Anaxagoras (active at Athens in the mid 5th c.), was evidently an influential associate of Pericles, the architect of  Athens' Golden Age.

Anaxagoras was a rationalist who explained the universe in largely mechanistic terms, accessible to human intelligence.

The materials of this world are made up of infinitesimal 'seeds,' each containing a trace of all qualities. Genesis (change) is a process driven by the Vortex or Whirl, directed by Mind. (Simplicius Phys. 164.24 & 156.13)

All other things have a portion of everything, but Mind (Nous) is infinite and self-governed, unmixed, integral and apart unto itself. ...

For [Mind] is the finest of all things and the purest, it has all knowledge about everything and the greatest power; and Mind controls all things, both great and small, that have life. Mind controlled the rotation [of the world], causing the rotation in the beginning. The whirl began from a small area but has spun outward to involve an ever widening area. [This spinning process causes the mixing and separating of materials] And the things that are mixed and separated and divided off, all are known by Mind ...

all that were to be, all things that once were but are no longer, and all that remain, Mind arranged, including the rotation of the stars, the sun and moon, the air and the aither that are separated [into their spheres].

The rotation/spin caused this separation: the dense is parted from the thin, the hot from the cold, the bright from the dark, and the dry from the moist.

Early atomists, Leucippus and Democritus, supposed that the qualities of material things are a product of the shapes of atoms, and this variation of shapes and sizes may be (almost) infinite. The constant mixture of atoms is here (as with Anaxagoras) caused by the vast whirl/spin (Dine) of the universe. It is clear that the atomists regarded this force as mechanical, but the notion was still so novel that the comedians ridiculed it by calling Dine a false god.