Did you know Newton was born on Christmas Day ? ( the old calendar, of course. )
Right at the end of the Principia Mathematica, in the General Scholium, he gives his famous affirmation of the Lord God as Universal Ruler, brusquely concluding, "... and thus much concerning God, to discourse of whom from the appearances of things, does certainly belong to Natural Philosophy."
Then, in the very last paragraph, he begins, "And now we might add something concerning a cerain most subtle spirit which pervades and lies hid in all gross bodies." Speculating that, "... animal bodies move at the command of the will, namely by the vibrations of this spirit, mutually propagated along the solid filaments of the nerves, from the outward organs of sense to the brain, and from the brain to the muscles."
As a matter of fact, he felt compelled to add his affirmation of God in a later edition because critics thought the Principia promoted atheism, particularly, as I recall, by his remark that "Absolute true and mathematical time, of itself, and from its own nature, flows without reference to anything external, ...", but note he did not see the necessity of amending this declaration.
Anyway, I've always thought his headlong plunge at the very end into a materialistic speculation on the nature of perception and motor control was quite striking.
“Then, in the very last paragraph, he begins, “And now we might add something concerning a cerain most subtle spirit which pervades and lies hid in all gross bodies.” Speculating that, “... animal bodies move at the command of the will, namely by the vibrations of this spirit, mutually propagated along the solid filaments of the nerves, from the outward organs of sense to the brain, and from the brain to the muscles.”
Well, that’s more-or-less expressing a belief in pantheism (ie. that the universe itself is God). This sort of thinking is common among men of science. Einstein was a pantheist, as was Carl Sagan, and also Stephen Hawking.
Newton considered himself a Unitarian (a Christian who does not believe in the Holy Trinity or the divinity of Jesus) and wrote extensively on religion and the occult.