 We have already seen when discussing Kitcher and Friedman that the notion of understanding is tied to that of explanation. There has been recent work on mathematical and scientific understanding (see, for instance, Avigad 2008, de Regt and Dieks 2005, de Regt, Leonelli, and Eigner 2013, de Regt 2017). In connection to mathematical explanation, understanding has been discussed in Molinini 2011, Cellucci 2014, Delariviére et al. 2017.