Galien et le visible dans le De elementis : l’usage des couleurs dans la connaissance du vivant

Galen often uses, in various treatises and especially in his De elementis, examples based on colours. Reasons of rhetorical efficacy can probably account for this choice, as well as the will to rekindle earlier philosophical traditions. But for him, the problem also lies in the production of evidence. The colours quoted, usually in a very limited number, also correspond to the four humours which constitute the human body. We can see the colours of the human body only because it excretes, volontarily or not, the humours which make it up.