In the first volume of his biography of John Maynard Keynes, Robert Skidelsky reports that in the late days of the 19th century, the senior professors of political philosophy at Cambridge University were worried about a serious matter. They sensed that religion was losing its influence over people’s lives, and they were concerned about the consequences. In the absence of hope for the pleasures of heaven and without fear of the tortures of hell, why would anyone do good? Why would anyone work hard? Why would anyone be honest? Why would people care about each other? If people didn’t feel that God was watching, why would they avoid committing an evil act that might go undetected or doing a good deed that might go unnoticed?
Being good academics, these professors quickly formed not one but two schools of thought. One group, the intuitionists, said that people would be good because they naturally know what good is, and that they would continue to allow this intuitive knowledge to guide their lives. That idea, which sounded quaint even at the time, did not catch on. Intuition is free. It involves no calculation. It cannot be analyzed. For obvious reasons, intuitionism did not attract the best young minds at Cambridge, or anywhere else. The idea has passed from the academic scene (though the geneticists are now beginning to have their suspicions). Modern universities do not have departments of intuition — at least any that they are willing to acknowledge.
The other group, the utilitarians, said that people would continue to do good in the absence of God’s watchful eye because they would see that it was in their interest to be good. After one (intuitive) leap, this idea did catch on. Suppose people calculated their interest locally. Suppose people were interested only in their own welfare. Suppose people were interested only in themselves. Would that lead them to do good? Clearly, it would. Careful consideration of their personal interest would reveal to people that bad behavior would ultimately lead to a world they would not like. On the basis of this calculation, they would therefore choose to do good. This idea sounded like a testable proposition bearing on an interesting and important question, and — not surprisingly, perhaps — it did attract bright young minds both at Cambridge and elsewhere, minds attracted to data, models and arcane calculations.