algebra, physical laws, etc., in short all

forms of synthesis and relations are subjective in origin. They have no objective

validity, and their alleged "necessity" is but a psychological feeling arising from

the force of habit. We undoubtedly believe in real things and real causes; but this

is merely because we have grown accustomed so to group and connect our

mental impressions. The arguments of Pyrrho and other Sceptics are

unanswerable, their Scepticism reasonable and well-founded; but in practical life

it is too much trouble to think otherwise than we do think, and we could not get

on if we did. Kant's answer to Hume was embodied in a philosophy as eminently

subjective as that of Hume himself. Consequently it failed, and resulted only in

further Scepticism, implicit, if not actually professed. And nowadays physical

science, which in Kant's time alone held its own against the inroads of

Scepticism, is as thoroughly permeated with it as the rest of our beliefs. One

instance must suffice -- that of Mr. A. J. Balfour, who in his "Defense of

Philosophic Doubt" seeks to uphold religious belief on the equivocal ground that

it is no less certain than scientific theory and method. There is, he says,

no satisfactory means of inferring the general from the particular (c. ii),

no empirical proof of the law of causality (c. iii),

no adequate guarantee of the uniformity of nature and the persistence of

physical law (cc. iv, v).

Again, of the popular philosophic arguments which are "put forward as final and

conclusive grounds of belief" p. 138), the argument from general consent is not

ultimate; that from success in practice, though it gives us grounds for confidence

in the future, cannot be conclusive, since it is empirical in character; whilst the

argument from common sense which affirms that the intellect, when working

normally, is trustworthy, involves a vicious circle, since normal workings can be

distinguished from abnormal only on the ground that they lead to truth (c. vii).

Similarly the original "deliverances of consciousness", to which Scottish

Intuitionists appeal, are of no avail because it is impossible to determine what

deliverances of consciousness are original and what are not. Returning to the

question of science, Mr. Balfour finds that it contradicts common sense in that

(e.g.) it declares bodies, which appear coloured to our senses, to be made up in

reality of uncoloured particles, and, while thus discrediting the trustworthiness of

observation, provides no criterion whereby to distinguish observations which are

trustworthy from those which are not. Its method, too, is inconclusive, for there

may always be other hypotheses which would explain the facts equally well (c.

xii). Lastly the evolution of belief tends wholly to discredit its validity, for our

beliefs are largely determined by non-rational causes, and, even when evidence

is their motive, what we regard as evidence is settled by circumstances

altogether beyond our control (c. xiii).

CRITICAL EXAMINATION OF SCEPTICISM

A reply to the copious arguments of the Sceptic enumerated above, might take

the following line:

The Sceptic fails to distinguish between practical moral certainty which

excludes all reasonable grounds for doubt, and absolute certainty which

excludes all possible grounds for doubt. The latter can be had only when

evidence is complete, proof wholly adequate, obvious, and conclusive, and

when all difficulties and objections can be completely solved. In

mathematics this is sometimes possible, though not always; but in other

matters "practical certainty" as a rule is all we can get. And this is

sufficient, since "practical certainty" is certainty for reasonable beings.

Axiomatic, or self-evident, truth must be insisted on. The truth of an axiom

can never be proved, yet may become manifest, even to those who for the

time being doubt it, when its meaning and its application are clearly

understood.

Perceptual judgments refer qualities (not sensations) to things, but they

do not declare what is the nature of these qualities, and hence do not

contradict scientific theory.

Perception is trustworthy in that it reveals to us the general character and

behaviour of things -- both of ourselves and of external objects. We do not

often mistake a spade for a table-knife or a turkey for a hippopotamus.

The senses do not pretend to be accurate in detail (unless assisted by

instruments) or in abnormal circumstances.

The "normal" working of our faculties can be determined independently of

any question as to the truth of their deliverances. The work of our faculties

is "normal", (1) when they are free from the influence of subjective factors,

other than those which belong to their proper nature (i.e. free from

disease, impediment, the influence of prejudice, expectancy desire, etc.),

and (2) when they are exercised upon their own proper objects. In the

case of the senses this means upon objects we meet with day by day

under ordinary circumstances. If the circumstances are extraordinary, our

senses are still trustworthy, however, provided the circumstances be

taken into account.

Alleged contradictions inherent in philosophical terms are due to

ambiguity, misunderstanding, the lack of precise definition, or the

influence of a false philosophy. For instance, the contradictions which Mr.

Bradley points out (Appearance and Reality, bk. I) in terms such as time,

spacers substance and accident, causality, self, are not to be found in

these terms as defined by the Scholastics.

Contradictions between different philosophical theories may be (a)

accounted for, and (b) eliminated. (a) They arise from ambiguity, variety of

definition, misconception, misinterpretation, careless inference,

groundless assumption, unverified hypothesis, and the neglect of relevant

facts. Yet (b) all error contains an element of truth, and contradictions

suppose a common principle already granted anterior to their divergence;

and these underlying principles and elements of truth contained in all

theories can be distinguished from the errors in which they are wrapped

up.

Beliefs arising from non-rational or from unknown grounds should either be

re-established on rational grounds or discarded. All beliefs should be

evident either (1) immediately, as in the case (e.g.) of our belief in external

reality, or (2) mediately by inference from known truth, or (3) on the ground

of adequate testimony.

The Sceptic assumes the capacity of the intellect to criticize the faculty of

knowledge, and thus, in so far as he denies its capacity to know anything,

implicitly contradicts himself.

Leslie J. Walker

Transcribed by Rick McCarty

The Catholic Encyclopedia, Volume XIII

Nihil Obstat, February 1, 1912. Remy Lafort, D.D., Censor

Imprimatur. +John Cardinal Farley, Archbishop of New York

The Catholic Encyclopedia: NewAdvent.org