What’s past is prologue.
—Shakespeare (The Tempest, 1623)
Those who cannot remember the past are condemned to repeat it.
Evolution is a name for the process of adapting to an environment. This is true of anything that can change, including ideas. Natural selection is a name for the process that allows organisms with genes to adapt to an environment. An environment may change by the movement of continental plates, new weather patterns, population pressure, or human ideas. Continents change relatively slowly; ideas can change quickly.
The human prologue begins with our evolution from ancestor species, in response to changes in our environment. Animals that walk upright appeared about two million ...