Out of curiosity, I always wondered what exactly would define 'proof' in this circumstance.

Dictionary:
Proof: any factual evidence that helps to establish the truth of something;

Wont the word 'proof' or what things some may establish as 'proof' be observed from many perspectives by many individuals? Is something defined as fact when the majority of such individuals agree on something? ie someone may write up what they consider a logical evidential response that God does or does not exist, yet the perspective of others may not agree with such logic because we all think differently and see things differently. Unless there is some universal way of understanding the words 'proof' and 'evidence' that all could agree on and come to an understanding on...I guess that is very unlikely to happen because I assume alot of the conflict in this world is caused from individuals seeing things differently...