According to the orthodox view, it is impossible to know how different people's preferences compare in terms of strength and whether they are interpersonally comparable at all. Against the orthodox view, Donald Davidson (1986, 2004) argues that the interpersonal comparability of preferences is a necessary condition for the correct interpretation of other people's behaviour. In this paper I claim that, as originally stated, Davidson's argument does not succeed because it is vulnerable to several objections, including Barry Stroud's (1968) objection against (...) all transcendental arguments of a 'strong' kind. However, I argue that Davidson's strategy can still achieve results of anti-sceptical significance. If we reformulate Davidson's argument as a 'modest' transcendental argument and if we embrace an 'internal' account of epistemic justification, it is in fact possible to have at least justified beliefs about how different people's preferences compare in terms of strength and about their interpersonal comparability. (shrink)