The Principles of Psychology. Volume 1

Herbert Spencer used Darwinian theories to inform his philosophy; he contended that humans have evolved in a pattern of increasing complexity, driven by 'force,' the central principle of change. Many of Spencer's scientific ideas have since been disproven, and his philosophy has accordingly become less widely read than it once was. Nonetheless, such works as his ten-volume System of Synthetic Philosophy remain of great interest to philosophers and historians of scientific thought.