By definition, insanity is unreasonableness, or the inability to think in orderly and rational ways. Therefore, insanity is rooted in a person's unconventional thinking.
But conventions change, especially those customs of thought. Our processes are constantly evolving to incorporate new, previously unthinkable concepts, such as human flight, space exploration, even a 40-hour work week.
Perhaps the "insane" have more to offer than we in safe sanity would like to believe. Perhaps they are seeing a reality as yet unrevealed to us.