>Basically, the laws of nature are written in calculus
Calculus is a tool that powers certain specific useful predictive models of our observations of nature in certain specific domains.
Having a mental model in which the laws of nature are related to calculus in some deeper fashion (or where calculus is always an appropriate tool to describe observations of nature) is likely to lead to some erroneous intuitions.
Basically, the laws of nature are written in calculus, which is more than a language, and we can use this to manipulate nature.