For ages men believed that the earth was the center of the universe. Proceeding upon this assumption, they developed a theory of astronomy, known as the Ptolemaic, which argued that the moon, the sun, the fixed stars, and each of the planets were located in different "crystalline spheres" revolving at different rates of speed around the earth as a center. Thus they tried to account for the varying movements of the different heavenly bodies. Soon after this hypothesis was developed, the phenomenon known as the retrograde motion of the planets was observed. Trying to explain this, the supposition of "cycles and epicycles" was added to the theory, until the Ptolemaic astronomy became a maze of complexity, and failed even then, as admitted by its adherents, adequately to account for the observed phenomena of planetary motion.
At last it occurred to Copernicus and Galileo to cease regarding the earth as the center of the universe or of the solar system, and to fix upon the sun as the center. Very soon the fundamentals of our present system of astronomy were established, the Ptolemaic system was thrown away as worthless, to be regarded in the future as one of the curiosities of human belief. It was soon discovered that the so-called retrograde motion of the planets is only apparent; that the appearance results because we are viewing the planets not from the sun which is the center of their revolution, but from the earth, which is itself a planet revolving around the sun in a different orbit and at a different rate from all the rest. Thus the grotesque labyrinth of supposed crystalline spheres, cycles, and epicycles was wholly explained away and all the tangles of apparent motion were adequately accounted for.
For ages men have believed that sense testimony, other names for which are "self," "the carnal mind," "the flesh," is the prime center, or at least one of the important and authoritative means of gaining knowledge about the universe and about man. Proceeding upon this assumption, systems of philosophy and theology have been wrought out, which have become increasingly complex and contradictory and which are in many directions as far from an adequate explanation or solution of the problems of life as at the start. The problem of evil has vexed all the philosophers, even as the problem of the retrograde motion of the planets did the astronomers. Evils have multiplied and diseases and sins have increased in kind and number. Apparent gains in some directions have been, to a large extent, offset by losses in other directions. The whole process has not been much better than a treadmill performance, though it must be conceded that enough of the light of true Christianity has dawned upon the human race to result in some measure of progress. But by those who cling to sense testimony as one of the fundamental avenues to knowledge, nothing like an adequate theory of life has been evolved. Working from this basis, "he that increaseth knowledge increaseth sorrow." Working from this standpoint men are "ever learning, and never able to come to the knowledge of the truth." This is because sense testimony, the carnal mind, "is enmity against God: for it is not subject to the law of God, neither indeed can be;" because "the flesh lusteth against the Spirit [God], and the Spirit against the flesh: and these are contrary the one to the other." God is the sole creator and the sole governor of all, and sense testimony, which is enmity to Him, can of course give no true or reliable information about His universe or about His children.
