The central idea of values-based practice is that clinical judgements should accommodate 'dissensus' by concentrating on right processes rather than good outcomes. Dissensus, however, has a philosophical history in political theory, especially liberal political theory, which may provide further tools for values-based practice. But it is not without difficulty. Rawlsian political theory aims to limit dissensus by presupposing rational consensus. Agonistic liberalism, although more promising, still leaves the problem of how conflicting views can be understood without presupposing some basic shared agreement.