Leucippus and his students Democritus were the forefathers of today’s theory of atoms. However, in that era, their theory was not as widely accepted as the theory of Empedocles – the four elements. The duo asserted that every material in the universe can be reduced to its one minute-building block which they called atomos – meaning uncuttable. They continued to develop their thesis by suggesting that atomos – or how we know them today – atoms can freely move through the emptiness and combine to form changing configurations. Additionally, they reasoned that atoms are infinite in amount, of different types, and indestructible. This means that they will always exist, and can fuse together to form all sorts of substances, and when these substances decay the atoms do not disappear but merely change forms and continue the cycle of reconstruction.
Perhaps, the reason why this theory was not accepted by philosophers of the 5th century BCE was the underlying idea of the existence of emptiness or void that they found unacceptable at that time.
