In our religious moods, we may speak, as Theodore Parker did, of the universe as a “handful of dust which God enchants,” or we may speak of it, as Goethe did, as “the living garment of God”; but as men of science we can see it only as a vast complex of forces, out of which man has arisen, and of which he forms a part.  We are not to forget that we are a part of it, and that the more we magnify ourselves, the more we magnify it; that its glory is our glory, and our glory its glory, because we are its children.  In some way utterly beyond the reach of science to explain, or of philosophy to confirm, we have come out of it, and all we are or can be, is, or has been, potential in it.

IX

The evolution of life is, of course, bound up with the evolution of the world.  As the globe has ripened and matured, life has matured; higher and higher forms—­forms with larger and larger brains and more and more complex nerve mechanisms—­have appeared.

Physicists teach us that the evolution of the primary elements—­hydrogen, oxygen, nitrogen, carbon, calcium, and the like—­takes place in a solar body as the body cools.  As temperature decreases, one after another of the chemical elements makes its appearance, the simpler elements appearing first, and the more complex compounds appearing last, all apparently having their origin in some simple parent element.  It appears as if the evolution of life upon the globe had followed the same law and had waited upon the secular cooling of the earth.

Does not a man imply a cooler planet and a greater depth and refinement of soil than a dinosaur?  Only after a certain housecleaning and purification of the elements do higher forms appear; the vast accumulation of Silurian limestone must have hastened the age of fishes.  The age of reptiles waited for the clearing of the air of the burden of carbon dioxide.  The age of mammals awaited the deepening and the enrichment of the soil and the stability of the earth’s crust.  Who knows upon what physical conditions of the earth’s elements the brain of man was dependent?  Its highest development has certainly taken place in a temperate climate.  There can be little doubt that beyond a certain point the running-down of the earth-temperature will result in a running-down of life till it finally goes out.  Life is confined to a very narrow range of temperature.  If we were to translate degrees into miles and represent the temperature of the hottest stars, which is put at 30,000 degrees, by a line 30,000 miles long, then the part of the line marking the limits of life would be approximately three hundred miles.