the discussion of force. "How this metamorphosis takes place—how a force existing as motion, heat or light, can become a mode of consciousness—how it is possible for aerial vibrations to generate the sensation we call sound, or for the forces liberated by chemical changes in the brain to give rise to emotion—these are mysteries which it is impossible to fathom."[1] By this it is seen how materialism teaches that the activities of matter, such as heat and light, are metamorphosed into consciousness; that aerial vibrations generate the sensation of sound, and that emotions are the forces in matter liberated by the chemical changes of the food we eat. Yet as execrably materialistic, idolatrous and profane as this may seem, it must be conceded that it is in harmony with the general evolutionary argument, which holds that the forces proper to matter, working upward, have evolved the higher forms of life. One is as true as the other.
The theory that mental forces are those of matter transferred or metamorphosed is frequently supported by the illustration that the human body is like a machine, the stomach being the furnace, and the food analogous to the fuel from
- ↑ Spencer, First Principles, p. 217.
