The Modal Theory of Function Is Not about Functions

In a series of papers, Bence Nanay has recently put forward and defended a new theory of function, which he calls the 'Modal Theory of Function'. In this article, I critically address this theory and argue that it fails to fulfill some key desiderata that a satisfactory theory of function must comply with. As a result, I conclude that, whatever property Nanay's notion of function refers to, it is not the property having the function that is standardly attributed in science.