Figure 1

These were the prevailing tides and currents of thought about life, until one man had the chutzpah, the vision, and the deep insights to weave together a huge set of separate clues into one magnificent tapestry. This man was Charles Darwin (figure 1 shows him late in life), and his grand unified conception has become humankind’s most inspiring nonmathematical theory. Darwin has literally transformed the ideas on life on Earth from a myth into a science.

The first edition of Darwin’s book On the Origin of Species was published on November 24, 1859, in London, and biology was changed forever on that day. (Figure 2 shows the title page of the first edition; Darwin referred to it as “my child” upon publication.) Before we examine the central arguments of The Origin, however, it is important to understand what is not discussed in that book. Darwin does not say even one word either about the actual origin of life or about the evolution of the universe as a whole. Furthermore, contrary to some popular beliefs, he also does not discuss at all the evolution of humans, except in one prophetic, optimistic paragraph near the end of the book, where he says, “In the distant future I see open fields for more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by graduation. Light will be thrown on the origin of man and his history.” Only in a later book, The Descent of Man and Selection in Relation to Sex, which was published about a dozen years after The Origin, did Darwin decide to make it clear that he believed that his ideas on evolution should also apply to humans. He was actually much more specific than that, concluding that humans were the natural descendants of apelike creatures that probably lived in trees in the “Old World” (Africa):

We thus learn that man is descended from a hairy, tailed quadruped, probably arboreal in its habits and an inhabitant of the Old World. This creature, if its whole structure had been examined by a naturalist, would have been classed among the Quadrumana [primates with four hands, such as apes], as surely as the still more ancient progenitor of the Old and New World monkeys.