Plato’s realism.
62. A striking feature of the Platonic dialogues is that their results are usually negative. First the opinions of the crowd, then those of Socrates’ contemporaries the ‘sophists’ and of the other Socratic schools are subjected to a cross-examination, under which they are one and all shewn to be unreasonable. This cross-examination is quite in the Socratic spirit, and is before all things a mental gymnastic, training the dialectician to observe with keener eye and to discuss with apter tongue than his fellows. Gradually there emerges from a mass of doubts something like a positive theory that Plato is prepared to adopt. The true reasoning is that of induction from the particular to the general, from the individual to the class. In the class name we come upon the true being of the individual, and by a right definition of it we discern what each thing really is. The ‘idea,’ which corresponds to the class name, is alone really existent; the individual is a more or less imperfect imitation of it (μίμησις). In this way Plato found what seemed to him a solution of a difficulty which Socrates hardly felt, that of explaining the participation (μέθεξις) of the particular in the general (ὑπόθεσις or ἰδέα). Thus where ordinary men see ‘horses,’ and Antisthenes holds that they are right, Plato sees ‘horsiness,’ or the idea of ‘horse.’ In the language of medieval philosophy Plato is a realist, that is, one who holds that our Ideas are more than what men mean when they say ‘mere ideas’; that they are Realities, and have their being in a truly existing world; and that in knowing them we know what is. But just as Plato holds that general conceptions are alone true and real, so he necessarily maintains that objects perceivable by the senses are only half-real, and that the ordinary man lives in a world of illusions. Thus the thoughts of the philosopher are separated by an abyss from the world in which men live and die.
God and the soul.
63. Upon the basis of the individual ‘ideas’ Plato builds up by a process of classification and induction higher and smaller classes of ideas, until we begin to see the vision of a single idea, a class which includes all classes, a supreme ‘being’ from which all being is derived. This highest idea is variously suggested by the names ‘the Good,’ ‘the Beautiful,’ ‘the One.’ By a sudden transformation it becomes the Creator (δημιουργός) of the universe. Containing in itself all being, it needs for its operation some kind of formless and inert matter; for this the name ἄπειρον, ‘the unlimited,’ is taken from Anaximander. The whole created universe may be considered as the joint production of the ‘idea’ and the ‘unlimited’; and the cosmology of Anaxagoras, ‘all things were together, and mind came and ordered them,’ is substantially justified. The world thus created is both good and beautiful, for it is made by a good Creator on the best of patterns.
The human soul is of triple nature. The highest part, the rational soul (τὸ λογιστικόν), is seated in the head; the emotional soul (τὸ θυμοειδές) in the heart; the appetitive soul (τὸ ἐπιθυμητικόν) in the belly. Over these two lower souls the reasoning part should hold control, as a driver over two unruly steeds[6]. The rational soul has existed before birth, and may hope for immortality, for it is knit up with the idea of ‘being.’ Ultimately it may even attain to perfection, if it is purified as by fire from baser elements that have attached themselves to it.
Ethics and Politics.
64. Plato himself does not formulate an ethical ideal of the same precision that his successors used, but we infer from his works a goal towards which he points. Thus the ethical end for each man is the greatest possible participation in the idea of the good, the closest attainable imitation of the deity. The virtue of each part of the human soul lies in the fit performance of its proper work; that of the reasoning soul is Wisdom (σοφία); of the emotional soul Courage (ἀνδρεία); of the appetitive soul Soberness (σοφροσύνη). Over all (it is hinted rather than stated) rules the supreme virtue of Justice (δικαιοσύνη), assigning to each part its proper function. Thus the four cardinal virtues are deduced as a practical application from the Platonic psychology. The high position assigned to Justice leads up to the practical doctrine of Moderation (μετριότης); even the virtues are restricted both in their intensity and in their spheres of work, and if any virtue passes its proper limit it becomes changed into the vice that borders on it. Thus the ideal of practical life is the ‘moderate man,’ calm, considerate, and self-respecting, touched with a warm flow of feeling, but never carried away into excitement; and even this ideal is strictly subordinate to that of the life of philosophic contemplation.
The ideal State is modelled on the individual man. To the three parts of the soul correspond three classes of citizens; the rulers, whose virtue is Wisdom; the guardians, on whom Courage is incumbent; the labourers and tradesmen, who owe the State Soberness and obedience. Thus the political system to which Plato leans is that of an Aristocracy; for the middle class in his state has only an executive part in the government, and the lower orders are entirely excluded from it.
Aristotle.
65. By far the greatest of Plato’s pupils was Aristotle of Stagira (384-322 B.C.), who introduced into philosophy, now convulsed by the disputes of the disciples of Socrates, a spirit of reconciliation. From his point of view the various contentions are not so much erroneous as defective. To attain the truth we need first to collect the various opinions that are commonly held, and then to seek the reconciling formula of which each one is a partial statement.