 According to (i), the first among the (arts and) sciences are the mechanical arts because they result from the necessity to assist human beings in surpassing their natural physical constraints (DOS 358). Human beings are, in comparison with other animals, weaker in body, and therefore tend to devise forms to surpass this deficiency (DOS 626); but they are gifted (by God) with reason to discover ways to surpass their physical limitations (DOS 360–61). The sub-divisions of the mechanical arts obey the principles laid out in Hugh of St. Victor’s Didascalicon—as Kilwardby himself makes explicit (see DOS, chapters 37–39). Special attention must be paid to the similarity between the scheme of the seven liberal arts and the seven mechanical arts that Hugh defends and Robert follows (DOS 363): as the liberal arts divide into trivium (sciences of language) and quadrivium (sciences of things) the mechanical arts also divide into a group of three arts concerning those things related to what is external to the body (extrinsecus corporis)—clothing, weaponry (further divided into architecture and industry), and navigation—and a group of four arts focusing on what is internal to the body (intrinsecus corporis)—agriculture, hunting, medicine, and theatre.