„Although all the types of rays emanate simultaneously from the sun, the colors that light is composed of would remain hidden from us, and all bodies would appear to be the same color as sunlight, if those bodies did not act upon the rays. Thus, the action of bodies [254v] on light is necessary for light to reveal its colors. But this action is limited by the very nature of the rays, and the bodies do not change their nature—rather, they simply give them the opportunity to reveal it.“ (Translation of L’action des corps sur la lumière est nécessaire pour faire paraître les couleurs ~ Du Châtelet)
Would you like to read more? Then take a look at Émilie Du Châtelet’s Essai sur l’Optique here:
„Although all the types of rays emanate simultaneously from the sun, the colors that light is composed of would remain hidden from us, and all bodies would appear to be the same color as sunlight, if those bodies did not act upon the rays. Thus, the action of bodies [254v] on light is necessary for light to reveal its colors. But this action is limited by the very nature of the rays, and the bodies do not change their nature—rather, they simply give them the opportunity to reveal it.“ (Translation of L’action des corps sur la lumière est nécessaire pour faire paraître les couleurs ~ Du Châtelet)