Page:Popular Science Monthly Volume 12.djvu/191

Rh considerations. These were now to be replaced by others of a more definite and solid kind, derived from physical science.

The starting-point of Christendom in the theory of evolution, for the Mohammedans had now ceased to philosophize, was the publication by Copernicus of the book "De Revolutionibus Orbium Celestium." In this the Pythagorean view of the emplacement of the solar system was revived. The way for this restoration had been prepared by such books as that of Cusa "On Learned Ignorance." He conceived of-the universe as a vast organism, the life of which is the breath of God, and which has neither centre nor circumference, but is infinite as its maker. Such views were largely prevalent in Italy, at that time the focus of infidelity, and there Copernicus had been. His work was followed by Kepler's great discovery of the three laws that bear his name.

After the invention of printing, the "Index Expurgatorius" of prohibited books had become essentially necessary to the religious Reign of Terror, and for the stifling of the intellectual development of man. The Papal Government, accordingly, established the Congregation of that Index.

It was very plain that the tendency of Kepler's discoveries was to confirm the dominating influence of law in the solar system, as well as to destroy geocentric and anthropocentric theories. It was, therefore, adverse to the Italian theological views, and to the current religious practices. Kepler had published an epitome of the Copernican theory. This, as also the book itself of Copernicus, was placed in the Index, and forbidden to be read.

The Reformation came. It did not much change the matter. It insisted on the Mosaic views, and would tolerate no natural science that did not accord with them. Nevertheless, under the shadow of the political power it shortly gathered, Newton's "Principia" was safely published. The two great powers into which Christendom was divided held each other in check. The sectarian divisions fast springing up in Protestantism found occupation in their contentions with each other. The bearing which Newton's book had upon those already condemned consisted chiefly in this—it gave indisputable reasons that Kepler's laws are a mathematical necessity. For the finger of Providence it substituted mechanical force. And thus the Reign of Law, that great essential to the theory of evolution, was solidly established.

But not alone did the discoveries of physical astronomy lead to these views. If the heavens were observed, the earth, also, was examined. There could no longer be any doubt that fossil remains were the relics of beings that were once alive, as Xenophanes in the old times, and Da Vinci and Palissy more recently, had affirmed—not mere lusus naturæ; that the earth's strata were not all of the same age; that in the oldest no fossils could be found; that there had been