 A pressing issue has become that of identifying what is distinctively mathematical in mathematical explanations of scientific facts. Lange (2013c, 2017, 2018) has recently put forward a modal theory of explanation, according to which mathematical explanations of scientific facts act as constraints which have modal necessity stronger than causal necessity. As he puts it in Lange 2013c: “A distinctively mathematical explanation works by showing the explanandum to be more necessary (given the physical arrangement in question) than ordinary causal laws could render it. Distinctively mathematical explanations thus supply a kind of understanding that causal explanations cannot.” He calls many of these explanations “explanations by constraint” and distinguishes them from causal explanations and from “really statistical” explanations (for instance, but not exclusively, explanations by regression toward the mean; for more on statistical explanations see Lange 2013b). Craver and Povich 2017 argue that Lange’s theory of explanation by constraint (and even his account of “really statistical” explanations) is flawed, for it fails to account for the directionality of the explanatory relation in distinctively mathematical explanations. Pincock 2015a proposes to account for mathematical explanations in science by appealing to a notion of “abstract explanation” considered as one which involves “an appeal to a more abstract entity than the state of affairs being explained.” Pincock defends an ontic account of explanation based on dependence relations that are different from causal relations. Abstract explanations classify systems, as opposed to emphasizing the modal character of the system’s properties (see also Pincock 2018). Baron 2017 revamps the deductive-nomological model to account for mathematical explanations of scientific facts by using an informational account of relevance logic to capture the dependence relation between mathematical facts and physics facts. 