Thus we find Pyrrho competing with the dogmatists as a practical moralist, and offering to secure the inward tranquillity at which they too aimed by an easier method than theirs. The last eminent representative of the sceptical school, Sextus Empiricus, illustrates its pretensions in this respect by the well-known story of Apelles, who, after vainly endeavouring to paint the foam on a horse’s mouth, took the sponge which he used to wipe his easel, and threw it at the picture in vexation. The mixture of colours thus accidentally applied produced the exact effect which he desired, but at which no calculation could arrive. In like manner, says Sextus, the confusion of universal doubt accidentally resulted in the imperturbability which accompanies suspense of judgment as surely as a body is followed by its shadow.[229] There was, however, no accident about the matter at all. The abandonment of those studies which related to the external world was a consequence of the ever-increasing attention paid to human interests, and that these could be best consulted by complete detachment from outward circumstances, was a conclusion inevitably suggested by the negative or antithetical moment of Greek thought. Hence, while the individualistic and apathetic tendencies of the age were shared by every philosophical school, they had a closer logical connexion with the idealistic than with the naturalistic method; and so it is among the successors of Protagoras that we find them developed with the greatest distinctness; while their incorporation with Stoicism imposed a self-contradictory strain on that system which it never succeeded in shaking off. Epicureanism occupied a position midway between the two extremes; and from this point of view, we shall be better able to understand both its inherent weakness as compared with the other ancient philosophies, and the admiration which it has attracted from opposite quarters in recent years. To some it is most interesting as a revelation of law in Nature, to others as a message of deliverance to man—not merely a deliverance from ignorance and passion, such as its rivals had promised, but from all established systems, whether religious, political, or scientific. And unquestionably Epicurus did endeavour to combine both points of view in his theory of life. In seeking to base morality on a knowledge of natural law he resembles the Stoics. In his attacks on fatalism, in his refusal to be bound down by a rigorously scientific explanation of phenomena, in his failure to recognise the unity and power of Nature, and in his preference of sense to reason, he partially reproduces the negative side of Scepticism; in his identification of happiness with the tranquil and imperturbable self-possession of mind, in his mild humanism, and in his compliance with the established religion of the land, he entirely reproduces its positive ethical teaching. On the other hand, the two sides of his philosophy, so far from completing, interfere with and mar one another. Emancipation from the outward world would have been far more effectually obtained by a total rejection of physical science than by the construction of a theory whose details were, on any scientific principles, demonstrably untrue. The appeal to natural instinct as an argument for hedonism would, consistently followed out, have led to one of two conclusions, either of which is incompatible with the principle that imperturbability is the highest good. If natural instinct, as manifested by brutes, by children, and by savages, be the one sure guide of action, then Callicles was right, and the habitual indulgence of passion is wiser than its systematic restraint. But if Nature is to be studied on a more specific and discriminating plan, if there are human as distinguished from merely animal impulses, and if the higher development of these should be our rule of life, then Plato and Aristotle and the Stoics were right, and the rational faculties should be cultivated for their own sake, not because of the immunity from superstitious terrors which they secure. And we may add that the attendance on public worship practised by Epicurus agreed much better with the sceptical suspense of judgment touching divine providence than with its absolute negation, whether accompanied or not by a belief in gods who are indifferent to sacrifice and prayer.
It was, no doubt, for these and similar reasons that all the most vigorous intellects of Hellas ranged themselves either on the Stoic or on the Sceptic side, leaving the halfhearted compromise of Epicurus to those who could not think out any one theory consistently, or who, like the Romans at first, were not acquainted with any system but his. Henceforth, during a period of some centuries, the whole philosophic movement is determined by the interaction of these two fundamental forces. The first effect of their conflict was to impose on Scepticism an important modification, illustrating its essentially parasitic character. We have seen it, as a general tendency of the Greek mind, clinging to the very texture of mythology, accompanying the earliest systematic compilation of facts, aiding the humanistic attacks on physical science, associated with the first great religious reaction, operating as the dialectic of dialectic itself, and finally assuming the form of a shadowy morality, in rivalry with and imitation of ethical systems based on a positive and substantial doctrine. We have now to trace its metamorphosis into a critical system extending its ramifications in parallelism with the immense dogmatic structure of Stoicism, and simultaneously endeavouring to reach the same practical results by a more elastic adaptation to the infirmities of human reason and the uncertainties of sensible experience. As such, we shall also have to study its influence over the most plastic of Roman intellects, the great orator in whose writings Greek philosophy was reclothed with something of its ancient charm, so that many who were debarred from admission to the groves and porticoes of Athens have caught an echo of the high debates which once stirred their recesses, as they trod the shady slopes of Tusculum under his visionary guidance, or followed his searching eyes over the blue waters to Pompeii, while he reasoned on mind and its object, on sense and knowledge, on doubt and certainty, with Lucullus and Hortensius, on the sunlight Baian shore. It is the history of the New Academy that we shall now proceed to trace.
