are composites of some basic elements; although it is not clear what these elements are. All objects are a mixture of these building blocks and have a portion of each element, except nous. Nous was also considered a building block of the cosmos, but it exists only in living objects. Anaxagoras writes: "In everything there is a portion (moira) of everything except mind (nous), but there are some things in which mind too is present." Nous was not just an element of things, somehow it was the cause of setting the universe into motion. Anaxagoras advanced Milesian thought on epistemology, striving to establish an explanation that could be valid for all natural phenomena. Influenced by the Eleatics, he also furthered the exploration of metatheoretical questions such as the nature of knowledge. Empedocles was born in Akragas, a town in the southern Italian peninsula. According to Diogenes Laertius, Empedocles wrote two books in the form of poems: Peri Physeos (On nature) and the Katharmoi (Purifications). Some contemporary scholars argue these books might be one; all agree that interpreting Empedocles is difficult. On cosmological issues, Empedocles takes from the Eleatic school the idea that the universe is unborn, has always been and always will be. He also continues Anaxagoras' thought on the four "roots" (i.e., classical elements), that by intermixing, they create all things around us. These roots are fire, air, earth, and water. Crucially, he adds two more components, the immaterial forces of love and strife. These two forces are opposite and by acting upon the material of the four roots unite in harmony or tear apart the four roots, with the resulting mixture being all things that exist. Empedocles uses an analogy of how this is possible: as a painter uses a few basic colors to create a painting, the same happens with the four roots. It is not quite clear if love and strife co-operate or have a greater plan, but love and strife are in a continual cycle that generates life and the earth we live in. Other beings, apart from the four roots and love and strife, according to Empedocles' Purifications are mortals, gods, and daemons. Like Pythagoras, Empedocles believed in the soul's transmigration and was vegetarian. Atomists: Leucippus and Democritus Leucippus and Democritus both lived in Abdera, in Thrace. They are most famous for their atomic cosmology even though their thought included many other fields of