LEUCIPPUSAbdera, 5th century B.C.
A Greek philosopher of the second half of the 5th century BC, who assumed as the doctor-philosopher Galenus informs us the existence of atoms, inserting and creating this philosophical theory, which was evolved and perfected by his pupil Democritus, and later on from Epicurus, the Stoics and Lucretius. He was born in Miletus, and was a student of Xenon the Eleat.
Leukippus didn't connect necessity to movement. As Plato, he believed in the existence of a stable and unaltered energy of action and reaction, genesis and decay, out of which the movement of atoms and their combinations (shapes).
He believed that constant organized movement is a natural and primary characteristic of things, that explains the action inside them. He though movement as one way of existence of the "Vacuum"
Atoms and vacuum coexist within everything, with infinite combinations, based on spinning, connecting, composing and decomposing, complication and conflict, all managed by symmetry and balance.