Existence of an ultimate, inscrutable, unanalyzable "Subject" as opposed to the "Object" world, implying an entity beyond scientific study.
I should probably start by explaining the words "Subject" and "Object". Subject is the self-referential observer of phenomena. Object is everything that is amenable to observation.
Is the Subject, which is single and the source of all observations, be beyond observation, logic and experiment? As someone said, "How can one study that by which everything else is studied? How can one observe the observer?"
Now, I am not talking about the mind. There is this self-referential awareness beyond the mind, and from which the mind starts up.