Nancy Cartwright has drawn attention to how explanations are actually given in mathematical sciences. She argues that these procedures support an antirealist thesis that fundamental explanatory laws are not true. Moreover, she claims to be be essentially following Duhem's line of thought in developing this thesis. Without wishing to detract from the importance of her observations, it is suggested that they do not necessarily require the antirealist thesis. The antirealist interpretation of Duhem is also disputed. It is argued that Duhemian points, often understood antirealistically, bear a realist construal, and that antirealist interpretations of Duhem typically run into problems of consistency or of reducing his position to absurdity.