ND   JMC : History of Medieval Philosophy / by Maurice De Wulf


468. Scientific Discoveries and their Bearing on Scholastic Philosophy. -- The controversies between the scientists and the Aristotelians form an epilogue to the decadence of scholasticism: unimportant in themselves, the episodes of these controversies have a considerable interest and significance owing to the circumstances of the age in which they occurred.

The great discoveries of Copernicus, Galileo, Kepler, Newton, Torricelli and Lavoisier effected a complete revolution in the sciences of astronomy, physics, chemistry and biology; whilst at the same time Descartes, Newton and Leibnitz were reconstructing the mathematical sciences on an entirely new basis. All this meant the destruction of the old theories in astronomical and general physics, as incorporated in the Middle Age synthetic conception of the Universe. For the Ptolemaic, geocentric system, Copernicus substituted the heliocentric system of astronomy. The telescope revealed stars travelling freely through the heavenly spaces, thus ruining the theory of solid celestial spheres. The elliptic orbits of the planets exploded the old notion of the perfection of circular movement. Above all, an ever-growing body of observations overthrew ail hitherto received ideas about the nature of the various heavenly bodies. Galileo discovered new stars in many of the constellations; in 1611 the telescope revealed spots on the sun's disc, and from their displacement he inferred the rotatory motion of the sun itself; he distinguished the phases of the planet Venus, thus experimentally confirming the predictions of Copernicus; the moon too revealed its mountains and its valleys; a little later it was proved to demonstration that the magnificent comet of 1618 was no atmospheric will-o'-the-wisp, but a heavenly body pursuing its path through the interplanetary regions of space. Now, if there are spots in the sun, the heavenly bodies are neither immutable nor perfect; if stars appear and disappear, they cannot be "ingenerabilia et incorruptibilia"; and if all those special privileges and prerogatives of the heavenly bodies, as compared with terrestrial substances, are only so many chimeras, the stars can have no influence on the fate and fortunes of sublunary life and change.

Then, in another direction, the thermometer revealed the fact that heat and cold are but different degrees of one and the same state of matter, and not contrary properties; the barometer proved that the atmosphere has weight; and thus down went the theories of the locus naturalis of the elements, their independent and autonomous movements, and the irreducible opposition of their qualities (295).

But those theories in astronomy, chemistry and Physics had been wedded for centuries to principles of general metaphysics and cosmology. Was not the lot of the latter, therefore, inseparably bound up with that of the former, and did not the overthrow of medieval science necessarily involve the destruction of medieval philosophy also?

No; not necessarily. And why? Because amid the ruins of medieval science there still stood erect and uninjured a sound and solid groundwork of observation and experience, quite sufficient to sustain the great organic and constitutional doctrines of scholasticism. These latter were still corroborated by elementary and unimpeachable facts of sense-experience: they had never depended, for their intrinsic truth and value, upon the worth of certain collateral postulates concerning the subject-matters of the special sciences: postulates, some of which had always rested on purely imaginary foundations (as, for instance, the postulate of the perfection of the heavenly bodies), and others on foundations that were at best exceedingly fragile (as, for instance, the theories of the locus naturalis, and of the conjunctions of opposite qualities in material things).

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