THREE:With the introduction of practical questions, we pass to the great positive achievement of Carneades, his theory of probable evidence. Intended as an account of the process by which belief is adjusted to safe action rather than of the process by which it is brought into agreement with reality, his logic is a systematisation of the principles by which prudent men are unconsciously guided in common life. Carneades distinguishes three degrees of probability. The lowest is attached to simple perception. This arises when we receive the impression of an object without taking the attendant circumstances into account. The next step is reached when our first impression is confirmed by the similar impressions received from its attendant circumstances; and when each of these, again, bears the test of a similar examination our assurance is complete. The first belief is simply probable; the second is probable and uncontradicted; the third probable, uncontradicted, and methodically established. The example given by Sextus is that of a person who on seeing a coil of rope in a dark passage thinks that it may be a snake, and jumps over it, but on turning round and observing that it remains motionless feels inclined to form a different opinion. Remembering, however, that snakes are sometimes congealed by cold in winter, he touches the coil with his stick, and finally satisfies himself by means of this test that the image present to his mind does not really represent a snake. The circumstances to be examined before arriving at a definite judgment include such considerations as whether our senses are in a healthy condition, whether we are wide awake, whether the air is clear, whether the object is steady, and whether we have taken time enough to be sure that the conditions here specified are fulfilled. Each degree of probability is, again, divisible into several gradations according to the strength of the155 impressions received and the greater or less consilience of all the circumstances involved.252The most important result of the old Pythagorean teaching was, that it contributed a large elementsomewhat too large, indeed,to Platos philosophy. Neo-Pythagoreanism bears precisely the same relation to that revived Platonism which was the last outcome of ancient thought. It will be remembered that the great controversy between Stoicism and Scepticism, which for centuries divided the schools of Athens, and was passed on by them to Cicero and his contemporaries, seemed tending towards a reconciliation based on a return to the founder of the Academy, when, from whatever cause, Greek speculation came to a halt, which continued until the last third of the first century after Christ. At that epoch, we find a great revival of philosophical interest, and this revival seems to have been maintained for at least a hundred years, that is to say, through the whole of what is called the age of the Antonines. In the struggle for existence among the rival sects which ensued, Platonism started with all the advantages that a great inheritance and a great name could bestow. At the commencement of this period, we find the Academy once more professing to hold the doctrines of its founder in their original purity and completeness. Evidently the sober common-sense view of Antiochus had been discarded, and Platos own writings were taken as an authoritative standard of truth. A series of industrious commentators undertook the task of elucidating their contents. Nor was it only in the schools that their influence was felt. The beauty of their style must have strongly recommended the Dialogues to the attention of literary men. Plutarch, the most considerable Greek writer of his time, was a declared Platonist. So251 also was the brilliant African novelist, Apuleius, who flourished under Marcus Aurelius. Celsus, the celebrated anti-Christian controversialist, and Maximus, the Tyrian rhetorician, professed the same allegiance; and the illustrious physiologist Galen shows traces of Platonic influence. Platonism, as first constituted, had been an eminently religious philosophy, and its natural tendencies were still further strengthened at the period of its revival by the great religious reaction which we have been studying in the present chapter; while, conversely, in the struggle for supremacy among rival systems, its affinities with the spirit of the age gave it an immense advantage over the sceptical and materialistic philosophies, which brought it into still closer sympathy with the currents of popular opinion. And its partisans were drawn even further in the same direction by the influence of Neo-Pythagoreanism, representing, as this did, one among the three or four leading principles which Plato had attempted to combine.
One morning, when Gregor Samsa woke from troubled dreams
