 The third main section of the discourse—about the cooperation of Intellect with Necessity—focuses primarily on the psychophysical construction of the human being. While the Craftsman has created the individual souls, he delegates the creation of the human bodies to the lesser, created gods. As individual immortal (and rational) souls are embodied in mortal bodies, the embodiment requires the further creation of the “mortal” parts of the soul—the spirited and appetitive parts, familiar from the Republic and the Phaedrus. These parts are assigned their respective locations in the body: the immortal and rational soul in the head, and the two parts of the mortal soul in the trunk: the spirited part in the chest (nearer to the head) and the appetitive part in the belly. The various organs in the trunk—the lungs and heart in the chest and the liver in the belly—support the functions of their resident soul parts. The account proceeds to describe the formation of the various bodily parts, setting out in each case the purpose of the part in question and showing how its construction (out of the appropriately selected materials) serves that purpose. The purpose is prescribed by Intellect, and the properties of the materials—selected because their properties render them compliant to Intellect’s purposes—are the consequences (and thus contributions) of Necessity. For the most part, Necessity serves the purposes of Intellect well, but this is not always the case. A notable example of them coming apart is the covering around the brain. That covering needs to be massive to provide maximal protection, but that very massiveness would impede sensation, and so a preferential choice must be made between the conflicting demands. Such occasional cases of resistance by Necessity to the “persuasion” of Intellect limit the degree of excellence the created world can attain. Timaeus’ discourse moves on with an account of the mechanisms of respiration and digestion, and a classification and etiological discussion of various diseases of both body and soul. This is preparatory to an exhortation to properly exercise both the soul and the body to recover or maintain physical and psychic well being. The well being of the soul in particular is emphasized: it is through realigning the motions of our souls with those of the universe at large that we achieve our goal of living virtuously and happily. The discourse concludes with an account of the generation of women and non-human animals.