SCEPTICISM signifies etymologically a state of doubt or indecision in the face of different mutually conflicting statements (______, I consider, reflect, hesitate, doubt). It is implied, moreover, that this doubt is not merely a stage in the road to certainty and true knowledge. The provisional suspense of judgment recommended by Descartes and others as the true beginning of philosophy is no more than a passing phase of the individual's mind in his search for truth. But the doubt of the sceptic is professedly the last result of investigation; it is the renunciation of the search for truth on the ground that truth or real knowledge is unattainable by man. An account of the chief historical appearances of scepticism and its different motives will serve to illustrate and amplify this statement, and will lead up to any further considera-tions of a general nature. At the outset, and in general terms, scepticism may be summarily defined as a thoroughgoing impeachment of man's power to knowas a denial of the possibility of objective knowledge.
Trust, not distrust, is the primitive attitude of the mind. Histori-What is put before us, whether by the senses or by the oal aP-statements of others, is instinctively accepted as a veracious Pearances> report, till experience has proved the possibility of decep-tion. In the history of philosophy, in the same way, affirmation precedes negation; dogmatism goes before scepticism. And this must be so, because the dogmatic systems are, as it were, the food of scepticism; without them it would be without motive, without a basis oper-andi. Accordingly, we find that sceptical thought did not make its appearance till a succession of positive theories as to the nature of the real, by their mutual incon-sistency, had suggested the possibility that they might all alike be false. The Sophistic epoch of Greek philo- The sophy was, in great part, such a negative reaction against Sophistc. the luxuriance of self-confident assertion in the nature-philosophies of the preceding age. Though scepticism as a definite school of opinion may be said, in accordance with old precedent, to date only from the time of Pyrrho of Elis, there can be no doubt that the main currents of Sophistic thought were sceptical in the wider sense of that term. The Sophists were the first in Greece to dissolve knowledge into individual and momentary opinion (Prota-goras), or dialectically to deny the possibility of know-ledge (Gorgias). In these two examples we see how the weapons forged by the dogmatic philosophers to assist in the establishment of their own theses are sceptically turned against philosophy in general. As every attempt to rationalize nature implies a certain process of criticism and interpretation to which the data of sense are subjected, and in which they are, as it were, transcended, the anti-thesis of reason and sense is formulated early in the history of speculation. The opposition, being taken as absolute, implies the impeachment of the veracity of the senses in the interest of the rational truth proclaimed by the philosophers in question. Among the pre-Socratic nature-philosophers of Greece, Heraclitus and the Eleatics are the chief representatives of this polemic against the " lying witness " of the senses. The diametrical opposi-tion of the grounds on which the veracity of the senses is impugned by the two philosophies (viz., by Heraclitus because they testify to an apparent permanence and identity in things, by the'Eleatics because they testify to an apparent multiplicity and change) was in itself sugges-tive of sceptical reflexion. Moreover, although these philosophers are not in any sense themselves sceptical, their arguments are. easily susceptible of a wider application. Accordingly we find that the arguments by which Heraclitus supported his theory of the universal flux are employed by Protagoras to undermine the possibility of objective truth, by dissolving all knowledge into the momentary sensation or persuasion of the individual. The idea of an objective flux, or law of change constituting the reality of things, is abandoned, and subjective points of sense alone remain, which is tantamount to eliminating the real from human knowledge.
Still more unequivocal was the sceptical nihilism ex-pressed by Gorgias in his three celebrated theses :(1) nothing exists; (2) if anything existed, it would be un-knowable ; (3) if anything existed and were knowable, the knowledge of it could not be communicated. The arguments of his book, " Concerning the Non-existent, or Nature," were drawn from the dialectic which the Eleatics had directed against the existence of the phenomenal world. But they are no longer used as indirect proofs of a universe of pure and unitary Being. The prominence given by most of the Sophists to rhetoric, their cultiva-tion of a subjective readiness as the essential equipment for life, their substitution of persuasion for conviction, all mark the sceptical undertone of their teaching. This attitude of indifference to real knowledge passed in the younger and less reputable generation into a corroding moral scepticism which recognized no good but pleasure and no right but might.
What Socrates chiefly did was to recreate the instinct for truth and the belief in the possibility of its attain-ment. The scientific impulse thus communicated was sufficient to drive scepticism into the background during the great age of Greek philosophy (i.e., the hundred years preceding Aristotle's death, 323 B.C.). The captious logic of the Megaric school,in which the Eleatic in-fluence was strong,their devotion to eristic and the elab-oration of fallacies, was indeed in some cases closely related to sceptical results. The school has been considered with some truth to form a connecting link with the later scepticism, just as the contemporary Cynicism and Cyrenaicism may be held to be imperfect preludes to Stoicism and Epicureanism. The extreme nominalism of some of the Cynics also, who denied the possibility of any but identical judgments, must be similarly regarded as a solvent of knowledge. But with the^ insignificant exceptions it holds true that, after the scepf JRI wave marked by the Sophists, scepticism does not reappear till after the exhaustion of the Socratic impulse in Aristotle.