V.
When we last had occasion to speak of the Platonic school, it was represented by Polemo, one of the teachers from whose lessons Zeno the Stoic seems to have compiled his system. Under his superintendence, Platonism had completely abandoned the metaphysical traditions of its founder. Physics and dialectics had already been absorbed by Aristotelianism. Mathematics had passed into the hands of experts. Nothing remained but the theory of ethics; and, as an ethical teacher, Polemo was only distinguished from the Cynics by the elegance and moderation of his tone. Even this narrow standing-ground became untenable when exposed to the formidable competition of Stoicism. The precept, Follow Nature, borrowed by the new philosophy from Polemo, acquired a far deeper significance than he could give it, when viewed in the light of an elaborate physical system showing what Nature was, and whither her guidance led. But stone after stone had been removed from the Platonic superstructure and built into the walls of other edifices, only to bring its original foundation the more prominently into sight. This was the initial doubt of Socrates, widened into the confession of universal ignorance attributed to him by Plato in the Apologia. Only by returning to the exclusively critical attitude with which its founder had begun could the Academy hope to exercise any influence on the subsequent course of Greek speculation. And it was also necessary that the agnostic standpoint should be taken much more in earnest by its new representatives than by Socrates or Plato. With them it had been merely the preparation for a dogmatism even more self-confident than that of the masters against whom they fought; but if in their time such a change of front might seem compatible with the retention of their old strongholds, matters now stood on a widely different footing. Experience had shown that the purely critical position could not be abandoned without falling back on some one or other of the old philosophies, or advancing pretensions inconsistent with the dialectic which had been illustrated by their overthrow. The course marked out for Plato’s successors by the necessities of thought might have been less evident had not Pyrrhonism suddenly revealed to them where their opportunities lay, and at the same time, by its extinction as an independent school, allowed them to step into the vacant place.
It was at this juncture that the voluntary withdrawal of an older fellow-pupil placed Arcesilaus at the head of the Academy. The date of his accession is not given, but we are told that he died 241 or 240 B.C. in the seventy-fifth year of his age. He must, therefore, have flourished a generation later than Zeno and Epicurus. Accomplished, witty, and generous, his life is described by some as considerably less austere than that of the excellent nonentities whom he succeeded. Yet its general goodness was testified to by no less an authority than his contemporary, the noble Stoic, Cleanthes. ‘Do not blame Arcesilaus,’ exclaimed the latter to an unfriendly critic; ‘if he denies duty in his words, he affirms it in his deeds.’ ‘You don’t flatter me,‘ observed Arcesilaus. ‘It is flattering you,’ rejoined Cleanthes, ‘to say that your actions belie your words.’[230] It might be inferred from this anecdote that the scepticism of the new teacher, like that of Carneades after him, was occasionally exercised on moral distinctions, which, as then defined and deduced, were assuredly open to very serious criticism. Even so, in following the conventional standard of the age, he would have been acting in perfect consistency with the principles of his school. But, as a matter of fact, his attacks seem to have been exclusively aimed at the Stoic criterion of certainty. We have touched on this difficult subject in a former chapter, but the present seems a more favourable opportunity for setting it forth in proper detail.
