"Astevism" is the phenomenon that people have when they do not believe that Steve McRae exists. This is usually do to the rather bizarre claim some have that they do not have any beliefs and as such that entails that the must not also believe that Steve exists. Thus they are Astevists.¹
After working past his existential crisis, Steve wrote about this very peculiar phenomenon in a blog:
¹ In the colloquial sensu lato sense of the word. In the sensu stricto sense it would be someone who believes Steve does not exist.