The first man in antiquity whose scepticism gave name to his doctrine was Pyrrho of Elis (about 360-270 B.C.). Pyrrho. Pyrrho proceeded with the army of Alexander the Great as far as India, in the company of Anaxarchus, the Democritean philosopher. He afterwards returned to his native city, where he lived in poor circumstances, but; highly honoured by his fellow-citizens. Pyrrho himself left no writings, and the accounts of his doctrine are mainly derived from his pupil Timon of Phlius (about 325-235 B.C.). Timon is called the Sillographist, from his satirical poem (StAAot), in which all the philosophers of Greece are held up to ridicule, with the exception of Xenophanes, who honestly sought, and Pyrrho, who succeeded in finding, the truth. Other disciples are mentioned besides Timon, but the school was short-lived, its place being presently taken by the more moderate and cultured doubt of the New Academy. Zeller sums up Pyrrho's teaching in three propositions:We know nothing about the nature of things; hence the right attitude towards them is to withhold judgment; the necessary result of withholding judgment is imperturbability. The technical language of the school expresses the first position by the word aKaraXruj/La; things are wholly incomprehensible or inaccessible; against every statement the opposite may be advanced with equal justice (to-oo-tfeVeia TU*V Xoywv). The sceptical watchword which embodies the second position is CT-O;^, reserve of judgment, or, as it is put by Timon, oiftkv JU.SXA.OV, that is, no one assertion is truer than another. This complete suspense of opinion is also expressed by the terms appeij/la, or equilibrium, arid arjxuria, or refusal to speak, as well as by other expressions. The Pyrrhonists were consistent enough to extend their doubt even to their own principle of doubt. They thus attempted to make their scepticism universal, and to escape the reproach of basing it upon a fresh dogmatism. Mental imperturbability (arapa^ta) was the result to be attained by cultivating such a frame of mind, The happiness or satisfaction of the individual was the end which dominated this scepticism as well as the contemporary systems of Stoicism and Epicureanism, and all three philosophies place it in tranquillity or self-centred indif-ference. Scepticism withdraws the individual completely into himself from a world of which he can know nothing. It is men's opinions or unwarranted judgments about things, say the sceptics, which betray them into desire, and painful effort, and disappointment. From all this a man is delivered who abstains from judging one state to be preferable to another. But, as complete inactivity would have been synonymous with death, it appears to have been admitted that the sceptic, while retaining his consciousness of the complete uncertainty enveloping every step, might follow custom in the ordinary affairs of life.
The scepticism of the New Academy (or, to speak more Scepti-strictly, of the Middle Academy, under Arcesilaus and cism of Carneades, founders respectively of the so-called second ^e , and third Academies) differed very little from that of the Pyrrhonists. The differences asserted by later writers are not borne out on investigation. But the attitude main-tained by the Academics was chiefly that of a negative criticism of the views of others, in particular of the some-what crude and imperious dogmatism of the Stoics. They also, in the absence of certainty, allowed a large scope to probability as a motive to action, and defended their doctrine on this point with greater care and skill. The whole position was stated with more urbanity and cul-ture, and was supported, by Carneades in particular, by argumentation at once more copious and more acute. It seems also true that the Academics were less overborne than the Pyrrhonists by the practical issue of their doubts (imperturbability); their interest was more purely intel-lectual, and they had something of the old delight in mental exercitation for its own sake. Arcesilas or Arcesi- Arcesilaus (about 315-240 B.C.) made the Stoic theory of laus. irresistible impressions (cpavTarrlou KaTaXyjirri-KaC) the special object of his attack. Mere irresistibleness (faiToAiji/us), he maintained, is no criterion of truth, since false perceptions may equally possess this power to sway the mind. He seems chiefly to have supported his position by adducing the already well-known arguments of former philosophers against the veracity of the senses, and he evidently held that by these arguments the possibility of knowledge in general was sufficiently subverted. We can know nothing, he concluded,not even this itself, that we know nothing. He denied that the want of knowledge reduces us to inaction. Notions influence the will immediately, apart from the question of their truth, and, in all questions of conduct, probability (TO evXoyov) is our sufficient guide, as it is our highest attainable standard. It is stated that Arcesilaus made his negative criticism merely a preliminary to the inculcation of a modified Platonism. But this account, though not in itself incredible, is not borne out by any evidence at our Car- disposal. The theory of Carneades (213-129 B.C.) repre-neades. sents the highest development of Academic scepticism. The dogmatic system which Carneades had in view was that of Chrysippus, the Stoic, whose main positions, whether in the theory of knowledge, in morals, or in theology, he subjected to an acute and thorough-going criticism. As to the criterion of truth, Carneades denied that this could be found in any impression, as such; for in order to prove its truth an impression must testify, not only to itself, but also to the objects causing it. We find, however, admittedly, that in many cases we are deceived by our impressions; and, if this is so, there is no kind of impression which can be regarded as guaranteeing its own truth. According to his own examples, it is impossible to distinguish objects so much alike as is one egg to another ; at a certain distance the painted surface seems raised, and a square tower seems round; an oar in water seems broken, and the neck-plumage of a pigeon assumes different colours in the sun; objects on the shore seem moving as we pass by, and so forth. The same applies, he argued, to purely intellectual ideas. Many fallacies cannot be solved, and we cannot, for example, draw any absolute distinction between much and little, or, in short, between any quantitative differences. Our impressions, therefore, furnish us with no test of truth, and we can derive no aid from the operations of the understanding, which are purely formal, combining and separating ideas without giving any insight into