The Proof of the Pudding
For a start let us remind ourselves, that the materialist tenet of - awareness having somehow spontaneously arisen from the brain - is just a belief and has been in no way proven or verified.
In contrast there is ample evidence - inner and outer - , that awareness - the core of our being - the 'amness' that perceives, feels, thinks, believes ... - is an entity, which is independent of our body.
If you have an open mind - not fixed on any belief system - you can sit down in a quiet space and ask yourself the core question of all sages: 'Who really am I, who really is this 'I' in me. You turn your perception on itself and gently ask: 'Is there a beginning to myself - spatially or temporally' and 'listen' for the answer that arises spontaneously inside. We are not talking of your body, belief system, feelings, thoughts and all the other stuff we usually identify with, but which are indeed very limited and spatially and temporally. Just your core.
The answer, which everyone down the ages has received to this quest(ion) is a fine but resounding 'NO'. Shazam - you have discovered the Eternal + Divine Fractal which is your and everyones Core. Ancient Indian Vedas, the Oracle of Delphi ("Know thyself and you will know God" and all Mystics have received only that one answer.
If that does not work for you, but you are still open to the possibility, there is multiple external evidence. Main sources are:
