With regards to mental ability, Genius and Madness are considered to be extremes in description, but are principally labels of appreciation/understanding and recognition - in credibility. If anyone, within a small group, exclaimed that the world (without scientific evidence or corroboration supporting the theory) and every part of our universe were the result of a 'big bang' and insisted this was true, the probability is that this person would be at least treated as ridiculous if this idea went against the prevailing explanation. Arguments against the supposition are likely to include sceptical dismissal or, potentially, accusation in a form of madness by association.
Whereas, with a background appreciation of empirical scientific evidence and method, any scientific theory can (and frequently is) accepted upon proposal within the boundaries of credibility they stand on. So in effect, it's a matter of repute that finds more acceptance and by definition claims and is awarded credibility - what's considered in general terms as such.
Conversely, within the boundaries of madness, anything can be stated and be as true or evidently not without distinction in real terms or appreciation. What makes one description more applicable than an other is, I suspect, largely based on what's generally considered normal (though in modern terms - more often than not - the consensus of opinion is that 'normal' defies definition).
In other words, science is bordering on, without Actually accusing the masses of some form of insanity within 'delusional' frame terms - as the majority of the civilised (and uncivilised) world have some belief system that goes against the acknowledged scientific explanation of the world - GOD and/or any spiritual beliefs.
Science can't find evidence of a God and so the current premise is that ... scientifically, there is no God or any of the known associations.
Delusional?
Who is?
Who gains from that belief? - Who doesn't and Who decides?
