There are 54 volumes in the Great Books of the Western World series edited by Robert Maynard Hutchins and Mortimer Adler. Charles Darwin's writings are found in Volume 49 and Sigmund Freud has the last word in Volume 54. Some people may take these two intellectual giants for granted and others may doubt their sanity, but all must admit that Darwin's and Freud's inclusion with the likes of Plato, Copernicus, Chaucer, Shakespeare, and Newton counts for something. Darwin and Freud have much in common, but from the perspective of this book, one shared idea stands out: Humankind is something less than divine. To put it even more strongly, humans are very much like animals. Pointing out our irrationality is Freud's major contribution. He reminds us that our major motives derive from irrational sex and aggression urges which often cause us to make bad decisions and to misbehave. If you doubt the influence of sex and aggression motives, just turn on the TV tonight.

When these urges lead us to irrational behavior, we frequently excuse ourselves by proclaiming “I'm only human.” The idea of our inherent irrationality is very much ingrained in us. Darwin says that we're very much like animals and Freud says that we are driven by unconscious motives that make life really interesting but also very troublesome. One can expect only so much from our species; we are, after all, only human.