It is notable that intuitions of transcendence resemble intuitions of free will. Both are strong if elusive, and quite unsupported apart from the felt intuition itself. Perhaps the underlying reasons in both cases are the same.
Our sense of free choice is the fully determined sensation of being at the frontier of the unfolding universe. Similarly, an intuition of moral, aesthetic, or epistemological transcendence is simply the experience of having particular kinds of experiences in those categories.
Transcendence on this view, would be an authentic experience and no delusion. But an experience of what precisely? Is it simply a sufficient conviction of adequacy for some purpose? A moral feeling indicates certainty of our probable interests as affected by our own behaviour and that of others; our aesthetic judgment a certainty that, at least provisionally, we approve this sensation; and our epistemological sensation tells us that we know just enough to act or, as importantly, not to act.
In all cases, it seems that our self-interest is engaged; which is no surprise in general, but will not be what some expect in this instance. Far from being selfless, the intuition of transcendence seems to have its roots in the clearly perceived interest of the organism.