 This intention explains certain peculiarities of the Timaeus that make the dialogue hard to penetrate. For the dialogue falls into three rather disparate parts. The first part describes the structure of the world-soul and its replication in the human soul in a way that combines the formal principles with those of mathematics and harmonics and illustrates it with fantastic imagery (29d–47e). The second part consists of a rather meticulous account of the elementary physical constituents of nature, which are held to be formed of geometrically constructed atoms (47e–69a). The third part combines elements from the first and second parts in a lengthy explanation of human physiology and psychology (69b–92c). The first, cosmological, part of the Timaeus greatly taxes one’s ability to relate the notion of a divinely created world-soul to the motions of the visible heavens, since Plato only offers the bare hints of an intelligible, mathematical, and harmonic structure that would explain these motions. By contrast, the explanations in the second and third part are hard to follow because of Plato’s, quite unique, concern with detail with respect to nature.