 Supposing that understanding cannot be transmitted by testimony, there are a few explanations for why this might be the case. For one, Zagzebski argues that the kind of “seeing” or “grasping” that seems integral to understanding is something a person can only do “first hand”—it cannot be inherited from anyone else (Zagzebski 2008: ch. 6). For another, and according to Hills, if we agree that understanding is a skill or ability, then understanding will be difficult or impossible to transmit because skills and abilities in general are difficult or impossible to transmit (Hills 2009, 2020). It is therefore a specific case of a more general phenomena.