 This argument relies on a highly controversial principle about how an explanation of why something is a value must work — a very similar principle to that which was appealed to in the argument that intrinsic value must be an intrinsic property [section 2.1.1]. If this principle is false, then an explanatory theory of why both pleasure and knowledge are values can be offered which does not work by subsuming them under a further, more fundamental value. Reductive theories of what it is to be a value satisfy this description, and other kinds of theory may do so, as well (Schroeder [2005]). If one of these kinds of theory is correct, then even pluralists can offer an explanation of why the basic values that they appeal to are values.