Born in Abdera, in ancient Thrace, Democritus lived from 460BC to 370BC and died at 90 years of age.  Democritus  opened the doors to the natural sciences by basing his explanations of phenomena in natural terms and not supernatural ones.  It has been said the first phase of Greek Philosophy ended with Democritus.

Scope of studyEdit

Democritus wrote on various topics that encompass most the areas of ancient study – mathematics, physics, medicine, agriculture, ethics, poetry, grammar, music, painting, aesthetics, and acoustics. Unfortunately many of the documents are lost, with the exception of only a few.

Atomic TheoryEdit

Democritus was the first to conceive of atomic theory. Sometheories indicate that he may have learned the basics of this theory from his teacher, the Materialist Philosopher Leucippus, from the 5th century BC. Democritus wanted to broaden atomic theory to include explanations for all physical phenomena. He further developed Leucippus’ atomic theory, which today’s scientists have placed as a base of modern theory. Democritus identified natural laws that govern sound, light, and heat as well as large scale chemical reactions, with his conclusion reaching the conception of the splitting of the atom.

Democritus considered two basic elements, the "Πληρες" (the full) and the "Κενο" (the empty or the void). The "Πληρες" is comprised of tiny particles that can no longer be subdivided, which he calls atoms. Democritus's atoms were conceived of being of different shapes, and different sizes, but were beneath the level of our senses and can only be conceived of intuitively. Atoms are likewise eternal, as is their movement. Atomic movement is described as rotating within the "Κενο", like “dust in the wind”. As these particles collide they coalesce into larger bodies and form countless worlds "Τον μεγα διακοσμο", and in one of these worlds, exists the earth.

Democritus believed that there exists nothing else real, nothing definitive, except the original atoms, and the void.


After traveling to various major ancient lands (e.g. Egypt, Syria and Persia), Democritus settled back in Thrace to research and teach in the school that he founded in 420BC. In this school he developed his own system of philosophy. Democritus spent a great deal of time in Athens where he witnessed Socrates debating with others but did not approach him. 


Like Diogenes, he was not very socially ambitious. “I came to Athens and nobody acknowledged me as a philosopher”, he said. But quite to the contrary, his new cosmological theories made a great impact on his contemporaries, so far as for them to call him a “Pentathlete”. One thing that defined Democritus was his ability to laugh at the problems others considered overwhelming when comparing these problems to the magnitude of the universe. That’s why he was dubbed, "Γελασινός" (one who laughs).

Ontological TheoryEdit

Democritus has held that the "Ον" (being/matter itself) is eternal and indestructible. Unlike the Eleatics, he believe that the "Ον" was not of one nature, but of many. he "Ον" is no more real than the Non-"Ον", because the void is no less real than matter. The universe is a combination of all the interactions between the atoms – which change in three directions, morphology, content and position.


In his work "On Happiness", Democritus offered his opinions on governance, the polity, and on social ethics. In, "The Ethics" he examines many of the ethical problems that are analyzed by his contemporary, Socrates. Based on his work, Democritus demonstrated that not only was he a great thinker, but also a person who involved himself with social problems and developed solutions to solve these problems.


  • “For a single definitive scientific explanation I’ll give the entire Persian kingdom”, he was quoted as saying – an expression of his love for science.
  • “In reality we know nothing, for truth is buried in the abyss”.
  • "The world is but a stage, and life is a passing thing, we come - we see - we leave."