their validity. Besides this general criticism of knowledge, Carneades attacked the cardinal doctrines of the Stoic school,their doctrine of God and their proof of divine providence from the evidences of design in the arrangements of the universe. Many of his arguments are preserved to us in Cicero's Academics and De Natura Deorum. His criticism of the contradictions involved in the Stoic idea of God really constitutes the first discussion in ancient times of the personality of God, and the difficulty of combining in one conception the characters of infinity and individuality. As a positive offset against his scepticism, Carneades elaborated more fully the Academic theory of probability, for which he employed the terms 2/x<£ao-i.s and iriflavoT^s. Being necessarily ignorant of the relation of ideas to the objects they represent, we are reduced to judging them by their iMjtion to ourselves, i.e., by their greater or less clearness and appearance of truth. Though always falling short of knowledge, this appearance of truth may be strong enough to determine us to action. Carneades recog-nized three degrees of probability. The first or lowest is where our impression of the truthfulness of an idea is derived simply from the idea itself ; the second degree is where that impression is confirmed by the agreement of related ideas; if a careful investigation of all the individual ideas bears out the same conclusion, we have the third and highest degree of probability. In the first case, an idea is called probable (mOavy); in the second, probable and undisputed (iriOavr¡ KOI oVirepto-7rao-Tos); in the third, probable, undisputed, and tested (Tri6avr¡ KOL airepioTraoTOS KOI 7repi<i¡$¤v¡j.év7j). The scepticism of Carneades was expounded by his. successor Clitomachus, but the Academy was soon afterwards (in the so-called fourth and fifth Academies) invaded by the Eclecticism which about that time began to obliterate the distinctions of philosophical doctrine which had hitherto separated the schools. Cicero also, who in many respects was strongly attracted by the Academic scepticism, finally took refuge in a species of Eclecticism based upon a doctrine of innate ideas, and on the argument from the consensus gentium.
The later scepticismwhich is sometimes spoken of as Later the third sceptical schoolclaimed to be a continuation of scepti-the earlier Pyrrhonism. yEnesidemus, though not abso- °?t lutely the first to renew this doctrine, is the first of whose doctrine anything is known. He appears to have taught in Alexandria about the beginning of the Christian era. Among the successors of iEnesidemus, the chief names are those of Agrippa, whose dates cannot be determined, and the physician Sextus Empiricus (about 200 A.D.), whose Pyrrhonic Hypotyposes, and his work Adversus Matliematicos, constitute a vast armoury of the weapons of ancient scepticism. They are of the utmost value as an historical record. With Saturninus, the pupil of Sextus, and Favorinus, the grammarian, ancient scepticism may be said to disappear from history. What speculative power remained was turned entirely into Neoplatonic channels. To iEnesidemus belongs the first enumeration of the ten so-called tropes (rpoVoi), or modes of sceptical Sceptical argument, though the eifguments themselves were, of tropes, course, current before his time. The first trope appeals to the different constitution of different animals as involving different modes of perception; the second applies the same argument to the individual differences which are found among men; the third insists on the way in which the senses contradict one another, and suggests that an endowment with more numerous senses would lead to a different report as to the nature of things; the fourth argues from the variability of our physical state and mental moods; the fifth brings forward the diversities of appearance due to the position and distance of objects; the sixth calls attention to the fact that we know nothing directly, but only through some medium, such as air or moisture, whose influence on the process cannot be elimi-nated ; the seventh refers to the changes which the sup-posed object undergoes in quantity, temperature, colour, motion, &c.; the eighth really sums up the thought which underlies the whole series, when it argues from the rela-tivity of all our perceptions and notions; the ninth points out the dependence of our impressions on custom, the new and strange impressing us much more vividly than the customary; the tenth adduces the diversity of customs, manners, laws, doctrines, and opinions among men. iEnesidemus likewise attacked the notion of cause at considerable length, but neither in his arguments nor in the numerous objections brought against the notion by Sextus Empiricus do we meet with the thought which furnished the nerve of modern scepticism in Hume. The practical result of his scepticism Aenesidemus sought, like the Pyrrhonists, in arapa^ta. He is somewhat strangely said to have combined his scepticism with a revival of the philosophy of Heraclitus; but the assertion perhaps rests, as Zeller contends, on a confusion. To Agrippa is attri-buted the reduction of the sceptical tropes to five. Of these, the first is based on the discrepancy of human opinions; the second on the fact that every proof itself requires to be proved, which implies a regressus in infinitum ; the third on the relativity of our knowledge, which varies according to the constitution of the percipient and the circumstances in which he perceives. The fourth is really a completion of the second, and forbids the assumption of unproven propositions as the premises of an argument. It is aimed at the dogmatists, who, in order to avoid the regressus in infinitum, set out from some principle illegitimately assumed. The fifth seeks to show that reasoning is essentially of the nature of a circulus in pro-bando, inasmuch as the principle adduced in proof requires itself to be supported by that which it is called in to prove. The attack made in several of these five tropes upon the possibility of demonstration marks this enumeration as distinctly superior to the first, which consists in the main of arguments derived from the fallibility of the senses. The new point of view is maintained in the two tropes which were the result of a further attempt at generaliza-tion. Nothing is self-evident, says the first of these tropes, for, if all things were certain of themselves, men would not differ as they do. Nor can anything be made certain by proof, says the second, because we must either arrive in the process at something self-evident, which is impossible, as has just been said, or we must involve ourselves in an endless regress.
