Moral disagreement is not only a philosophically interesting matter in its own right, but is also a highly important social and political issue. Historically, moral disagreement has often led to instability, conflict and persecution. It’s easy enough to see how a society of individuals with a consensus on important moral issues can forge a common life together, but it is more difficult to determine how cooperation is to be attained whilst disagreement on key matters persists. If we are to understand how best to face up to moral disagreement, it is vital that we get to grips with what exactly we are dealing with, and what options are feasible.
In this thesis, I articulate a particular conception of what moral disagreement involves, its extent, and what its root psychological causes are. I further demonstrate that this conception has important implications for a contemporary debate within liberal political theory. In so doing, I advocate a descriptive form of value pluralism, whereby individuals are typically committed to a range of distinct values which they implicitly take to have independent normative force. I suggest that individuals both across and within cultural groups weight such values differently, leading to fundamental moral disagreement.
This is explained by my proposed Two-stage Enculturated Affect (TEA) model of moral psychology, whereby values are cultural constructs which gain their perceived normative force through their relation to an agent’s affective dispositions. Such affective dispositions are the product of both shared and non-shared environmental influences, as well as our particular genetic endowment. They thus differ between individuals, leading to differences in value-weighting.
My account implies that moral disagreement is both inevitable and often a consequence of affective variation, rather than any defect in either disputant’s reasoning. This may present a problem for accounts of liberalism which rely on a consent-based account of political legitimacy. In the final part of my thesis, I show that my TEA model’s account of moral disagreement can be drawn upon to help reinforce a modified version of John Rawls’s political liberalism.
