Henry Sidgwick's The Methods of Ethics is one of the most important and influential works in the history of moral philosophy. The Methods of Ethics clarifies and tackles some of the most enduring and difficult problems of morality. It offers readers a high-calibre example of analytical moral philosophy. This Element interprets and critically evaluates select positions and arguments in Sidgwick's The Methods of Ethics. It focuses specifically on Sidgwick's moral epistemology, his argument against common-sense morality, his argument for utilitarianism, his argument for rational egoism, and his argument for what he calls 'the dualism of practical reason', the thesis that utilitarianism and rational egoism are coordinate but conflicting requirements of rationality. Sidgwick's Ethics attempts to acquaint readers with the scholarly and theoretical debates relating to Sidgwick's theses, while providing readers with a greater appreciation of the depth and sophistication of Sidgwick's masterpiece.

Deontology is a theory about how we should act, morally speaking. It comes in several varieties, but all share certain doctrines, many of which are close to those found in the so-called 'common-sense morality' of the Western world. And all varieties are united in their opposition to consequentialism, a theory that, in its simplest form, tells us that we should always act so as to maximize impersonal value by bringing about the best consequences. This Element presents some of the different versions of deontology, including the views of W. D. Ross, and, to a lesser extent, Immanuel Kant. It defends certain deontological tenets, while challenging others, and contrasts them with consequentialism. Deontology and consequentialism are two of the main contenders in ethical theory, but virtue ethics is another, and it too is addressed (briefly), with an attempt to see it, in its most plausible form, as part of deontology.