 If ethics is widely regarded as the most accessible branch of philosophy, it is so because many of its presuppositions are self-evident or trivial truths: All human actions, for example, serve some end or purpose; whether they are right or wrong depends on an actor’s overall aims. At least for secularists, the attainment of these overall aims is thought to be a condition or prerequisite for a good life. What we regard as a life worth living depends on the notion we have of our own nature and of the conditions of its fulfillment. This, in turn, is determined, at least in part, by the values and standards of the society we live in. Personal ends and purposes depend in each case not only on reason, but also on the individual agents’ dispositions (i.e.their likes and dislikes, which determine their personal character). The attainment of these ends can also depend at least in part on external factors, such as health, material prosperity, social status, and even on good looks or sheer luck.