EVOLUTION—ITS MEANING
argument. No other type of evidence, moreover, is so convincing as the cumulative one. The question we are considering is not one of logic but one of fact. Logic, with its specialized branch, mathematics, adds nothing to our knowledge; its function is to clarify assumptions already accepted.
Accepting the fact of orderly change—universal in so far as we can trace the relations of cause and effect and of natural sequence—we face a more difficult problem: How are the changes brought about? Here we no longer find unanimity of opinion, for in the myriad of facts at our disposal no single man can master their prodigious range and their diverse aspects. A forest is not the same to a lumberman as to a landscape gardener. A primrose in a greenhouse is not the same as one by the river's brim. “The harvest of the quiet eye” is not that which is garnered by the reaper. The microscope and the telescope yield knowledge from different angles. But the lesson of all science is that whatever takes place in nature is natural; not “supernatural.” Indeed, to science “supernatural” is a meaningless word. It concerns either nothing at all or something not yet found out. We might say that the term “supernatural” can be applied only to a set of conceptions that are held by minds which have not learned that all facts of human experience are natural.
Much has been written as to the possible source of life in a lifeless world. It is easy to suppose some sort of “spontaneous generation” or “chemical transition.” That supposition follows the line of least resistance; it is said by some to be a “logical necessity.” Thus one sitting in his study may blithely construct “synthetic protoplasm” by “a juggling of words,” or by a combination of ideas drawn from physics and chemistry. To state facts in simple terms, life appears only in connection with carbon, oxygen, hydro-
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