The actual reality
We can only deal with belief as a practical matter. I need to know what to believe for myself, and for anyone whose chinuch I am responsible for, and I need to know which beliefs are outside of halachic acceptability for halachic purposes. I am not going to decide whether Shmuly Yanklowitz will go to Gan Eden or Gehinnom, but I do need to know whether I can drink his wine, allow him to speak in my shul, and whether he (or anyone with his beliefs) should be considered worthy of Jewish leadership. To these questions, the answer is a resounding “NO!”.
There is no greater reality than what the Torah wants us to believe.