One of my fantasy dinner party guests, heroes, and top choices if I were ranking historical figures based on how much they fascinate me in the present, R.D. Laing was the pioneer of the 60's anti-psychiatry movement. His belief that insanity as observed from the outside as what one would call insanity is only a sane reaction to an insane environment as it is experienced by the one who is supposedly insane was one that stood in direct opposition to attitudes of contemporary Western medicine, which advocated medication and electroshock convulsion treatment and lobotomies and other such extreme physiologically-damaging procedures. Most importantly, he taught that we can never truly experience the world as anyone but we ourselves are experiencing it. We can only observe, and experience the observing of those who are observing our experience of observing them etc. etc. So we can never wholly understand what is mad and what is not because we are all experiencing it all so differently, and putting us into diagnostic categories can be dangerous when it starts to cut divides between peoples and marginalise some and put people into boxes where they will not be treated as human, for labels of 'madness' remove all credibility, a basic human right.
I made a little film about him. Mostly it's about the audio and what he says but the clips are there to aid the listening.