Aristotle the Master Mind of the Greeks.—While Aristotle and Plato sought to prove the same things, and agreed with each other on many principles of philosophy, the method employed by the former was exactly the reverse of that of the latter. Plato founded his doctrine on the unity of all being, and observed the particular only through the universal. For proof he relied on the intuitive and the synthetic. Aristotle, on the contrary, found it necessary to consider the particular in order that the universal might be established. He therefore gathered facts, analyzed material, and discoursed upon the results. He was patient and persistent in his investigations, and not only gave the world a great lesson by his example, but he obtained better results than any other philosopher of antiquity. It is generally conceded that he showed the greatest strength of intellect, the deepest insight, the greatest breadth of speculative thought, and the clearest judgment of all philosophers, either ancient or modern.
Perhaps his doctrine of the necessity of a final cause, or sufficient reason, which gives a rational explanation of individual things, is Aristotle's greatest contribution to pure philosophy. The doctrine of empiricism has been ascribed to Aristotle, but he fully recognized the universal, and thought it connected with the individual, and not separated from it, as represented by Plato. The universal is self-determining in its individualization, and is, therefore, a process of identification rather than of differentiation. The attention which Aristotle gave to fact as opposed to theory, to investigation as opposed to speculation, and to final cause, led men from a condition of necessity to that of freedom, and taught philosophers to substantiate their theories by reason and by fact. There is no better illustration of his painstaking investigation than his writing 250 constitutional histories as the foundation of his work on "Politics." In this masterly work will be found an exposition of political theories and practice worthy the attention of all modern political philosophers. The service given by Aristotle to the learning of the Middle Ages, and, in fact, to modern philosophy, was very great.
Aristotle was of a more practical turn of mind than Plato. While he introduced the formal syllogism in logic, he also introduced the inductive method. Perhaps Aristotle represented the wisest and most learned of the Greeks, because he advanced beyond the speculative philosophy to a point where he attempted to substantiate theory by facts, and thus laid the foundation for comparative study.
Other Schools.—The Epicureans taught a philosophy based upon pleasure-seeking—or, as it may be stated, making happiness the highest aim of life. They said that to seek happiness was to seek the highest good. This philosophy in its pure state had no evil ethical tendency, but under the bad influences of remote followers of Epicurus it led to the degeneration of ethical practice. "Beware of excesses," says Epicurus, "for they will lead to unhappiness." Beware of folly and sin, for they lead to wretchedness. Nothing could have been better than this, until people began to follow sensuality as the immediate return of efforts to secure happiness. Then it led to corruption, and was one of the causes of the downfall of Greek as well as the Roman civilization.
The Stoics were a group of philosophers who placed great emphasis upon ethics in comparison with logic and physics. They looked on the world from the pessimistic side and made themselves happy by becoming martyrs. They taught that suffering, the endurance of pain without complaint, was the highest virtue. To them logic was the science of thought and of expression, physics was the science of nature, and ethics the science of the good. All ideas originated from sensation, and perception was the only criterion of truth. "We know only what we perceive (by sense); only those ideas contain certain knowledge for us which are ideas of real objects." The soul of man was corporeal and material, hence physics and metaphysics were almost identical. There is much incoherency in their philosophy; it abounds in paradoxes. For instance, it recognizes sense as the criterion and source of knowledge, and asserts that reason is universal and knowable. Yet it asserts that there is no rational element in sense that is universal. It confuses individual human nature and universal nature, though its final result was to unite both in one concept. The result of their entire philosophy was to create confusion, although they had much influence on the practical life.
The Sceptics doubted all knowledge obtained by the senses. There was no criterion of truth in the intellect, consequently no knowledge. If truth existed it was in conduct, and thus the judgment must be suspended. They held that there was nothing that could be determined of specific nature, nothing that could be of certainty. Eventually the whole Greek philosophy went out in scepticism. The three schools, the sceptic, the Epicurean, and the stoic, though widely differing in many ways, agreed upon one thing, in basing their philosophy on subjectivity, on mind rather than on objective nature.
Results Obtained in Greek Philosophy.—The philosophical conclusions aimed at by the Greeks related to the origin and destiny of the world. The world is an emanation from God, and in due time it will return to Him. It may be considered as a part of the substance of God, or it may be considered as something objective proceeding from him. The visible world around us becomes thus but an expression of the God mind. But as it came forth a thing of beauty, so it will return again to Him after its mission is fulfilled. On the existence and attributes of God the Greeks dwelt with great force. There is established first a unity of God, and this unity is the first cause in the creation. To what extent this unity is independent and separate in existence from nature, is left in great doubt. It was held that God is present everywhere in nature, though His being is not limited by time or space. Much of the philosophy bordered upon, if it did not openly avow, a belief in pantheism. The highest conception recognizes design in creation, which would give an individual existence to the Creator. Yet the most acute mind did not depart from the assumption of the idea of an all-pervading being of God extending throughout the universe, mingling with nature and to a certain extent inseparable from it. In their highest conception the most favored of the Greeks were not free from pantheistic notions.
The nature of the soul occupied much of the attention of the Greeks. They began by giving material characteristics to the mind. They soon separated it in concept from material nature and placed it as a part of God himself, who existed apart from material form. The soul has a past life, a present, and a future, as a final outcome of philosophical speculations. The attributes of the soul were confused with the attributes of the Supreme Being. These conceptions of the Divine Being and of the soul border on the Hindu philosophy.
Perhaps the subject which caused the most discussion was the attempt to determine a criterion of truth. Soon after the time when they broke away from the ancient religious faith, the thinkers of Greece began to doubt the ability of the mind to ascertain absolute truth. This arose out of the imperfections of knowledge obtained through the senses. Sense perception was held in much doubt. The world is full of delusions. Man thinks he sees when he does not. The rainbow is but an illusion when we attempt to analyze it. The eye deceives, the ear hears what does not exist; even touch and taste frequently deceive us. What, then, can be relied upon as accurate in determining knowledge? To this the Greek mind answers, "Nothing"; it reaches no definite conclusion, and this is the cardinal weakness of the philosophy. Indeed, the great weakness of the entire age of philosophy was want of data. It was a time of intense activity of the mind, but the lack of data led to much worthless speculation. The systematic method of scientific observation had not yet been discovered.
But how could this philosophical speculation affect civilization? It determined the views of life entertained by the Greeks, and human progress depended upon this. The progress of the world depends upon the attitude of the human mind toward nature, toward man and his life. The study of philosophy developed the mental capacity of man, gave him power to cope with nature, and enhanced his possibility of right living. More than this, it taught man to rely upon himself in explaining the origin and growth of the universe and the development of human life. Though these points were gained only by the few and soon lost sight of by all, yet they were revived in after years, and placed man upon the right basis for improvement.