 Another rich discussion of an example of explanation from mathematical practice has been offered in Pincock 2015b. Pincock focuses on the proof of the impossibility of solving a quintic equation by radicals. Several proofs are looked at and the proof given in terms of Galois theory is singled out as explanatory. Pincock is especially interested in the abstract nature of the explanation, which in his account functions by appeal to an entity that is more abstract than the subject matter of the theorem itself. The proof of the result given in terms of Galois theory, according to Pincock, ‘is an explanatory proof because it invokes a special sort of ontological dependence between distinct mathematical domains.’ (p. 3) As often with accounts that end up appealing to grounding of various sorts, Pincock also does not think that the dependence in question can be explicated in simpler terms.