A friend of mine who is medical school and, I gathered, taking a medical ethics course, asked for recommendations for readings to help her get a better feel for the main schools of thought in moral philosophy. She's a science-y person who has chosen to go into a field that involves dissecting dead bodies in school, and who registered a bit of puzzlement about the fuzzy intuition-mongering involved in her class's discussion of the “trolley problem,” so I had that in mind. I thought other's might be interested. So here, spiffed up a bit, is what I wrote. If you have good or, better, better recommendations, then please sock it to the comments.
For intro to ethics, one of my favorite books is Fred Feldman's Introductory Ethics, which is very clear and very rigorous. It's pretty dated (1978), but still good for getting a feel for the variety of ethical approaches, and the main objections to them. I hate most intro ethics books, but I don't hate this one.
For a good, cheap overview of the major ethical positions read these article in the Stanford Encyclopedia:
» Virtue ethics
» Natural law ethics
» Hume's moral philosophy
» Adam Smith's moral philosophy (in the 18th century Scottish philosophy entry.)
» Kant's moral philosophy
» Egoism (which I can't believe I forgot in the e-mail!)
I incline toward some kind of Hume/Smith position …
There is now a whole literature on the way intution works in thought experiments like the trolley problem. Scroll down Joshua Greene's page for his neuro-imaging work on people doing the trolley thought experiment. You can use this to blow the mind of your medical ethics class [or whomever] with your intellectual sophistication and moral-scientific with-it-ness!
Moral psychology is starting to take off as a field with some actual scientific teeth. Look at Jonathan Haidt's stuff.
Here is a book that I have yet to read by someone whose work I like that gives something like a scientific case for an updated Scottish sentimentalism:
» Sentimental Rules : On the Natural Foundations of Moral Judgment, by Shaun Nichols.
I've also been looking forward to reading this:
» Lack of Character : Personality and Moral Behavior, by John Doris
And I have read some of this and like it:
» Natural Ethical Facts : Evolution, Connectionism, and Moral Cognition, by William Casebeer
But all that's just if you want to get out on the cutting edge of empirically serious approaches to ethics. (And now my laxity in getting around to all these is getting to me.)
And here are some late-breaking additions:
I forgot to mention Lawrence Hinman's Ethics Update site, which has a lot of good intro ethics resources.
Oh! And don't forget Ayn Rand. That's where I started, for what that's worth. In my opinion, “Causality Versus Duty” (in Philosophy: Who Needs It?) makes more sense than “The Objectivist Ethics” (in The Virtue of Selfishness), although the latter is rather richer. Why not read my old review of Tara Smith's Viable Values, which may be the best academic treatment of Randian ethics. (Wow, I cannot say that I like the new TOC website design.) Here's the ARI's Ayn Rand reading list. The order makes sense, but feel free to skip the novels if you don't want to read a novel.