Charles Darwin (1809 – 1882) is the founder of modern biology, and one of the most influential intellectual figures of the 20th century. He is best known for his contributions to the science of evolution. He developed the theory of natural selection through struggle and published his work in On the Origin of Species. In this excerpt from Darwin’s autobiography he writes of how his work in evolution slowly eroded his religiosity. This section is from The Portable Atheist, Ed. Christopher Hitchens. The introduction to the reading was written by Hitchens.