extinct volcanoes on the moon, or resolve spots of nebulous cloud into
clusters of blazing suns; it is that in every scientific theory we frame
by indirect methods visual images of things not present to sense. With
our mind's eye we see atmospheric convulsions on the surfaces of distant
worlds, watch the giant ichthyosaurs splashing in Jurassic oceans,
follow the varied figures of the rhythmic dance of molecules as chemical
elements unite and separate, or examine, with the aid of long-forgotten
vocabularies now magically restored, the manners and morals, the laws
and superstitions, of peoples that have ceased to be.[9] And so in art
the wonderful printing-press, and the engine that moves it, are the
lineal descendants through countless stages of complication, of the
simple levers of primitive man and the rude stylus wherewith he engraved
strange hieroglyphs on the bark of trees. In such ways, since the human
phase of evolution began, has the direct action of muscle and sense been
supplemented and superseded by the indirect work of the inquisitive and
inventive mind.




VIII.

Growing Predominance of the Psychical Life.


Let us note one further aspect of this mighty revolution. In its lowly
beginnings the psychical life was merely an appendage to the life of the
body. The avoidance of enemies, the securing of food, the perpetuation
of the species, make up the whole of the lives of lower animals, and the
rudiments of memory, reason, emotion, and volition were at first