The method by which Plato eventually found his way out of the sceptical difficulty, was to transform it from a subjective law of thought into an objective law of things. Adopting the Heracleitean physics as a sufficient explanation of the material world, he conceived, at a comparatively early period of his mental evolution, that the fallaciousness of sense-impressions is due, not to the senses themselves, but to the instability of the phenomena with which they deal; and afterwards, on discovering that the interpretation of ideal relations was subject to similar perplexities, he assumed that, in their case also, the contradiction arises from a combination of Being with not-Being determining whatever differences prevail among the ultimate elements of things. And, finally, like Empedocles, he solved the problem of cognition by establishing a parallel between the human soul and the universe as a whole; the circles of the Same and the Other being united in the celestial orbits and also in the mechanism of the brain.[223]
It was by an analogous, though, of course, far more complicated and ingenious adjustment, that Hegel sought to overcome the agnosticism which Kant professed to have founded on a basis of irrefragable proof. With both philosophers, however, the sceptical principle was celebrating its supreme triumph at the moment of its fancied overthrow. The dogmatism of doubt could go no further than to resolve the whole chain of existence into a succession of mutually contradictory ideas.
If the synthesis of affirmation and negation cannot profitably be used to explain the origin of things in themselves, it has a real and very important function when limited to the subjective sphere, to the philosophy of practice and of belief. It was so employed by Socrates, and, on a much greater scale, by Plato himself. To consider every proposition from opposite points of view, and to challenge the claim of every existing custom on our respect, was a proceeding first instituted by the master, and carried out by the disciple in a manner which has made his investigations a model for every future enquirer. Something of their spirit was inherited by Aristotle; but, except in his logical treatises, it was overborne by the demands of a pre-eminently dogmatic and systematising genius. In criticising the theories of his predecessors, he has abundantly illustrated the power of dialectic, and he has enumerated its resources with conscientious completeness; but he has not verified his own conclusions by subjecting them to this formidable testing apparatus.
Meanwhile the scepticism of Protagoras had not been entirely absorbed into the systems of his rivals, but continued to exist as an independent tradition, or in association with a simpler philosophy. The famous school of Megara, about which, unfortunately, we have received very little direct information, was nominally a development of the Socratic teaching on its logical side, as the Cynic and Cyrenaic schools were on its ethical side, but like them also, it seems to have a more real connexion with the great impulse previously given to speculation by the Sophists. At any rate, we chiefly hear of the Megarians as having denied the possibility of definition, to which Socrates attached so much importance, and as framing questions not susceptible of a categorical answer,—an evident satire on the Socratic method of eliciting the truth by cross-examination.[224] What they really derived from Socrates seems to have been his mental concentration and independence of external circumstances. Here they closely resembled the Cynics, as also in their contempt for formal logic; but while Antisthenes found a sanction for his indifference and impassivity in the order of nature, their chief representative, Stilpo, achieved the same result by pushing the sceptical principle to consequences from which even the Cyrenaics would have shrunk. Denying the possibility of attaching a predicate to a subject, he seems, in like manner, to have isolated the mind from what are called its affections, or, at least, to have made this isolation his ideal of the good. Even the Stoics did not go to such a length; and Seneca distinguishes himself from the followers of Stilpo by saying, ‘Our sage feels trouble while he overcomes it, whereas theirs does not feel it at all.’[225]
IV.
So far, the sceptical theory had been put forward after a somewhat fragmentary fashion, and in strict dependence on the previous development of dogmatic philosophy. With the Humanists it had taken the form of an attack on physical science; with the Megarians, of a criticism on the Socratic dialectic; with both, it had been pushed to the length of an absolute negation, logically not more defensible than the affirmations to which it was opposed. What remained was that, after being consistently formulated, its results should be exhibited in their systematic bearing on the practical interests of mankind. The twofold task was accomplished by Pyrrho, whose name has accordingly continued to be associated, even in modern times, with the profession of universal doubt. This remarkable man was a native of Elis, where a branch of the Megarian school had at one time established itself; and it seems likely that the determining impulse of his life was, directly or indirectly, derived from Stilpo’s teaching. A contemporary of Alexander the Great, he accompanied the Macedonian army on its march to India, subsequently returning to his native city, where he died at an advanced age, about 275 B.C. The absurd stories about his indifference to material obstacles when out walking have been already mentioned in a former chapter, and are sufficiently refuted by the circumstances just related. The citizens of Elis are said to have shown their respect for the philosopher by exempting him from taxation, appointing him their chief priest—no inappropriate office for a sceptic of the true type—and honouring his memory with a statue, which was still pointed out to sightseers in the time of Pausanias.[226]
Pyrrho, who probably no more believed in books than in anything else, never committed his opinions to writing; and what we know of them is derived from the reports of his disciples, which, again, are only preserved in a very incomplete form by the compilers of the empire. According to these, Pyrrho began by declaring that the philosophic problem might be summed up in the three following questions: ‘What is the nature of things? What should be our relation to them? What is the practical consequence of this determination?’ Of its kind, this statement is probably the best ever framed, and might be accepted with equal readiness by every school of thought. But the scepticism of Pyrrho at once reveals itself in his answer to the first question. We know nothing about things in themselves. Every assertion made respecting them is liable to be contradicted, and neither of the two opposing propositions deserves more credence than the other. The considerations by which Pyrrho attempts to establish this proposition were probably suggested by the systems of Plato and Aristotle. The only possible avenues of communication with the external world are, he tells us, sense and reason. Of these the former was so universally discredited that he seems to have regarded any elaborate refutation of its claims as superfluous. What we perceive by our senses is the appearance, not the reality of things. This is exactly what the Cyrenaics had already maintained. The inadequacy of reason is proved by a more original method. Had men any settled principles of judgment, they would agree on questions of conduct, for it is with regard to these that they are best informed, whereas the great variety of laws and customs shows that the exact opposite is true. They are more hopelessly divided on points of morality than on any other.[227] It will be remembered that Pyrrho’s fellow-townsman, Hippias, had, about a hundred years earlier, founded his theory of Natural Law on the arbitrary and variable character of custom. The result of combining his principles with those professed by Protagoras and Gorgias was to establish complete moral scepticism; but it would be a mistake to suppose that moral distinctions had no value for him personally, or that they were neglected in his public teaching.
