I do know what Gnosis means, the Buddhists mean the same by Enlightenment. Inherently, it means that a person has realised that any and all meaning, justice, purpose etc come from within the self. The problem lies in the idea that this is somehow linked to a universal meaning or purpose -a spiritual journey which everyone should or must take.
Intuition, as a concept, covers a mutitude of sins. It can be an innate ability to read peoples' body language and micro-expressions. It can be a signal that the person possessing it is a Psyker of some kind. Or it can simply be coming across an idea or concept with which you are psychologically comfortable.
The point about the falling tree is that we do not experience reality, but only the signs of the signs that our senses can pick up. These signs are filtered by our experiences, culture etc and thus nobody sees, hears or feels exactly what everyone else does.
We have the ability to make choices our ancestors could not because of our technology and developed societies. Early humans ate what they could get or starved, they couldn't afford moral scruples.
Nietzsche was definitely unbalanced, but like many philosophers and mystics both before and after him, he was seeking toward Transhuman status. Like so many other human dreams -flight, for instance - our technology is offering us a way to achieve that status.
I write - I create whole worlds on paper. I do not lack imagination, I merely recognise it for what it is.
Drugs, meditation, yoga - all out of date. If we wish to transcend our current mortal and earthbound status, we need to to it they way we've done everything else, with technology.