Do you have a metric or process , which could scientifically tell if person is a Christian or not ? I don ' t think we can accurately judge whether or not a person is Christian , except ourselves . I would refer to Romans 109 as my metric . Unless mind reading is possible , the second part of that metric is cannot be confirmed . And what if person calls themselves a Christian , yet your metric does not confirm this ? The , according to my metric , they are not . If no , then what is point of calling yourself a Christian ? Just like identifying myself with nationality , or the lack of , gender , orientation , race , marital status , etc . What is point of trying to show us that Christianity is worth the time and resources it uses ? Wouldn ' t it be better to use that time and resources to solve actual scientificallybacked problems like global warming ? It is like hey , I just got myself a new favourite book I think it is super awesome ! You should read it too !