I think it's the idea that spiritual things can be known without any valid argument or objective evidence. It's what Huxley was setting himself against when he coined the term 'agnostic' to mean:
"...That it is wrong for a man to say he is certain of the objective truth of a proposition unless he can provide evidence which logically justifies that certainty."
The concept of Gnosticism is O.K. for those who believe "less" in God and more on the here and now with you in control therefore nothing is perfect. Christians on the other hand believe that God is perfect and we should strive every waking moment to reach that Nirvana.
I think the link below should be explored, contemplated and mindfully entertained.