deepest feeling always gravitated toward morality. Was it possible for them to form a conception of the universal principle such as we can form? They had not the wealth of discovered facts which science has bequeathed to our age. Could they reason that light and radiant heat are different aspects of one kind of energy; that the ray of light reaching us from the farthest star is not a fluid passing from space to space, but a definite agitation of an interstellar medium of infinite extension, and that therefore there can be no break in it, no absolute vacuum; that the universe is a plenum; that all differences between resistance and non-resistance, between matter and space, are relative, not absolute? Could they have ascertained the fact that all words meaning unconditioned, such as absolute, abstract sequence, or force considered apart from matter, were simply outgrowths of the conception of Time, that they can mean nothing more than is given in this subjective aspect of Motion? Or could they have known that all words signifying unlimited, such as infinite, abstract co-existence, extension, or matter considered apart from force, were simply outgrowths of the conception of Space, that they can mean nothing more than is given in this objective aspect of Motion? This deepest of all truths, the idea of one in three and three in one, has been dimly reflected in the minds of the oldest thinkers which even tradition tells of; it has found its way into religions and taken upon itself interpretations which almost forbid its recognition; but it is the beginning of knowledge, not its end; the only use that can be made of it is to enable us to declare a common agreement with regard to first principles, and devote our attention to Knowledge, which is Life.

This agreement will not take place until Science has made these first principles so clear that they will become the common property of the world. This result cannot be reached until the ultimate signification of our most general (metaphysical) terms has been placed beyond dispute. When a term meaning time is used, we have a right to insist upon the

limits of that conception, and so with the term space. Thus armed with clear and definite ideas of the scope of language, the most ordinary intellect can expose the fallacies of the conventional metaphysicians, and the tortures to which these autocrats of our higher speculations have subjected common-sense minds for the past twenty-five centuries will happily cease.

To continue our narrative: Democritus declared Being to consist in an infinite number of small invisible bodies moving in the void,-these were the primary elements, and all production was caused by the change of relation among them. He accepted motion as something eternal, and did not attempt to explain it. Atoms, he said, being indivisible, must necessarily be self-existent, and all consists of Atoms and the Void.

The atomism of Democritus is a very profound speculation. In it he tried to distinguish between the ideas of force and those of weight, and of course did not succeed. Lewes, anxious to compare Democritus to Leibnitz, declares that the atoms of Democritus had no weight, only force; while on the same subject Zeller says: "Democritus supposed that all atoms are too small to be perceived by our senses; this he was compelled to assume because every substance perceptible to sense is divisible, changeable, and of determinate quality. But magnitude directly involves weight, for weight belongs to every body as such; and as all matter is homogeneous, it must equally belong to all bodies; -so that all bodies of the same mass are of the same weight. The proportion of weight of particular bodies is therefore exclusively conditioned by the proportion of their masses, and corresponds entirely with this; and when a large body appears to be lighter than a smaller one, this is only because it contains in it more empty space, and therefore its mass is really less than that of the other. Thus the atoms must have weight, and the same specific weight; but at the same time they must differ in weight quite as much as in magnitude. This doctrine is of great importance for the Atomic

system: texts which maintain the contrary are to be considered erroneous."

It is difficult to perceive what progress modern physicists, who regard matter as an ultimate fact, have made beyond this ancient theory.

CHAPTER III.

THE CLIMAX OF GREEK THOUGHT.

The Sophists-Socrates-Plato.

BEFORE attempting a description of the doctrines of Socrates, Plato, and Aristotle, which are looked upon as the climax of Greek thought, it will be well to call attention to the storm of common sense that swept over Greece just before and during the advent of these men. It was a general movement of dissatisfaction with the results of philosophic thought; a reaction which has often repeated itself since then. Its leaders are referred to in the writings of their opponents as Sophists; and as these writings constitute the chief literature of that epoch, our notions of the Sophists have been modelled by their bitter antagonists. The doctrines of the Sophists were the natural consequence of the decline of the first schools of philosophy. They were of use in bringing the different schools into comparison and showing the defects of each. Protagoras, the first and most accomplished of the Sophists, was born at Abdera. It is stated that Democritus instructed him in philosophy, but there is probably little truth in the statement, as Protagoras was older than Democritus; still it indicates a certain connection between the thought of the two philosophers. Protagoras endeavored to trace the origin of all conceptions to sensation. His doctrine was, that all thought is the same as sensation, and is limited by it; and that as all sensation is but relatively true, all knowledge is relative, and therefore imperfect. In the energetic mind of Protagoras these conclusions led to outright skepticism. It resulted in the for

mula: "Man is the measure of all things"; an epigram which expresses with wonderful clearness the doctrine of Kant and the great school of modern idealists. In tracing all thought to sensation, however, we have a forecast of modern psychology. The following translation from Sextus Empiricus is perhaps the best description extant of the psychological doctrines of Protagoras.

"Matter," says Protagoras, "is in a perpetual flux; whilst it undergoes augmentations and losses, the senses also are modified, according to the age and disposition of the body."

"The reasons of all phenomena (appearances) resided in matter as substrata; so that matter, in itself, might be whatever it appeared to each. But men have different perceptions at different times, according to the changes in the thing perceived. Whoever is in a healthy state perceives things such as they appear to all others in a healthy state, and vice versa. A similar course holds with respect to different ages, as well as in sleeping and waking. Man is therefore the criterion of that which exists; all that is perceived by him exists, that which is perceived by no man does not exist."1

It would be hard to find a simpler and more lucid expression of the Kantian theory of perception than this doctrine of Protagoras. From the speech of Callicles, in "Plato's Gorgias," we can gain an idea of the way in which the Sophists regarded philosophy.

"Philosophy is a graceful thing when it is moderately cultivated in youth; but, if any one occupies himself with it beyond the proper age, it ruins him; for, however great may be his natural capacity, if he philosophizes too long, he must of necessity be inexperienced in all those things which one who would be great and eminent must be experienced in. He must be unacquainted with the laws of his country, and with the mode of influencing other men in the intercourse of life, whether private or public, and with the pleas

1" Pyrrhon. Hypot.," p. 44. (Trans. by Lewes.)