While it's easy to simply define these terms — moralism is about the intrinsic value of actions, regardless of their consequences; pragmatism is about evaluating actions according to their outcomes — it's more difficult to identify these principles in actual thought. A moralist can justly point out that intrinsically bad actions often have bad results, and because it always (or almost always) has a bad result, a pragmatist might say determine that some action was itself bad. In the trivial case, moralism and pragmatism become identical: saying an action is intrinsically bad to some degree is to say that it has bad results to that degree. We need to apply more subtlety to discern these approaches in practice.
It's often helpful to look at edge cases. In an edge case, a moralist will condemn or praise an action even if he acknowledges it has, as best he can tell, the opposite effects. Similarly, a pragmatist will condemn or praise an action even if our moral intuition, applied directly to the action, is the opposite of our evaluation of its effects.
A case in point is Rabbi Moshe Averick's recent article, Pedophilia Is Next On the Slippery Slope. Averick (interpreted with perhaps an excess of charity) makes the argument that even if we were to find that pedophilia had positive consequences, it would still be wrong. His article is full of straw men and lousy arguments, but we can see a thread of moralism in his underlying position. In contrast, if a pragmatist were to find that sexual contact between minors and adults had an overall benefit, he would be forced to admit that his moral intuition was mistaken. I do not believe that pedophilia is actually beneficial, but it's possible that I could change my mind; for the moralist, it's impossible by definition to change his mind, because the outcome is at best only of secondary importance.
Another case in point is Andrew Mellon's position during the Great Depression (as reported by Herbert Hoover):
Liquidate labor, liquidate stocks, liquidate the farmers, liquidate real estate... [Panic and depression] will purge the rottenness out of the system. High costs of living and high living will come down. People will work harder, live a more moral life. Values will be adjusted, and enterprising people will pick up the wrecks from less competent people.Mellon clearly had a moralistic view: there was at least an incorrect way of living, "high living", which had to be corrected even at the cost of "liquidating" the economic livelihood of millions of people.
Today's post by Paul Krugman has a telling paragraph about moralism in economics:
I don’t fully understand [the resistance among Very Serious People to lowering unemployment]. But a large part of it, it seems obvious, is the intense desire to see economics as a morality play of sin and punishment, where the sinners are, of course, workers and governments, not the bankers. Pain is not an unfortunate consequence of policies, it’s what is supposed to happen.An evolutionary view of social development helps explain why people adopt moralistic views. In an evolutionary view, our social development is the product of heritable random* variation of social ideas or mores and natural selection. Natural selection works against, it eliminates variations from the pool that can be inherited. Thus, we can say that people randomly develop moral attitudes towards actions themselves; some of these moral attitudes are selected against and eliminated; whatever remains forms the basis of the society's morality (and politics). Since the ideas were not generated intentionally and rationally, we tend to treat them with mystical reverence. In many societies, these ideas come directly from the gods. Moreover, we hold onto these ideas because of meta-evolution: a society cannot exist without some degree of inherent stability in the transmission (heritability) of social ideas. A society will not long survive if each new generation must reconstruct its social and moral ideas from scratch.
*i.e. their generation is uncorrelated with outcomes
Even a die-hard pragmatist such as myself must admit that moralism has some value. We cannot come anywhere close to predicting the consequences of every action; sometimes the best we can say about an action is that it seems to have worked in the past. To the moralist, moralism is an expression of knowledge: they know that some action is right or wrong independently of its outcome. In contrast, the pragmatic use of moralism is an expression of ignorance: some action seems intrinsically right or wrong because we don't know the consequences of acting differently. But we often do know the consequences, and to the pragmatist, knowledge of the consequences outweighs even the most established tradition.
It's important to understand this dimension of ethical thought to differentiate between trivial and substantive conservatism. Trivial conservatism is just the idea that "if it works, don't fix it." In contrast, a substantive conservative holds that those moral intuitions sanctioned by tradition (and, if we are cynical, justify his privilege) are inherently correct. I myself, not only a die-hard pragmatist but also a thoroughgoing radical, adhere to trivial conservatism. But I know what I mean by working and not working: if it doesn't work, we must fix it.