ABSTRACT In this paper we compare philosophical and contemporary psychological approaches to mental handicap. Careful comparison between the disciplines reveals major differences and indicates that much further work is needed which would be fruitful for both sides. The two disciplines concentrate on different questions: philosophy tends to look chiefly at mental handicap in relation to issues of personhood and is not very clear about what mental handicap is; psychology on the other hand is much more specific about mental handicap, but (...) shows little concern with critically examining value issues. Our main intention is to explore the different ways in which mental handicap is defined and seen as a class. We conclude that class definition embodies a significant normative component and a large element of social construction. To ignore this and attempt to make normative judgements on the basis of class membership is thus highly problematic. Since within philosophy, these normative issues are often discussed in terms of personhood, this category is also critically examined and the conclusion is reached that it too has normative and social components which can lead to ethically dubious judgements being made about ‘the mentally handicapped’. (shrink)