I take it that something of the sort Kvanvig says about understanding is correct:
The central feature of understanding, it seems to me, is in the neighborhood of what internalist coherence theories say about justification. Understanding requires the grasping of explanatory and other coherence-making relationships in a large and comprehensive body of information. One can know many unrelated pieces of information, but understanding is achieved only when informational items are pieced together by the subject in question. [Kvanvig, The Value of Knowledge and the Pursuit of Understanding: 192]
and
[U]nderstanding requires, and knowledge does not, an internal grasping or appreciation of how the various elements in a body of information are related to each other in terms of explanatory, logical, probabilistic, and other kinds of relations that coherentists have thought constitutive of justification. [ibid.: 192-3]
(My own view actually differs slightly from Kvanvig's in that I want to take understanding as fundamental and explain explanation in terms of it, rather than the other way around, but this is tangential to what I'm talking about here.) So, for example, someone who misunderstands evolutionary theory might think that humans evolved from chimpanzees, while someone who understands evolutionary theory will hold that both humans and chimps evolved from a common hominid ancestor. Broadly speaking then we might think that there are four states a person can be in: (i) understanding; (ii) misunderstanding; (iii) befuddlement (when a person's beliefs in a particular domain are largely incoherent); and (iv) simple non-understanding (when a person doesn't have any beliefs about a particular domain, coherent or otherwise). In this case, it seems that misunderstanding is a species of understanding: the person who beliefs that humans evolved from chimps grasps coherence-making relationships between a body of propositions. Now, a dissenter might just define understanding as the factive kind, but at the very least, misunderstanding shares all the distinctive features of understanding, while lacking factivity, and so the two are naturally grouped together as cognate phenomenon. If this is right, understanding is not a species of knowledge because truth is not a necessary condition for understanding.
