  It might seem odd to suggest that we can come to know things about morality by using scientific methodology. Empirical methods are all, ultimately, grounded in an epistemology of observation. But, as Gilbert Harman (1977, Ch. 1) famously argued, it does not seem that we can observe moral facts in anything like the same way that we can observe other kinds of natural facts. It’s rather obvious how we can have empirical knowledge of natural properties such as redness or roundness; they are directly observable. But goodness doesn’t seem to be directly observable, and that looks like an important disanalogy between moral properties and natural properties.