Enough has now been said about the speculations of the "early Greeks" to show the extravagance of Lord Macaulay's assertion that the discoveries of modern astronomy have placed the modern philosopher in no better situation to make safe deductions in natural theology than that occupied by the Hellenic philosophers from Thales to Plato. The evidences of design in the formation of the solar system--of that kind of design which acts in direct and specific exertions of a formative will--have been enormously multiplied by the discoveries of modern astronomy. Those discoveries, instead of leaving us to grope among theories which require the invention or imagination of facts, relate to facts that are demonstrated; and they tend in the strongest manner to establish the hypothesis of an infinite Creator, making laws to govern material objects, and then creating a system of objects to be governed by those laws. In a future chapter I shall endeavor to show why this hypothesis in regard to the solar system is most conformable to the rules of rational belief. Not to anticipate what will be said hereafter concerning the modern discoveries in anatomy and in comparative zoölogy, it is enough to say here that in the writings of the Greek philosophers, especially of Plato and Aristotle, we may discover what the Greeks knew or did not know, and may therefore compare their knowledge with what is now known. What was known about the human anatomy to the Greeks of Plato's time is probably pretty well reflected in his "Timæus," the celebrated dissertation in which he developed his theory of the Kosmos; for, although Plato in that superb philosophical epic made use of the organs of the human body for ethical and theological purposes, and did not make a special study of matters of fact, it is not probable that in his mode of using them he so far departed from the received ideas of his time respecting the human anatomy that his treatise would have been regarded by his contemporaries as an absurdity. Indeed, Mr. Grote considered that Plato had that anatomical knowledge which an accomplished man of his time could hardly fail to acquire without special study.[8] Moreover, even Galen, who came five centuries after Plato, and whose anatomical knowledge was far greater than could have been commanded in Plato's day, was wholly wrong in respect to the functions of some of the human organs. He agreed with Plato's ethical view of the human organism, but not in his physiological postulates. He considered, according to Mr. Grote, that Plato had demonstrated the hypothesis of one soul to be absurd; he accepted Plato's triplicity of souls, but he located them differently. He held that there are three "originating and governing organs in the body: the brain, which is the origin of all the nerves, both of sensation and motion; the heart, the origin of the arteries; the liver, the sanguifacient organ, and the origin of the veins which distribute nourishment to all parts of the body.