Timon, a celebrated disciple of Pyrrho, added another and, from the speculative point of view, a much more powerful argument, which, however, may equally have been borrowed from the master’s lectures. Readers of the Posterior Analytics will remember how strongly Aristotle dwells on the necessity of starting with first principles which are self-evidently true. The chain of demonstration must have something to hang on, it cannot be carried back ad infinitum. Now, Timon would not admit of such a thing as first principles. Every assumption, he says, must rest on some previous assumption, and as this process cannot be continued for ever, there can be no demonstration at all. This became a very favourite weapon with the later Sceptics, and, still at the suggestion of Aristotle, they added the further ‘trope’ of compelling their adversaries to choose between going back ad infinitum and reasoning in a circle—in other words, proving the premises by means of the conclusion. Modern science would not feel much appalled by the sceptical dilemma. Its actual first principles are only provisionally assumed as ultimate, and it is impossible for us to tell how much farther their analysis may be pursued; while, again, their validity is guaranteed by the circular process of showing that the consequences deduced from them agree with the facts of experience. But as against those modern philosophers who, in adherence to the Aristotelian tradition, still seek to base their systems on first principles independent of any individual experience, the sceptical argument is unanswerable, and has even been strengthened by the progress of knowledge. To this day, thinkers of different schools cannot agree about the foundations of belief, and what to one seems self-evidently true, is to another either conceivably or actually false. To Mr. Herbert Spencer the persistence of force is a necessary truth; to Prof. Stanley Jevons its creation is a perfectly possible contingency; while to others, again, the whole conception of force, as understood by Mr. Spencer, is so absolutely unmeaning that they would decline to entertain any proposition about the invariability of the objective reality which it is supposed to represent. And when the à priori dogmatist affects to treat the negations of his opponents as something that they do not think, but only think they think, they may, with perfect fairness, attribute his rejection of their beliefs—as, for example, free-will—to a similar subjective illusion. Moreover, the pure experimentalists can point to a circumstance not foreseen by the ancient sceptics, which is that propositions once generally regarded as incontrovertible by thinking men, are now as generally abandoned by them.
Having proved, to his satisfaction, that the nature of things is unknowable, Pyrrho proceeds to deal with the two remaining heads of the philosophic problem. To the question what should be our relation to a universe which we cannot reach, the answer is, naturally, one of total indifference. And the advantage to be derived from this attitude is, he tells us, that we shall secure the complete imperturbability wherein true happiness consists. The sceptical philosophy does not agree with Stilpo in denying the reality of actual and immediate annoyances, for it denies nothing; but it professes to dispel that very large amount of unhappiness which arises from the pursuit of fancied goods and the expectation of future calamities. In respect to the latter, what Pyrrho sought was to arrive by the exercise of reasoning at the tranquillity which unreasoning animals naturally enjoy. Thus, we are told that, when out at sea in a storm, he called the attention of the terrified passengers to a little pig which was quietly feeding in spite of the danger, and taught them that the wise man should attain to a similar kind of composure.
Various other anecdotes of more or less doubtful authenticity are related, showing that the philosopher could generally, though not always, act up to his own ideal of indifference. He lived with his sister, who was a midwife by profession, and patiently submitted to the household drudgery which she unsparingly imposed on him. Once, however, she succeeded in goading him into a passion; and on being rather inopportunely reminded of his professed principles by a bystander, the sceptic tartly replied that a wretched woman like that was no fit subject for a display of philosophical indifference. On another occasion, when taunted for losing his self-possession at the attack of a furious dog, he observed, with truth, that, after all, philosophers are human beings.[228]