The dominant sceptical challenge in contemporary moral philosophy comes from debunking arguments. These arguments claim that the causal (e.g. evolutionary) origins of our moral beliefs undermine their epistemic status. It would be an obvious worry for defenders of these arguments if they were to generalise to our mathematical beliefs. In this essay I trace the contours of the extensive recent work on this question. I focus on the implications of recently popular ‘explanationist’ readings of debunking challenges for the generalisation worry.