Timaeus was written around 360BC and it's part of the old-age or dialectical dialogues of Plato. - This work had a great influence on later philosophy and science , and was also the first written source of the Atlantis myth . - Three problems are essentially explored in depth: the cosmological one about the origin of the cosmos, the physical one about its structure, and finally the one regarding the Hyperuranic nature . - The participants in the dialogue are Socrates , the pythagoric astronomer Timaeus of Locri, Critias and Hermocrates. - In the prologue Socrates wants to have a concrete demonstration of the ideal city theorized the day before; so Critias at this point recounts the ancient Atlantis created by Poseidon and later destroyed by the same after having tempted to conquer Athens for the greed and yearning of his inhabitants. - In the first part it's only Timaeus the speaker, Plato here to reconcile the dualism between the intelligible world and the sensitive world uses his voice to introduce a myth that has as a protagonist the figure of the Demiurge . - The universe is then populated with asters whose rotation reproduces the perfection of the world of ideas and after them by living beings within which are infused immaterial souls that bind them to the world of ideas within material bodies . - In the second part, the astronomer treats the structure of the universe , which is spherical and contains four elements , associated with as many geometric shapes , that combine in various ways to create the variety of existing things: Air (Octahedron); Water (Icosahedron); Earth (Hexahedron); Fire (Tetrahedron). - In the final part of the dialogue are described, the physical characteristics of human beings, analyzing the functions and constitution of the various organs and mortal parts.