A History of Science-1 [50]
not know, but the writers of a later time have preserved a tradition regarding a belief of Xenophanes that perhaps entitles him to be considered the father of geology. Thus Hippolytus records that Xenophanes studied the fossils to be found in quarries, and drew from their observation remarkable conclusions. His words are as follows: "Xenophanes believes that once the earth was mingled with the sea, but in the course of time it became freed from moisture; and his proofs are such as these: that shells are found in the midst of the land and among the mountains, that in the quarries of Syracuse the imprints of a fish and of seals had been found, and in Paros the imprint of an anchovy at some depth in the stone, and in Melite shallow impressions of all sorts of sea products. He says that these imprints were made when everything long ago was covered with mud, and then the imprint dried in the mud. Further, he says that all men will be destroyed when the earth sinks into the sea and becomes mud, and that the race will begin anew from the beginning; and this transformation takes place for all worlds."[7] Here, then, we see this earliest of paleontologists studying the fossil-bearing strata of the earth, and drawing from his observations a marvellously scientific induction. Almost two thousand years later another famous citizen of Italy, Leonardo da Vinci, was independently to think out similar conclusions from like observations. But not until the nineteenth century of our era, some twenty-four hundred years after the time of Xenophanes, was the old Greek's doctrine to be accepted by the scientific world. The ideas of Xenophanes were known to his contemporaries and, as we see, quoted for a few centuries by his successors, then they were ignored or quite forgotten; and if any philosopher of an ensuing age before the time of Leonardo championed a like rational explanation of the fossils, we have no record of the fact. The geological doctrine of Xenophanes, then, must be listed among those remarkable Greek anticipations of nineteenth -century science which suffered almost total eclipse in the intervening centuries. Among the pupils of Xenophanes was Parmenides, the thinker who was destined to carry on the work of his master along the same scientific lines, though at the same time mingling his scientific conceptions with the mysticism of the poet. We have already had occasion to mention that Parmenides championed the idea that the earth is round; noting also that doubts exist as to whether he or Pythagoras originated this doctrine. No explicit answer to this question can possibly be hoped for. It seems clear, however, that for a long time the Italic School, to which both these philosophers belonged, had a monopoly of the belief in question. Parmenides, like Pythagoras, is credited with having believed in the motion of the earth, though the evidence furnished by the writings of the philosopher himself is not as demonstrative as one could wish. Unfortunately, the copyists of a later age were more concerned with metaphysical speculations than with more tangible things. But as far as the fragmentary references to the ideas of Parmenides may be accepted, they do not support the idea of the earth's motion. Indeed, Parmenides is made to say explicitly, in preserved fragments, that "the world is immovable, limited, and spheroidal in form."[8] Nevertheless, some modern interpreters have found an opposite meaning in Parmenides. Thus Ritter interprets him as supposing "that the earth is in the centre spherical, and maintained in rotary motion by its equiponderance; around it lie certain rings, the highest composed of the rare element fire, the next lower a compound of light and darkness, and lowest of all one wholly of night, which probably indicated to his mind the surface of the earth, the centre of which again he probably considered to be fire."[9] But this, like too many interpretations of ancient thought, appears to read into the fragments ideas which the words themselves do not warrant. There seems no reason to doubt, however, that Parmenides