In the Metaphysical Foundations of Natural Science, Kant claims that perception of force through touch is fundamental to our knowledge of substance in space. However, he also holds that perception cannot have modal content. Causation is a modal notion, so how can Kant allow perception of causal force? In response to this puzzle, I provide a new reading of Kant’s theory of touch. Touch does not involve perception of the necessity of a cause, but it does involve awareness of the activity of our body in relation to other bodies. Human embodied activity has a hitherto unrecognized central role in Kant’s accounts of empirical cognition of substance in space, the science of such a substance, and the irreducibility of its causal forces.