Last night Diana Hsieh of Philosophy in Action interviewed Craig Biddle about common mistakes people make in thinking about ethics. The full podcast of the hourlong interview is now available. Discussion encompassed "people's wrong ideas about ethics, including ethics of duty, pragmatism, religious ethics, [and] collectivism."
For Biddle's systematic treatment of ethics, see his book, Loving Life: The Morality of Self-Interest and the Facts that Support It.