I believe that the least remarkable of Democritus' very great contributions was his "atomic theory", which was basically accepted by modern science 2000 years later (with some refinement and modification). His atomic theory was naturally highly suggestive of some quantum phenomena also. The most remarkable thing about Democritus' Atomic Theory was that he devised it by violating every major principle of modern science, especially the importance of empirical observations and "reasonable" testability. (Could he have developed it any other way? …
