History of Western Philosophy - Bertrand Russell [138]
It should be observed that Scepticism as a philosophy is not merely doubt, but what may be called dogmatic doubt. The man of science says 'l think it is so-and-so, but I am not sure.' The man of intellectual curiosity says 'I don't know how it is, but I hope to find out.' The philosophical Sceptic says 'nobody knows, and nobody ever can know.' It is this element of dogmatism that makes the system vulnerable. Sceptics, of course, deny that they assert the impossibility of knowledge dogmatically, but their denials are not very convincing.
Pyrrho's disciple Timon, however, advanced some intellectual arguments which, from the standpoint of Greek logic, were very hard to answer. The only logic admitted by the Greeks was deductive, and all deduction had to start, like Euclid, from general principles regarded as self-evident. Timon denied the possibility of finding such principles. Everything, therefore, will have to be proved by means of something else, and all argument will be either circular or an endless chain hanging from nothing. In either case nothing can be proved. This argument, as we can see, cut at the root of the Aristotelian philosophy which dominated the Middle Ages.
Some forms of Scepticism which, in our own day, are advocated by men who are by no means wholly sceptical, had not occurred to the Sceptics of antiquity. They did not doubt phenomena, or question propositions which, in their opinion, only expressed what we know directly concerning phenomena. Most of Timon's work is lost, but two surviving fragments will illustrate this point. One says 'The phenomenon is always valid.' The other says: 'That honey is sweet 1 refuse to assert; that it appears sweet, I fully grant.'6 A modern Sceptic would point out that the phenomenon merely occurs, and is not either valid or invalid; what is valid or invalid must be a statement, and no statement can be so closely linked to the phenomenon as to be incapable of falsehood. For the same reason, he would say that the statement 'honey appears sweet' is only highly probable, not absolutely certain.
In some respects, the doctrine of Timon was very similar to that of Hume. He maintained that something which had never been observed—atoms, for instance—could not be validly inferred; but when two phenomena had been frequently observed together, one could be inferred from the other.
Timon lived at Athens throughout the later years of his long life, and died there in 235 B.C. With his death, the school of Pyrrho, as a school, came to an end but his doctrines, somewhat modified, were taken up, strange as it may seem, by the Academy, which represented the Platonic tradition.
The man who effected this surprising philosophic revolution was Arcesilaus, a contemporary of Timon, who died as an old man about 240 B.C. What most men have taken from Plato is belief in a supersensible intellectual world and in the superiority of the immortal soul to the mortal body. But Plato was many-sided, and in some respects could be regarded as teaching scepticism. The Platonic Socrates professes to know nothing; we naturally treat this as irony, but it could be taken seriously. Many of the dialogues reach no positive conclusion, and aim at leaving the reader in a state of doubt. Some—the latter half of the Parmenides, for instance—might seem to have no purpose except to show that either side of any question can be maintained with equal plausibility. The Platonic dialectic could be treated as an end, rather than a means, and if so treated it lent itself admirably to the advocacy of Scepticism. This seems to have been the way in which Arcesilaus interpreted the man whom he still professed to follow. He had decapitated