This man was simply genious and this is already something to be simple and a genious in the same time. He came through using the mental capacity fully to the borders of it and at this point came accros that what goes beyond matter, the spiritual. He had some phantastic insights, so in his old days he became intrested in the world of the mysterious...
That's the greatness in science, if scientists really go totally deep into it they come to the borders of this world and there it crosses the spiritual world...