15. How Are the Eternal Forces of the Human Soul Investigated?

This same de La Mettrie says, for example: Man's mental qualities, everything he reveals of his soul to the outside world, are so dependent on the mechanism of his body that one can say: If only some little thing in the brain of Erasmus or of Fontenelle – a little thing that cannot even be proved anatomically – had been different, then Erasmus and Fontenelle might have become blockheads instead of geniuses!