When we review the history of ancient thought, we find, as Zeller puts it, that "the general result of all sceptical inquiries lies in the proposition that every asser-tion may be opposed by another, and every reason by reasons equally strongin the Icroo-diveia TZV \oymv. Or, as the same thing may be expressed, what all sceptical Com- proofs come back to is the relativity of all our ideas. We parison of can never know the nature of things as they are, but and'6"* always only the manner in which they appear to us. The modern criterion of the sceptic is the appearance. Not even his scepti- own proof can claim truth and universal validity : he does cism. not assert; he only seeks to relate how a thing strikes him at the present moment. And even when he expresses his doubts in the form of universal statements they are intended to be included in the general uncertainty of knowledge" (Phil. d. Griechen, iii. 2, p. 58). Both Zeller and Hegel, it may be added, remark upon the difference between the calm of ancient scepticism and the perturbed state of mind evinced by many modern sceptics. Universal doubt was the instrument which the sceptics of antiquity recommended for the attainment of complete peace of mind ; rest and satisfaction can be attained, they say, in no other way. By the moderns, on the other hand, doubt is portrayed, for the most part, as a state of unrest and painful yearning. Even Hume, in various noteworthy passages of his Treatise, speaks of himself as recovering cheerfulness and mental tone only by forgetful-ness of his own arguments. His state of universal doubt, so far from being painted as a desirable goal, is described by him as a " malady " or as " philosophical melancholy and delirium." The difference might easily be interpreted either as a sign of sentimental weakness on the part of the moderns or as a proof of the limitation of the ancient sceptics which rendered them more easily satisfied in the absence of ti It seems to prove, at all events, that the ancient sceptics were more thoroughly convinced than their modern successors of the reasonableness of their own attitude. But whether the ancients were the better or the worse sceptics on that account is a nice question which need not be decided here. It may be doubted, however, whether the thoroughgoing philosophical scepti-cism of antiquity has any exact parallel in modern times, with the single exception possibly of Hume's Treatise on Human Nature. It is true we find many thinkers who deny the competency of reason when it ventures in any way beyond the sphere of experience, and such men are not unfrequently called sceptics. This is the sense in which Kant often uses the term, and the usage is adopted by others,'for example, in the following definition from Ueberweg's History of Philosophy :" The principle of scepticism is universal doubt, or at least doubt with regard to the validity of all judgments respecting that which lies beyond the range of experience." The last characteristic, however, is not enough to constitute scepticism, in the sense in which it is exemplified in the ancient sceptics. Scepticism, to be complete, must hold that even within experience we do not rationally conclude but are irration-ally induced to believe. " In all the incidents of life," as Hume puts it, " we ought still to preserve our scepticism. If we believe that fire warms, or water refreshes, 'tis only because it costs us too much pains to think otherwise" (Treatise, bk. i. iv. 7). This tone, which fairly represents the attitude of ancient sceptics, is rare among the moderns, at least among those who are professed philosophers. It is more easily matched in the unsystematic utterances of a man of the world like Montaigne.
