Argues that the core of the concept of knowledge is true belief plus some property indicative of true belief and that there is no detailed answer to the query ‘and what property is that?’ The Nozick–Dretske counterfactual analysis, Alvin Goldman's causal theory, reliabilism, and the justified true belief account are all good approximations to the concept of knowledge, for, in each case, there is justification for the addition(s) made to the minimal concept. This justification arises not so much from the concept of knowledge itself as from certain very general beliefs we hold about the world. Thus, when the conditions laid down in the minimal concept are satisfied, it will almost always be believed that the conditions of the above theories are satisfied too.
Keywords: Dretske, Goldman, knowledge, Nozick, reliabilism