 Keith Lehrer employs the concept of coherence in his definition of justification, which in turn is a chief ingredient in his complex definition of knowledge. According to Lehrer, a person is justified in accepting a proposition just in case that proposition coheres with the relevant part of her cognitive system. This is the relational concept of coherence alluded to earlier. In Lehrer (1990), the relevant part is the “acceptance system” of the person, consisting of propositions to the effect that the subject accepts this and that. Thus, “\(S\) accepts that \(A\)” would initially be in \(S\)’s acceptance system, but not \(A\) itself. In later works, Lehrer has emphasized the importance of coherence with a more complex cognitive entity which he calls the “evaluation system” (e.g., Lehrer 2000 and 2003).