One form of scepticism, however, may be claimed as an exclusively modern growth, namely, philosophical scepticism in the interests of theological faith. These j"t^gt sceptics are primarily Apologists. Their scepticism is not 0f f&\^ " de bonne foy " ; it is simply a means to the attainment of a further end. They find that the dogmas of their church have often been attacked in the name of reason, and it may be that some of the objections urged have proved hard to rebut. Accordingly, in an access of pious rage, as it were, they turn upon reason to rend her. They deny her claim to pronounce upon such matters ; they go further, and dispute her prerogative altogether. They endeavour to show that shefs in contradiction with her-self, even on matters non-theological, and that everywhere this much vaunted reason of man (la superbe raison) is the creature of custom and circumstance. Thus the "im-becility " of reason becomes their warrant for the reception by another organby faithof that to which reason had raised objections. The Greeks had no temptation to divide man in two in this fashion. When they were sceptics, their scepticism had no ulterior motives; it was an end in itself. But this line of argument was latent in Christian thought from the time when St Paul spoke of the " foolishness" of preaching. Tertullian fiercely re-echoed the sentiment in his polemic against the philo-sophers of antiquity :" Crucifixus est Dei Alius ; non pudet, quia pudendum est. Et mortuus est Dei filius; prorsus credibile est, quia ineptum est. Et sepultus resurrexit; certum est, quia impossibile est." But, as Christianity became firmly established, Christian writers1 became more tolerant of speculation; and, instead of flaunting the irreconcileable opposition of reason and dogma, they laboured to reduce the doctrines of the church to a rational system. This was the long task essayed by Scholasticism; and, though the great Schoolmen of the 13th century refrained from attempting to rationalize such doctrines as the Trinity and the Incarnation, they were far from considering them as essentially opposed to reason. Theory It was not till towards the close of the Middle Ages °f^ld rï13^ a sense °f conflict between reason and revelation nature became widely prevalent and took shape in the essentially of truth, sceptical theory of the twofold nature of truth. Philo-sophical truth, as deduced from the teaching of Aristotle, it was said, directly contradicts the teaching of the church, which determines truth in theology ; but the contradiction leaves the authority of the latter unimpaired in its own sphere. It is difficult to believe that this doctrine was ever put forward sincerely ; in the most of those who professed it, it was certainly no more than a veil by which they sought to cover their heterodoxy and evade its consequences. Rightly divining as much, the church condemned the doctrine as early as 1276. Nevertheless it was openly professed during the period of the break up of Scholastic Aristotelianism. Pomponatius, the Alex-andrist of Padua (ob. 1525), was one of its best known advocates.
Pascal. The typical and by far the greatest example of the Christian sceptic is Pascal (1623-1662). The form of the Pensées forbids the attempt to evolve from their detached utterances a completely coherent system. For, though he declares at times "Le pyrrhonisme est le vrai," "Se moquer de la philosophie c'est vraiment philosopher," or, again, " Humiliez-vous, raison impuissante, taisez-vous, nature imbécile," other passages might be quoted in which he assumes the validity of reason within its own sphere. But what he everywhere emphatically denies is the possibility of reaching by the unassisted reason a satisfactory theory of things. The contradictions which meet us everywhere are summed up and concentrated in the nature of man. Man is a hopeless enigma to himself, till he sees himself in the light of revelation as a fallen creature. The fall alone explains at once the nobleness and the meanness of humanity ; Jesus Christ is the only solution in which the baffled reason can rest. These are the two points on which Pascal's thought turns. " There is nothing which is more shocking to our reason " than the doctrine of original sin ; yet, in his own words, "le nud de notre condition prend ses replis et ses tours dans cet abîme; de sorte que l'homme est plus inconcevable sans ce mystère que ce mystère n'est incon-cevable à l'homme." Far, therefore, from being able to sit in judgment upon the mysteries of the faith, reason is unable to solve its own contradictions without aid from a higher source. In a somewhat similar fashion, in the present century, Lamennais (in the first stage of his speculations, represented by the Essai sur l'Indifférence en Matière Religieuse, 1817-21) endeavoured to destroy all rational certitude in order to establish the principle of authority; and the same profound distrust of the power of the natural reason to arrive at truth is exemplified (though the allegation has been denied by the author) in the writings of Cardinal Newman. In a different direction and on a larger scale, Hamilton's philosophy of the con-ditioned may be quoted as an example of the same religious scepticism. Arguing from certain antinomies, said to be inherent in reason as such, Hamilton sought to found theology (in great part at least) upon our nescience, and to substitute belief for knowledge. He also imitated Pascal at times in dilating upon the " impotence " and " imbecility " of our faculties ; but, as with Pascal, this was rather in reference to their incapacitj- to evolve an
" absolute" system t^jfn to their veracity in the ordinary details of experienceT The theological application and development of Hamilton's arguments in Mansel's Bampton Lectures On the Limits of Religious Thought marked a still more determined attack, in the interests of theology, upon the competency of reason.
