Charles Darwin: The Descent of Man(1871)
Explanation and Analysis of the Document
In chapter XXI, Darwin offers a summary and conclusion of The Descent of Man. His chief conclusion is that “man is descended from some less highly organised form,” a conclusion he reaches by seeing natural phenomena as connected. One thing leads to another, and the direction of development tends to be toward greater organization, which proceeds in small steps by slight variation. The source of variation lies more in the constitution of the organism than in the surrounding conditions in which the organism develops. And the process, in humans as in other organisms, appears to be one in which individuals better fitted to their environment survive in greater numbers than those less well fitted.
When Darwin turns to the development of intellect, he is especially attentive to language: “As soon as the half-art and half-instinct of language came into use,” its action on the brain became one factor in the brain's further development. With...
Charles Darwin (Library of Congress)View Full Size