Part of the interest in explaining why political disagreement is so intractable is to arrive at some assessment of the prospects for resolving it. In the introduction I distinguished between contestability and imperfection conceptions of how we should explain the intractability and pervasiveness of political disagreement. According to the imperfection conception, political disputes could in principle be settled to the satisfaction of any reasonable person who has the time and patience, and is able to apply the laws of logic fully and correctly; the contestability conception denies this because it holds that the rational constraints which govern the application of key political terms permit a range of different political viewpoints. The imperfection conception might seem to be inherently more optimistic than the contestability conception about the prospects of achieving a consensus without the use of coercive or manipulative means. But that appearance is merely superficial: defenders of the imperfection conception may with perfect consistency express deep scepticism about the possibility of rationally resolving political disputes in practice. Optimism is appropriate within the imperfection conception only if the barriers to rational consensus are regarded as removable; and lack of clarity, vested interests, the role of passion in clouding the perception of moral and political truth, limited human ability or the sheer difficulty in arriving at it given the complexity of the moral and political world, might be thought to place insuperable obstacles in the way of achieving a consensus on moral and political matters in practice.