ON ASTRONOMY
INTRODUCTION
The science of astronomy, in its history from the great period of Greece down to the dark ages, furnishes almost as complete a spectacle of decay as does geometry. It is quite certain “that Aristarchus taught the annual motion of the earth around the sun, and both he and Seleukus taught the diurnal rotation of the earth,”[264] but the general scientific development of the age was not sufficient to assimilate this advanced theory, and astronomers went back to a geocentric universe. Strange to say, the later rise of practical astronomy at Alexandria, and the development of pure mathematics, did not secure a return to the more advanced theory, the efforts of the later astronomers being devoted, not to a reconsideration of the fundamental theses of the subject, but to putting the geocentric theory on a secure mathematical basis. The greatest of these astronomers, Ptolemy (second century A.D.), left in his Syntaxis a comprehensive summing up of mathematical astronomy.
Among the Romans no scientists arose to assimilate the results of the work of the Greeks, and sound ideas as to the form of the universe were rare even in the most intelligent circles. Since systematic observation was not practiced, and a knowledge of the higher mathematics did not exist among the Romans, their astronomy was a matter of tradition and authority. Therefore upon the acceptance of Christianity and the realization that there was a conflict between the Greek and the Hebrew cosmologies, it was a comparatively easy matter to accept the Scriptures instead of the secular writers as the source of authority.
In Isidore’s ideas on cosmology a curious inconsistency appears. On the one hand, he shows that he regards the words of the Scripture as the final authority, and he frequently gives expression to primitive notions in accord with the Hebrew cosmology. On the other hand, he displays a greater liberality than is shown by his predecessor, Cassiodorus, or by any other Christian writer in the Latin language up to his time, in borrowing from the pagan writers on astronomy. The explanation of this may be that it was a natural reaction from dogmatic narrowness, made possible for him by the favorable conditions offered by contemporary Spain; but the more probable supposition is that his natural vagueness of mind and lack of critical power enabled him to be much more liberal in effect than he in reality would have wished to be.[265]
Another feature of Isidore’s De Astronomia that deserves notice is his attitude toward the forbidden science of astrology.[266] He denies a fundamental assumption of the science, namely, that Mercury and Venus, for example, have as planets an influence analogous to their characters in mythology, and he asserts that the names of the planets and fixed stars, as used in astrology, have no validity. This was vigorous reasoning for the dark ages, and to all appearance it completely cut away the foundation of astrology.[267] Nevertheless Isidore believed that astrology had some truth—the magi who announced the birth of Christ were, he believed, astrologers—but this truth arose “out of a deadly alliance of men and bad angels.” His attitude, then, seems to be that astrologers may forecast the future, but that their ability to do so depends on the assistance of demons, and that the drawing up of nativities is merely a pretence to cloak this partnership.
Little is known of astronomy as a subject in the Roman schools. It no doubt formed part of the curriculum, but apparently no text-book was produced between the time of Varro and that of Martianus Capella. The three school treatises of late Roman and early medieval times, written by Capella, Cassiodorus, and Isidore, were all the work of educational encyclopedists from whom nothing of a scientific character could be expected.
EXTRACTS
Book III, Chapter 24. On the name of astronomy.
1. Astronomy is the law of the stars, and it traces with inquiring reason the courses of the heavenly bodies, and their figures, and the regular movements of the stars with reference to one another and to the earth.