To which must be remarked that neurology may assume as a valid theory that the outer world produces the same changes in my brain and in another man’s; but that, strictly keeping to my experience, I have never observed it and never can observe it. ###>La neurologie peut accepter cette idée comme une théorie valable, mais si je m'en tiens à mon expérience, je n'en ai jamais eu la preuve visuelle et je ne l'aurai jamais.