This article offers a philosophical critique of Michael Young's notion of 'powerful knowledge', as found largely in his own but also in others' writings since 2009. The first part of the article focuses on the definitional connection that Young makes between 'powerful knowledge' and systematic relationships between concepts. It argues that most of the school subjects that Young sees as providing 'powerful knowledge' fall short on this requirement. It also comments on the place of educational aims and of everyday concepts in Young's thinking. The second part of the article draws attention to similarities and differences between Young's notion and the philosopher Paul Hirst's notion of 'forms of knowledge', claiming that Young's position is vulnerable to many of the critiques of Hirst's notion formulated between the 1960s and the 1990s.