The question ‘What is mathematics?’ has been answered in numerous ways, each providing its contribution to the general understanding of the nature of mathematics. The perspective offered in the present note sees mathematics as a science of model building. To confirm that the situation with respect to computer science is not an isolated phenomenon, we shall begin in § 1 with an historical overview of the model building‐character of mathematics. Following this, in §2, we shall consider the example of computer science. In §3, observations concerning this view of mathematics are given.