The Stoics held, as Mr. Herbert Spencer, who resembles them in so many respects, now holds, that all knowledge is ultimately produced by the action of the object on the subject. Being convinced, however, that each single perception, as such, is fallible, they sought for the criterion of certainty in the repetition and combination of individual impressions; and, again like Mr. Spencer, but also in complete accordance with their dynamic theory of Nature, they estimated the validity of a belief by the degree of tenacity with which it is held. The various stages of assurance were carefully distinguished and arranged in an ascending series. First came simple perception, then simple assent, thirdly, comprehension, and finally demonstrative science. These mental acts were respectively typified by extending the forefinger, by bending it as in the gesture of beckoning, by clenching the fist, and by placing it, thus clenched, in the grasp of the other hand. From another point of view, they defined a true conviction as that which can only be produced by the action of a corresponding real object on the mind. This theory was complicated still further by the Stoic interpretation of judgment as a voluntary act; by the ethical significance which it consequently received; and by the concentration of all wisdom in the person of an ideal sage. The unreserved bestowal of belief is a practical postulate dictated by the necessities of life; but only he who knows what those necessities are, in other words only the wise man, knows when the postulate is to be enforced. In short, the criterion of your being right is your conviction that you are right, and this conviction, if you really possess it, is a sufficient witness to its own veracity. Or again, it is the nature of man to act rightly, and he cannot do so unless he has right beliefs, confirmed and clinched by the consciousness that they are right.
Arcesilaus left no writings, and his criticisms on the Stoic theory, as reported by Cicero and Sextus Empiricus, have a somewhat unsatisfactory appearance. By what we can make out, he seems to have insisted on the infallibility of the wise man to a much greater extent than the Stoics themselves, not allowing that there was any class of judgments in which he was liable to be mistaken. But just as the Stoics were obliged to accept suicide as an indispensable safeguard for the inviolability of their personal dignity and happiness, so also Arcesilaus had recourse to a kind of intellectual suicide for the purpose of securing immunity from error. The only way, according to him, in which the sage can make sure of never being mistaken is never to be certain about anything. For, granting that every mental representation is produced by a corresponding object in the external world, still different objects are connected by such a number of insensible gradations that the impressions produced by them are virtually indistinguishable from one another; while a fertile source of illusions also exists in the diversity of impressions produced by the same object acting on different senses and at different times. Moreover, the Stoics themselves admitted that the sage might form a mistaken opinion; it was only for his convictions that they claimed unerring accuracy, each of the two—opinion and conviction—being the product of a distinct intellectual energy. Here again, Arcesilaus employed his method of infinitesimal transitions, refusing to admit that the various cognitive faculties could be separated by any hard and fast line; especially as, according to the theory then held by all parties, and by none more strongly than the Stoics, intellectual conceptions are derived exclusively from the data of sense and imagination. We can see that the logic of Scepticism is, equally with that of the other Greek systems, determined by the three fundamental moments of Greek thought. There is first the careful circumscription of certainty; then there is the mediating process by which it is insensibly connected with error; and, lastly, as a result of this process, there is the antithetical opposition of a negative to an affirmative proposition on every possible subject of mental representation.[231]
To the objection that his suspensive attitude would render action impossible, Arcesilaus replied that any mental representation was sufficient to set the will in motion; and that, in choosing between different courses, probability was the most rational means of determination. But the task of reducing probable evidence to a system was reserved for a still abler dialectician, who did not appear on the scene until a century after his time. Arcesilaus is commonly called the founder of the Middle, Carneades the founder of the New Academy. The distinction is, however, purely nominal. Carneades founded nothing. His principles were identical with those of his predecessor; and his claim to be considered the greatest of the Greek sceptics is due to his having given those principles a wider application and a more systematic development. The Stoics regarded it as a special dispensation of providence that Chrysippus, the organising genius of their school, should have come between its two most formidable opponents, being thus placed in a position to answer the objections of the one and to refute by anticipation those of the other.[232] It might seem to less prejudiced observers that the thinker whose cause benefited most by this arrangement was Carneades. Parodying a well-known iambic, he used to say:
‘Without Chrysippus I should not have been.’[233]
And, in fact, it was by a close study of that writer’s voluminous treatises that he was able to cover the immense extent of ground which Scepticism thenceforward disputed with the dogmatic schools. Nor were his attacks directed against Stoicism only, but against all other positive systems past and present as well. What he says about the supposed foundation of knowledge is even now an unanswerable objection to the transcendental realism of Mr Herbert Spencer. States of consciousness speak for themselves alone, they do not include the consciousness of an external cause.[234] But the grounds on which he rests his negation of all certainty are still superficial enough, being merely those sensible illusions which the modern science of observation has been able either to eliminate altogether or to restrict within narrow and definable limits. That phenomena, so far from being necessarily referred to a cause which is not phenomenal, cannot be thought of at all except in relation to one another, and that knowledge means nothing more than a consciousness of this relation, was hardly perceived before the time of Hume.