If it was in the late '60s and he got into parapsychology and wondering if the sun is conscious, that's a very big hint of what "happened" to him. That generation is probably still pissing off all the drugs it took to roll back that high and beautiful wave [1].
This is not just a glib comment btw. I have some history with that kind of thing. When I was just small I discovered my mother's library, that happened to be full of New Age books that were popular with her and her friends as she was growing up, I guess: yoga, reiki, orientalism, astrology, Arthur Koestler, Wilhelm Reich, Aldus Huxley and Carlos Castaneda... I am a voracious reader, and I read them voraciously. I had the luxury of reading them in an age that was too young for the psychedelic drugs praised by some of them (Huxley and Castaneda, mainly, who were also the best writers of the bunch) and so managed to read them critically, I guess, and recognise their deep flaws [2]. I can imagine how hard it would have been to think critically if I had read those books under the influence of the kind of drugs people took in the '60s.
And later. Growing up I had a friend who would regularly smoke hash and sit down and read the bible. He was at least half mad. A dear friend, but half mad. Drugs aren't good for criticial thinking.
I think our man, Sheldrake, he fried his brain on drugs and that's how he can now think that the sun might be conscious, and that people can tell when someone's staring at them. I have another friend who smokes a lot of hash and is at least half mad and he's a big fan of Sheldrake. This friend is convinced that people can hear his thoughts. I think he believes he's telepathic and he is inadvertently projecting his thoughts into peoples' heads.
Sometimes I think of all the people I know who go about their lives with their heads full of beliefs that never need touch reality, and it weirds me out a bit. Think of how many people believe in gods, or in aliens, or in reincarnation. I cross paths with those people everyday, we occupy the same physical space, but they live in a different world that I can't see or feel. That a guy trained in biochemistry (and who probably was a bit too friendly with chemistry for his own good) has made a whole world model out of nothing more than his imagination is not a big surprise.
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[1] https://www.goodreads.com/quotes/1074-strange-memories-on-th...
[2] Take astrology, for instance. My mother had a 13-tome opus, with one tome on each sign, plus one for the general stuff. I read my own sign's tome first and I was inspired: everything in there described me so perfectly! Then I read the tome for another sign; and that, too, described me perfectly. So did the next, and the next. Soon I realised that the "perfect descriptions" of my personality were doing nothing more than flattering me, for having aspects to my personality that basically everyone has. They were just trying to get me hooked by telling me how cool I really am, because I'm an X sign.