Chapter 2 draws out the structural analogy between science and ethics: the idea that just as scientific theories can be underdetermined by the empirical data, so moral theories can be underdetermined by our considered judgments or intuitions. I start with the notion of a moral theory. I introduce what I take to be an independently plausible view that ascribes two functions to moral theories: accounting for our considered judgements or intuitions and explaining them. I then go into the details of both functions. I discuss the standard view of how theories are supposed to account for our considered judgements, the deductive principles model, and introduce two modifications. I then outline how the notion of grounding can be used to elucidate how many ethicists think of moral explanation. The second section is about the analogs of the data of scientific theories. I outline why I take these to be considered judgments or intuitions and why they need to be about particular cases. The third section considers two possible problems with the analogy, one stemming from the fact that ethicists also have intuitions about general principles, the other having to do with theory-ladenness.