We see about us daily transformations as stupendous as that of the evolution of man from the lower animals, and we marvel not.  We see the inorganic pass into the organic, we see iron and lime and potash and silex blush in the flowers, sweeten in the fruit, ripen in the grain, crimson in the blood, and we marvel not.  We see the spotless pond-lily rising and unfolding its snowy petals, and its trembling heart of gold, from the black slime of the pond.  We contemplate our own life-history as shown in our pre-natal life, and we are not disturbed.  But when we stretch this process out through the geologic ages and try to see ourselves a germ, a fish, a reptile, in the womb of time, we are balked.  We do not see the great mother, or the great father, or feel the lift of the great biologic laws.  We are beyond our depth.  It is easy to believe that the baby is born of woman, because it is a matter of daily experience, but it is not easy to believe that man is born of the animal world below him, and that that is born of inorganic Nature, because the fact is too big and tremendous.

What we call Nature works in no other way; one law is over big and little alike.  What Nature does in a day typifies what she does in an eternity.  It is when we reach the things done on such an enormous scale of time and power and size that we are helpless.  The almost infinitely slow transformations that the theory of evolution demands balk us as do the size and distance of the fixed stars.

No observation or study of evolution on a small scale and near at hand in the familiar facts of the life about us can prepare us for it, any more than lake and river can prepare us for the ocean, or the modeling of miniature valleys and mountains by the rain in the clay bank can open our minds to receive the tremendous facts of the carving of the face of the continent by the same agents.

We do not see evolution working in one day, or in a century, or in many centuries.  Neither do we catch the gods of erosion at their Herculean tasks.  They always seem to be having a holiday, or else to be merely toying with their work.

When we see a mound of earth or a bank of clay worn into miniature mountain-chains and canons and gulches by the rains of a season, we do not doubt our eyes; we know the rains did it.  But when we see the same thing copied in a broad landscape, or on the face of a state or a continent, we find it hard to believe the evidence of our own senses.  The scale upon which it is done, and the time involved, put it so far beyond the sphere of our experience that something in us, probably the practical, everyday man, refuses to be convinced.

The lay mind can hardly have any adequate conception of the part erosion, the simple weathering of the rocks, has played in shaping our landscapes, and in preparing the earth for the abode of man.  The changes in the surface of the land in one’s lifetime, or even in the historic period, are so slight that the tales the geologists tell us are incredible.