Transcendence is not a human possibility because humanity is itself a transcendental possibility of consciousness.
We are not human beings with consciousness. We are only experienced to be human beings with consciousness.
It is not humans who are conscious. It is consciousness that experiences itself as humanity.
Only consciousness can know and say that it is consciousness.
Nothing can exist but consciousness.
If natural phenomena could exist apart from consciousness, and if consciousness is a natural phenomenon, then consciousness could exist apart from consciousness, that is, there could exist consciousness without there existing a consciousness at all; or, consciousness could exist without being conscious of itself as consciousness. This again amounts to saying that there could exist conscious experience without it being someone’s experience: Consciousness could exist without there existing a conscious agent!
Absurd.