Scepticism in the ____ centuries
Passing from this particular vein of sceptical or semi-sceptical thought, we find, as we should expect, that the downfall of Scholasticism, and the conflict of philosophical theories and religious confessions which ensued, gave a decided impetus to sceptical reflexion. One of the earliest instances of this spirit is afforded by the book of Agrippa of Nettesheim (1487-1535), De Incertitudine et Vanitate . Scientiarum. Sceptical reflexion rather than systematic scepticism is what meets us in Michel de Montaigne (1533-1592), though the elaborate presentation of sceptical and relativistic arguments in his "Apologie de Raimond Sebond " (Essais, ii. 12), and the emblem he recommends a balance with the legend, " Que scay-je 1"might allowably be adduced as evidence of a more thoroughgoing Pyrrhonism. In his " tesmoynages de nostre imbecillite," he follows in the main the lines of the ancients, and he sums up with a lucid statement of the two great arguments in which the sceptical thought of every age resumes itselfthe impossibility of verifying our faculties, and the relativity of all impressions. The argument from the mutability of opinions and customs was probably the one which appealed most strongly to himself. In the concluding lines of this essay, Montaigne seems to turn to "nostre foy chrestienne " as man's only succour from his native state of helplessness and uncertainty. But undoubtedly his own habitual frame of mind is better represented in his celebrated saying'" How soft and healthful a pillow are ignorance and incuriousness .... for a well-ordered head." More inclined than Montaigne to give a religious turn to his reflexions was his friend Pierre Charron (1541-1603), who in his book De la Sagesse systematized in somewhat Scholastic fashion the train of thought which we find in the Essais. Francois Sanchez (1562-1632), professor of medicine and philo-sophy in Toulouse, combated the Aristotelianism of the schools with much bitterness, and was the author of a book with the title Quod nihil scitur. Of more or less isolated thinkers, somewhat later in point of time, who wrote in the same sceptical spirit, may be mentioned the names of Francois de la Mothe le Vayer (1588-1672), whose Cinq dialogues appeared after his death under the pseudonym of Orosius Tubero; Samuel Sorbiere (1615-1670), who trans-lated the Hypotyposes Pyrrhoneee of Sextus Empiricus; Simon Foucher (1644-1696), canon of Dijon, who wrote a History of the Academics, and combated Descartes and Malebranche from a sceptical standpoint. The work of Hieronymus Hirnhaim of Prague (1637-1679), De Typho Generis Humani sive Scientiarum Humanarum Inani ac Ventoso Tumore, was written in the interests of revelation. This is still more the case with the bitter polemic of Daniel Huet (1630-1721), Censura Philosophise Carte-sianx, and his later work, Traite Philosophique de la Faiblesse de I'Esprit Humain. The scepticism of Joseph Glanvill (1636-1680), in his two works The Vanity of Dogmatizing (1661) and Scepsis Scientifica (1665), has more interest for Englishmen. Glanvill was not a sceptic at all points, seeing that he was full of enthusiasm for the advance of physical science and for the newly-founded Royal Society. But he attacked unsparingly the Aristotel-ianism of the schools, which was still dominant at Oxford. Against this, and also against the materialistic dogmatism of Hobbes, he invoked the weapons of scepticism; and he was led by his own arguments to query " whether there be any science in the sense of the dogmatists." He based this conclusion partly upon the ground that our knowledge of causes, being derived simply from " concomitancy," is far from being "infallibly conclusive." "The causality itself," he says, anticipating Hume, " is insensible"; . accordingly, " the foundation of scientifical procedure is too wTeak for so magnificent a superstructure." More celebrated than any of the above was Pierre Bayle (1647-1706), whose scepticism lay more in his keen negative criticism of all systems and doctrines which came before him as literary historian than in any theoretic views of his own as to the possibility of knowledge. Bayle also paraded the opposition between reason and revelation ; but the argument in his hands is a double-edged weapon, and when he extols the merits of submissive faith his sincerity is at least questionable. Hume. Hume, the most illustrious and indeed the typical sceptic of modern times, is treated at length in a separate article. Here, therefore, it is only necessary to point out shortly in what his scepticism consists. It is sometimes placed, as we have seen it is by Kant, in his distrust of our ability and right to pass beyond the empirical sphere. But the mere denial of the possibility of " divinity or school meta-physics," as we find it in the Inquiry, combined with an apparent confidence in " experimental reasoning concern-ing matter of fact and existence," does not constitute scepticism, but rather what would now be called agnosticism or positivism. It is essential to the sceptical position that reason be dethroned within experience as well as beyond it, and this is undoubtedly the result at which Hume arrives in his larger and more thoroughgoing work. More generally, therefore, his scepticism may be considered to lie in his relation to preceding philosophy. The Treatise is a reductio ad absurdum of the principles of Lockianism, inasmuch as these principles, when consistently applied, leave the structure of experience entirely "loosened" (to use Hume's own expression), or cemented together only by the irrational force of custom. Hume's scepticism thus really arises from his thorough-going empiricism. Starting with " particular perceptions or isolated ideas let in by the senses, he never advances beyond these " distinct existences." Each of them exists on its own account; it is what it is, but it contains no reference to anything beyond itself. The very notion of