Now, as it was plain to my father, that all souls were by nature equal, ----and that the great difference between the most acute and the most obtuse understanding----was from no original sharpness or bluntness of one thinking substance above or below another, ----but arose merely from the lucky or unlucky organisation of the body, in that part where the soul principally took up her residence, ----he had made it the subject of his enquiry to find out the identical place.

Now, it was plain to my father that all souls were equal, and that the difference between the most acute and the most obtuse understanding came not from any original sharpness or bluntness of one mind above or below another, but arose merely from the organisation of the body, in that part where the soul took up her residence. He had therefore researched exactly where that was.
