a few minutes' reflection, Louis said to me:

"If the landscape did not come to me--which it is absurd to imagine--I
must have come here. If I was here while I was asleep in my cubicle,
does not that constitute a complete severance of my body and my inner
being? Does it not prove some inscrutable locomotive faculty in the
spirit with effects resembling those of locomotion in the body? Well,
then, if my spirit and my body can be severed during sleep, why should
I not insist on their separating in the same way while I am awake? I
see no half-way mean between the two propositions.

"But if we go further into details: either the facts are due to the
action of a faculty which brings out a second being to whom my body is
merely a husk, since I was in my cell, and yet I saw the landscape
--and this upsets many systems; or the facts took place either in some
nerve centre, of which the name is yet to be discovered, where our
feelings dwell and move; or else in the cerebral centre, where ideas
are formed. This last hypothesis gives rise to some strange questions.
I walked, I saw, I heard. Motion is inconceivable but in space, sound
acts only at certain angles or on surfaces, color is caused only by
light. If, in the dark, with my eyes shut, I saw, in myself, colored
objects; if I heard sounds in the most perfect silence and without the
conditions requisite for the production of sound; if without stirring
I traversed wide tracts of space, there must be inner faculties
independent of the external laws of physics. Material nature must be
penetrable by the spirit.

"How is it that men have hitherto given so little thought to the
phenomena of sleep, which seem to prove that man has a double life?
May there not be a new science lying beneath them?" he added, striking