objectivity and truth therefore disappears ; the Schein or appearance of the moment is the only reality. Hume's analysis of the conceptions of a permanent world and a permanent self reduces us to the sensationalistic relativism of Protagoras. He expressly puts this forward in various passages as the conclusion to which reason conducts us. The fact that the conclusion is in "direct and total opposition" to the apparent testimony of the senses is a fresh justification of philosophical scepticism. For, indeed, scepticism with regard to the senses is considered in the Inquiry to be sufficiently justified by the fact that they lead us to suppose "an external universe which depends not on our perception," whereas " this universal and primary opinion of all men is soon destroyed by the slightest philosophy." Scepticism with regard to reason, on the other hand, depends on an insight into the irrational character of the relation which we chiefly employ, viz., that of cause and effect. It is not a real relation in objects but rather a mental habit of belief engendered by frequent repetition or custom. This point of view is applied in the Treatise universally. All real connexion or relation, therefore, and with it all possibility of an objective system, disappears; it is, in fact, excluded by Hume a b initio, for " the mind never perceives any real connexion among distinct existences." Belief, however, just because it rests, as has been said, on custom and the influence of the imagination,1 survives such demonstrations. " Nature," as Hume delights to reiterate, " is always too strong for principle." " Nature, by an absolute and uncontrollable necessity, has determined us to judge as well as to breathe and feel." The true philosopher, therefore, is not the Pyrrhonist, trying to maintain an impossible equilibrium or suspense of judgment, but the Academic, yielding gracefully to the impressions or maxims which he finds, as matter of fact, to have most sway over himself. " I may' nay, I mustyield to the current of nature, in submitting to my senses and understanding; and in this blind submission I show most perfectly my sceptical principles," for, after all, " if we believe that fire warms or water refreshes, 'tis only because it costs us too much pains to think other-wise." 2
The system of Kant, or rather that part of his system Sceptical expounded in the Critique of Pure Season, though side of expressly distinguished by its author from scepticism, has Kantian, been included by many writers in their survey of sceptical theories. The difference between Kant, with his system of pure reason, and any of the thinkers we have passed in review is obvious; and his limitation of reason to the sphere of experience suggests in itself the title of agnostic or positivist rather than that of sceptic. Yet, if we go a little deeper, there is substantial justification for the view which treats agnosticism of the Kantian type as essentially sceptical in its foundations and in its results. For criticism not only limits our knowledge to a certain sphere, but denies that our knowledge within that sphere is real; we never know things as they actually are, but only as they appear to us. Our knowledge, in Kant's language, does not show us "the inward essence of the object in itself, but only the relation of the object to the subject." But this doctrine of relativity really involves a condemnation of our knowledge (and of all knowledge), because it fails to realize an impossible and self-contradictory ideal. The man who impeaches the knowing faculties because of the fact of relation which they involve is pursuing the phantom of an apprehension which, as Lotze expresses it, does not apprehend things, but is itself things; he is desiring not to know but to be the things themselves. If this dream or prejudice be exploded, then the scepticism originating in itand a large proportion of recent sceptical thought does so originate'loses its raison d'etre.3 The prejudice, however, which meets us in Kant is, in a some-what different form, the same prejudice which is found in Preju-the tropes of antiquitywhat Lotze calls " the inadmissible ^j^on relation of the world of ideas to a foreign world of objects." sceptj_
" It may he as well to add that the sceptical side of Kantianism is mainly confined to the Critique of Pure Reason, but this side of Kantian thought has been most widely influential. The remarks made above would not apply to the coherent system of idealism which may be evolved from Kant's writings and which many would consider alone to deserve the name of Kantianism or Criticism-
For, as he rightly points out, whether we suppose idealism or realism to be true, in neither case do the things them-selves pass into our knowledge. No standpoint is possible from which we could compare the world of knowledge with such an independent world of things, in order to judge of the conformity of the one to the other. But the abstract doubt " whether after all things may not be quite other in themselves than that which by the laws of our thought they necessarily appear" is a scepticism which, though admittedly irrefutable, is as certainly groundless. No arguments can be brought against it, simply because no arguments can be brought to support it; the scepticism rests on nothing more than the empty possibility of doubting. This holds true, even if we admit the " independent" existence of such a world of things. But the independence of things may with much greater reason be regarded as itself a fiction or prejudice. The real " objective" to which our thoughts must show con-formity is not a world of things in themselves, but the system of things as it exists for a perfect intelligence. Scepticism is deprived of its persistent argument if it is seen that, while our individual experiences are to be judged by their coherence with the context of experience in general, experience as a whole does not admit of being judged by reference to anything beyond itself.
