 A contextualist and pluralist account argues that understanding is a legitimate aim of science that is pragmatic and not necessarily formal, or a subjective psychological by-product of explanation (De Regt and Dieks 2005). In this view explanatory understanding is variable and can have diverse forms, such as causal-mechanical and unification, without conflict (De Regt and Dieks 2005). In the same spirit, Salmon linked unification to the the epistemic virtue or goal of explanation and distinguished between unification and causal-mechanical explanation as forms of scientific explanatory understanding (Salmon 1998). 