The actual reality. For example whether H’ can have a corporeal manifestation or not. There is only one objective reality answer to that question. Either the Rambam is correct or those who believed otherwise are correct.
Ah, but I’m more concerned with how I’m supposed to act. And the torah is lo b’shomayim.
The title of apikores is not about making fun of them; its about knowing whether there is a mitzva to make fun of them, and if I can eat from their kashrus, etc.