Arthur Koestler is an interesting and ambiguous figure. Communist, Zionist, paranormalist. Described as childish in his constant enthusiasms that ranged from science to psychoanalysis. In his paranormal and nationalist ways, quite sympathetic to the right. Completely bonkers.
Artists never stop looking at things in new ways. They never stop growing. This makes them unstable, of course. A bit like perpetual teenagers, except arguably they practice a high kind of maturity. You saw this with David Bowie, and his different stages (contact with archetypes)