Abstract: Discusses the structure and content of Le Monde, which deals with corpuscularianism, a theory of matter based on fluid mechanics containing the contentious theories of conservation of motion and the non-existence of vacua. The work also presents a definition of the nature of colour, uses a hypothetical ‘new world’ (which when compared with the real world will be found to be indistinguishable from it) to define his cosmology, and sets out a theory of light that explains the behaviour of light rays with particular reference to rainbows. By analogy with Le Monde, L’Homme presents the mechanistic physiology of imaginary beings. Discusses psycho-physiological functions, by means of reference to the actions of automata, and the implications these have for the difference between human and animal cognition, and whether animals have souls.

Keywords: automata, cognition, conservation of motion, corpuscularianism, cosmology, L’Homme, Le Monde, nature of colour, optics, physics, physiology, theory of light,