This chapter and the succeeding one are concerned with the respective traditions of optimism and pessimism in relation to the international order, the former asserting that reform is both necessary and possible and the latter that reform is both unattainable and dangerous. For reasons of convenience, and in accordance with widespread practice, we may refer to these traditions as those of utopianism and realism. By way of caution, however, it should be pointed out that although there is extensive overlap between optimism and pessimism, on the one hand, and utopianism and realism, on the other, the two are not absolutely identical. Optimism reflects a faith that progressive change is possible, whereas utopianism, in its strict sense, pertains to the pursuit of the unattainable ideal. Likewise, pessimism is a denial of the possibility of progress, whereas realism, again in its strict sense, means the harmonious blending of practical activities with an extant reality without necessarily asserting that reality is itself unchanging. Nonetheless, for present purposes, we shall refer to utopianism as the ideological impetus to reform of the international order and to realism as the main source of resistance.

It is, however, important to emphasise that while utopian and realist thought diverge fundamentally as to the possibility of reforming the international order, much utopian argument is located within the same paradigm as realism.