Morality, Health, and Science

In our last discussion of morality and science, an interesting argument was raised in the comments (by rbd and then in more detail by Ben Finney), concerning an analogy between morality and health. Sam Harris has also brought it up. It's worth responding to because it (1) sounds convincing at first glance, and (2) has exactly the same flaw that the morality-as-science argument has. That's what a good analogy should do! If I can paraphrase, the argument is something like this: "You say that morality isn't part of science because you don't know what a `unit of well-being' is -- it's not something that could in principle be measured by doing an experiment. But one could just as easily say that you don't know what a `unit of health' is, and therefore medicine isn't part of science. The lack of some simple measurable quantity is a simplistic attack against a ...