Tusko writes:
But perhaps there is something to be said for the relationship between the rational and the visionary.
This sounds a bit like the thin line between genius and madness idea.
It may be that we just notice a touch of madness more if it comes from someone considered highly intelligent.
I'm not really applying the following to Newton, very much a man of his times, or Conan Doyle, who perhaps had a strong desire for things like the existence of fairies that made him vulnerable to a hoax, but who didn't actually see the fairies himself.
There's no reason why good scientists shouldn't suffer from neurological conditions, just like the rest of us. Anyone can develop a condition that could lead them to seeing luminous talking raccoons in the woods, and such people can still be capable of impressive achievements in practical life.
So, a mild touch of schizophrenia or epilepsy is my explanation for the "weird book" in Percy's O.P.
If we consider that we may all have slight glitches in the brain (I had a few very odd
deja vu experiences when I was a kid) then it's just a matter of degree, perhaps, when someone gets to the point where we could definitely define an illness.
Some people seem more likely to see ghosts than others. Having "extra-sensory perception", and having a very mild neurological condition may be one and the same things.
I think it's about 1% of the population that suffers from schizophrenia. So, if 1% of scientists have the condition, we can expect the occasional weird book to appear!