If I may respectfully refer to the (failed) experiment in An unique experiment - First time on a buddhist forum
Whoever thinks they can ‘refute’ atman, please consider if they could have gone to Ramana and refute his atman so that in the end he would have given up and admitted defeat? I don’t think so.
I’m not saying that there is (or is not) an atman (in whatever historical meaning). It’s just a pointless debate. Anicca is the key to the ‘buddhist anatta’, and obviously Ramana and others locate ‘their’ atman beyond anicca.
Just replace their ‘atman’ with ‘the deathless’ - a perfectly fine buddhist synonym for nibbana - and most of the problem has disappeared.