[HakTaisanip]

I have been looking (very lightly) at the Anatta concept.While I see it as an ultra obscure philosophical notion; this again, within my very limited knowledge in this area, I would like to ask two questions.
(1) Is impermanency seen to persist relevant to our finite (illusionary grasp) in terms of what we percieve...e.g animals, trees, humans etc. Does this cognative stuff become eventually extinct, or is their a perpetual backwards/ forwards flux.
Permanent change would seem to indicate ever changing phenomena and extinction of some former things.
(2) Is Anatta a contentious issue within Buddhist circles. Thank you.