It is a basic assumption in the book that actors make ethical considerations in order to be able to act in accordance with reasons that they believe to be acceptable to everybody with sufficient insight and logical skills. Human beings have a fundamental obligation and inclination to be able to justify actions with rational, impersonal arguments. This assumption is explained in terms of impartiality and universalization with a special focus on themes highlighted in concentric circle theory and the concept of second-order impartiality. The basic point is that it is possible to be partial to relatives, friends, fellow citizens, etc. without renouncing the claim of impartiality: our own partiality is acceptable as long as we would accept similar partiality from others. In the following part of the chapter this idea of second-order impartiality is discussed in relation to (a) conceptions of international relations and obligations (realism, neighbourhood, and cosmopolitanism) and (b) intergenerational justice, both of which have become crucial for decisions on energy policy. The general aim of the chapter is to cultivate a conception of impartiality that can be both enlightening and critical in the study of ethics in practice – in this case, the development of energy policy over half a century.