Happy Birthday, Thomas

Born May 4 in Ealing, England, in 1825, the man known as "Darwin's Bulldog" - Thomas Huxley. Huxley was a doctor and a highly respected scientist in 1856, when he went to visit his friend Charles Darwin, and Darwin explained to Huxley his theory of evolution. Darwin was by nature a reclusive person, a great writer but not a great public speaker. But Huxley enjoyed public debates, and engaged in many over the years. In one - with Archbishop Wilberforce - he said:

"I would rather be the offspring of two apes than be a man afraid to face the truth."

However, Huxley was more than a defender. He made many of his observations of his own and refined the theory. In particular, where Darwin had seen evolution as a slow, gradual, continuous process, Huxley thought that an evolving lineage might make rapid jumps, or saltations. As he wrote to Darwin just before publication of the Origin of Species, "You have loaded yourself with an unnecessary difficulty in adopting Natura non facit saltum [Nature does not make leaps] so unreservedly." (Punctured Equilibrium, anybody?) He also was the first to hypothesize that birds were descended from dinosaurs, a theory that has only recently been accepted by most paleontologists (T-Rex tasted like chicken???)

Huxley was a fine writer, clear and expressive. His most famous book, published in 1863, is Evidence on Man's Place in Nature. This book, published only five years after Darwin's Origin of Species, was a comprehensive review of what was known at the time about primate and human paleontology and ethology. In it, Huxley explicitly presented evidence for human evolution. Much has been learned since then, but the book is still eminently readable.

He also coined the word "agnostic," to describe his own religious idea that the only things worth believing in were things that could be directly observed in the world. His definition:

Positively the principle may be expressed: In matters of your intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect, do not pretend that conclusions are certain which are not demonstrated or demonstrable. That I take to be the agnostic faith, which if a man keep whole and undefiled, he shall not be ashamed to look the universe in the face, whatever the future may have in store for him.