3) societal: insanity in isolation does not hurt, and some people with interesting outlandish worldview still live happily without being labelled as "insane". Ultimately, if an "insane" individual start to affect others, the society will need to determine whether we should label him as insane and get her some treatment. read more
For that we will have to define sanity first. The difference between the two is a thin zigzag line and we really just use ‘socially acceptable behavior’ as the major criteria to differentiate. Furthermore if insanity is defined by sane people, then sanity will have to be defined by insane people. read more