The question of knowledge versus competency in contemporary curricula is controversial. In this article we endeavour to show that the controversy has much to do with the way society is conceptualized as either a class differentiated or a function differentiated society. We examine Michael Young's input to the curriculum debate concerning the question of knowledge with the aim of showing that his knowledge-centred approach, which considers class and status to be the main structuring influences on society, does not address the problems captured by a function differentiated perspective (society differentiated in function systems). We demonstrate that to understand knowledge adequately in the context of the challenges of a modern function differentiated society it is better conceptualized within a competency context. Finally, we argue that criticism from a class perspective does not adequately target specific problems arising from function differentiation.