The big discovery that came out when they re-examined all the reams of writing he left is that the greater part of it was religious writings. And not about ethics, but about things like Bible codes, obscure messages he saw woven into the text. Also, in Opticks there is included a long passage of completely crazy stream of consciousness about light. He dropped all pretense of rigor and let loose with a new age sounding jumble of exited dreaming about light.
Learning these things, and let's not forget his extensive work in alchemy, I get a sense of Newton as a thorough lunatic who, unlike most lunatics, discovered he could hold himself together when needed by a strict adherence to rigor and logic.