Full Idea
The soul and body fall asleep together. The soul slowly becomes paralysed, together with all the body's muscles. They can no longer hold up the weight of the head, while the soul can no longer bear the burden of thought.
Gist of Idea
When falling asleep, the soul becomes paralysed and weak, just like the body
Source
Julien Offray de La Mettrie (Machine Man [1747], p.6)
Book Reference
La Mettrie,Julien Offray de: 'Machine Man and Other Writings', ed/tr. Thomson,Ann [CUP 1996], p.6
A Reaction
A very nice observation, to place alongside other evidence such as drunkenness and blushing. Personally I find it hard to see why anyone ever believed dualism. You don't need modern brain scans and brain lesion research to see the problem.