The Opus Majus of Roger Bacon

Properties apprehended by sense.

particular sense do not judge by themselves except concerning twenty-nine sensibles; such as sight concerning light and color; touch concerning heat and cold, moisture and dryness; hearing concerning sound; smell concerning odor; taste concerning flavor. And these are the nine proper sensibles, which are appropriated to their own senses, as I have named; concerning which no other particular sense can judge. There are, however, twenty original: "viginti" — note: the manuscript notes 22 in Alhazen, but Bacon counts 29 total in his specific classification system. other sensibles, namely: remoteness, position, corporeity, figure, magnitude, continuation, discretion or separation, number, motion, rest, roughness, smoothness, diaphaneity, thickness, shadow, obscurity, beauty, ugliness; likewise, similarity and diversity in all of these, and in all things composed of these. And besides these, there are some that are placed under one or more of these, such as ordering under position, and writing and painting under figure and ordering; and as straightness and curvature, and concavity and convexity, which are placed under figure; and multitude and paucity, which are placed under number; and as equality, and growth, and diminution, which are placed under similarity and diversity; and as cheerfulness and laughter and sadness, which are understood from the figure and shape of the face; and as weeping, which is understood from the figure of the face along with the motion of tears; and as moisture and dryness, which are placed under motion and rest, since moisture is not comprehended by the sense of sight, except from the liquidity of the moist body and from the motion of one part of it before another, and dryness is comprehended from the retention of the parts of the dry thing and from the privation of liquidity. Here, however, it must be considered that Aristotle intends, in the second book De Generatione On Generation, that the moist and the dry are in one way primary qualities, which are naturally due to the elements, and through them arise elemental moisture and dryness, which are reduced to the primary ones and are caused by them. Therefore, it has been said concerning the primary ones that they are proper sensibles, and perceptible by touch alone. Mention is made here of the others. For the first moisture is that which easily passes into all figures that are poorly terminable by themselves, but well by an alien boundary, as in air most especially, and then in water. Dryness...