 Cohen sees this connection between infinitesimals and reality in the section of the Critique of Pure Reason that Kant called the Anticipations of Perception. In the Anticipations, Kant introduces the idea of magnitudes that can vary continuously from a finite magnitude to zero. He calls these continuously variable magnitudes intensive magnitudes. Kant argues that there is an important connection between continuously variable magnitudes, sensation, and reality. While Cohen thinks Kant’s concern with sensation is a mistake, he thinks the connection between continuously variable magnitudes – that is, infinitesimals – and reality is exactly right. The connection is this. For Cohen, mathematical natural science can represent real objects only if it represents them as having unique identity conditions. Those identity conditions are defined by unique locations in space and time. But, Cohen insists, the mathematical units that natural science uses to represent space and time must themselves be defined by appeal to infinitesimal magnitudes.