[HowardtheDuck]

If we repeat what is in the recorded teachings than how do we know that we have actually achieved a realisation?

if "realisation" is not the same as the recorded teachings, how can it be trusted to be genuine realisation?

Zen asks for something different from the "recorded teachings".

if that is the case, is it a different dharma (or doctrine)? is it really "Buddhism"?

please keep in mind the historical Buddha rejected the spheres of nothingness, infinite consciousnes, non-perception, etc, as Nirvana

And if you apply the concept of impermanence to the recorded and established teachings?

where is Zen the most established? in the USA? if so, what explains its decline & impermanence?

This could be "learnt" without a realisation.

it could be. If so, what is wrong with this?

Hmmm ... Zen is notoriously silent on many things ... including Awakening ...

is this an appeal to authority & dogma? can esoteric philosophy also become a dogma, attached to?

is attachment to silence, attachment? is attachment to non-becoming, attachment? is resistence to conventional truth, attachment?