To the attack upon the possibility of demonstration, inasmuch as every proof requires itself a fresh proof, it may quite fairly be retorted that the contradiction really lies in the demand for proof of the self-evident, on which all proof most ultimately depend. It is of course always possible that in any particular case we may be deceived ; we may be assuming as self-evidently true what is in reality not so. But such incidental lapses are found to correct themselves by the consequences in which they involve us, and they have no power to shake our trust in the general validity of reason. It may, however, be granted that the possibility of lapse throws us open to the objections, ingenuous or disingenuous, of the sceptic; and we must remain exposed to them so long as we deal with our first principles as so many isolated axioms or intui-tions. But the process of self-correction referred to points to another proofthe only ultimately satisfactory proof of which first principles admit. Their evidence lies in their mutual interdependence and in the coherence of the system which they jointly constitute.
Of a scepticism which professes to doubt the validity of every reasoning process and every operation of ail our faculties it is, of course, as impossible as it would be absurd to offer any refutation. Here, as Butler incisively put it, " we can go no further. For it is ridiculous to attempt to prove the truth of those very perceptions whose truth we can no otherwise prove than by other perceptions of exactly the same kind with them, and which there is just the same ground to suspect, or to attempt to prove the truth of our faculties, which can no otherwise be proved than by means of those very suspected faculties themselves." This absolute scepticism, indeed, can hardly be regarded as more than empty words; the position which they would indicate is not one which has ever existed. In any case, such scepticism is at all times sufficiently refuted by the imperishable and justifiable Function trust of reason in itself. The real function of scepticism of scepti- in the history of philosophy is relative to the dogmatism Clsm" which it criticizes. And, as a matter of fact, it has been seen that many so-called sceptics were rather critics of the effete systems which they found cumbering the ground than actual doubters of the possibility of knowledge in general. And even when a thinker puts forward his doubt as absolute it does not follow that his successors are bound to regard it in the same light. The progress of thought may show it to be, in truth, relative, as when the nerve of Hume's scepticism is shown to be his thoroughgoing empiricism, or when the scepticism of the Critique of Pure Reason is traced to the unwarrantable assumption of things-in-themselves. When the assump-tions on which it rests are proved to be baseless, the parti-cular scepticism is also overcome. In like manner, the apparent antinomies on which such a scepticism builds will be found to resolve themselves for a system based on a deeper insight into the nature of things. The serious thinker will always repeat the words of Kant that, in itself, scepticism is " not a permanent resting-place for human reason." Its justification is relative and its func-tion transitional.
Authorities.Ancient scepticism is fully treated in the relative parts of Zeller's Philosophie der Griechen, with which may be compared Zimmermannes Darstellung d. Pyrrhonischen Philosophie (1841), and JJeber Ursprung u. Bedeutung d. Pyrrh. Phil. (1843); Wachsmuth, De Timone Phliasio (1859); Geffeis, De Arcesila (1849); Norman MacColl, Greek Sceptics from Pyrrho to Sextus (1869); Haas, De Philosophorum Scepticorum Successionibus (1875).
Among other works may be mentioned Stäudlin, Geschichte und Geist d. Scepticismus, vorzüglich in Rücksicht auf Moral u. Religion (1794) ; Tafel, Geschichte d. Scepticismus (1834) ; E. Saisset, Le Scepticisme: JEnCsideme, Pascal, Kant (1875). (A. SE.)
"Pour juger des apparences que nous recevons des subjects, il nous fauldra un instrument judicatoire j pour verifier cet instrument, il nous y fault de la demonstration ; pour verifier la demonstration, un instrument; nous voyla au rouet. . . Finalement il n'y a aulcune constante existence, ny de nostre estre ny de celuy des objects ; et nous, et nostre jugement, et toutes choses mortelles, vont coulant et roulant sans cesse ; ainsin, il ne se peult establir rien de certain de l'un a l'aultre, et le jugeant et le juge estants en continuelle mutation et bransle "
1 This turn of thought is not confined, however, to Christian thinkers; it appears also in the Arabian philosophy of the East. Al- C4hazzali (Algazel) (1059-1111) in his Tahdfot al-Fildsifa ("The Collapse of the Philosophers") is the advocate of complete philo-sophical scepticism in the interests of orthodox Mohammedanisman orthodoxy which passed, however, in his own case into a species of mysticism. He did his work of destruction so thoroughly that Arabian philosophy died ou* after his time in the land of its birth.
1 " Belief is more properly an act of the sensitive than of the cogitative part of our nature." rests.
2 Much the same conclusion is reached in what is perhaps the ablest English exposition of pure philosophic scepticism since Hume Mr Arthur Balfour's Defence of Philosophic Doubt (1879). " The reader may wish to know," says Mr Balfour, "what constitute the ' claims on our belief' which I assert to he possessed alike by science and theology, and which I put forward as the sole practical founda-tion on which our convictions ultimately rest. . . . Whatever they may be, they are not rational grounds of conviction. . . It would be more proper to describe them as a kind of inward inclination or impulse" (pp. 316-7).