With the growth of Modern Science in the eighteenth century full discussion of the Idea was revived, and from a hundred and fifty years ago Evolution was discussed throughout educated Europe. During the nineteenth century a great mass of evidence was accumulated in its favour, and to-day it is almost (but not quite) universally held by specialists who have authority to speak upon such matters. It is true that the process Organic Evolution may have taken becomes more and more doubtful as modern research and debate advance. Have the various species of Plants and Animals branched out from one original living cell or from many? It is uncertain. Have the new origins of life appeared in succession and separately at long intervals of time? It is possible or probable. Is transformism, that is, the change of one fully-developed mature and complex type into another, true? For instance, could a Reptile have changed into a Bird? Half a lifetime ago nearly everybody answered “Yes.” To-day—especially since the great work of Vialleton—more and more people are answering “No.” These and any number of other doubts and criticisms—and some disproofs—have arisen in our time, though Evolution in the widest sense of the word—that is, the doctrine that living things are genetically connected, is still the main doctrine taught and held in Biology. But Evolution in general is not the point. It involves no fundamental issue. It clashes with no theology or philosophy, unless we dignify by those terms an attachment to pictures of ready-made beasts in the family Bible. It is when men come to discuss _how_ the difference between varying types arose that we enter at once upon a quarrel between opposing philosophies, Christian and anti-Christian. No Catholic, nor indeed any man possessed of a philosophy, would trouble himself much over the confirmation or disproof of Evolution. Evolution simply means continuous growth; a tree growing from a seedling is an example of evolution; growth is the universal phenomenon apparent in ourselves and all organic life around us, and to discover it generalized is no shock, but rather an extension of the obvious. But when we come to ask _how_ and _why_ the vast variety of living things past and present grew and differentiated as they did: whether a Spirit is at work or no: whether the process be intended or motiveless—_then_ the essential quarrel is engaged between those for whom the Universe is blind and those who see it to be the work of God. That quarrel, which had long been acute in the general field of philosophy, became acute in the particular field of Biology in the late middle of the nineteenth century—over sixty years ago.