Democritus was a man of vision who, in the 5th Century BC, developed an atomic theory that anticipated modern principles of matter and energy, who recognised the Milky Way as light from other stars, and who didn't believe in the gods but thought man was responsible for his own future. The origin of his nickname, the 'Laughing Philosopher', is subject to debate. Some sources suggest that it derives from his theory that man's highest ethical goal is 'cheerfulness'. A less flattering explanation, expressed by the Roman philosopher Seneca (4BC - 65AD), is that Democritus was prone to displaying his contempt of human absurdity by laughing at his fellow-citizens, who in turn, called him 'the mocker'.

Perhaps because he had problems with his people skills, or more likely because he held beliefs that were unpopular with many of his more influential contemporaries such as Plato (427 - 347 BC), Democritus remained a relatively obscure Greek philosopher for many centuries, achieving a minor renaissance only in modern times. Despite his sweeping and often prophetic theories elaborated in over 60 titles¹, we know him today primarily through the few surviving fragments of his books on ethics, through the writings of a handful of proponents, and the works of his numerous detractors.

To The Manor Born

Democritus was born into considerable wealth in the Thracian city of Abdera in the north-eastern corner of Greece in around 460BC. His father was a noble with sufficient resources to entertain Xerxes's army as it passed through town on its return to Persia. The grateful emperor left behind numerous presents for the Abderians including several magi ('wise men') who would be instrumental in instructing the young Democritus in astronomy and theology. His father also arranged for him to be taught by the philosopher Leucippus (480 - 420 BC) who would introduce Democritus to an atomic theory that the younger man would later develop further.

After his father's death, Democritus used his enormous inheritance to travel the known world seeking wisdom. In addition to other Greek cities, he visited Egypt, Ethiopia, Persia, and India; eventually boasting that:

Of all my contemporaries I have covered the most ground in my travels, making the most exhaustive inquiries the while; I have seen the most climates and countries and listened to the greatest number of learned men².

After several years of travel and discovery, Democritus exhausted his patrimony and returned to Abdera where his brother Damosis took him in. Hoping to avoid the disgrace of self-inflicted poverty³, Democritus gave public lectures. He also performed experiments with herbs , plants and stones, and eventually acquired a reputation for a deep knowledge of natural phenomena. Though his lifestyle was reclusive, his talents and intelligence helped him became a man of authority and honour in Abdera.

Something from Nothing

Once back in Abdera, Democritus spent much of his time in study and in writing many dozens of books on a wide range of subjects. The central theme to all his work appears to be the atomic theory that he built by extending the ideas of his teacher Leucippus. In their system, all matter is based on immutable and indivisible basic elements (atoma, or 'indivisibles') which move about in an infinite emptiness (kenon, 'the void').

This was a revolutionary departure from the conventional thinking of the time. The dominant theory had been established at a philosophical school in Elea, founded in the early 5th Century BC by Parmenides (515 - ?BC). The central tenet of the Eleatic School was that things either exist or they do not exist; there are no intermediate states. This belief has a number of counter-intuitive implications, the most striking of which is that change is an illusion. Change implies that something can come from nothing, and since that is impossible, everything is part of one undifferentiated 'being'. The universe is one infinite motionless mass that contains no empty space - no void.

The atomist response to this was two-fold. First, since they agreed that you could not get something from nothing, they explained change as our perception of the effects of unchanging atoms in new arrangements. Second, to allow for the motion of atoms so that they could assume new positions, Democritus characterises the void as a receptacle for stationary and moving objects. In this theory, all atoms are composed of the same material, differing from each other only in shape, size, weight, and position. The movement of these assorted atomic variations results in complimentary types combining to form larger aggregations. Our perception of the variety of substances in the universe is derived from the qualities of the constituent atoms. For example, things composed of pointy atoms taste sharp or bitter, things made from small, round atoms that slip against each other feel oily, etc.

By convention sweet, by convention bitter, by convention hot, by convention cold, by convention colour: but in reality atoms and void.⁴.

Life, the Universe, and Everything

Democritus expanded on the core theory that the universe is composed of atoms moving in a void into a worldview that influenced much of his work in other fields. It was his belief that man created the gods in order to explain incomprehensible phenomena and that man invented chance to explain his mistakes. The universe, in reality, is nothing more than a complex machine that is ultimately understandable. Changes in the physical world are explained by the motion and interaction of atoms and this behaviour is subject to mathematical laws⁵. Even the human soul is composed of atoms ('globular atoms of fire') which behave according to complex mechanical processes. This theory also had implications for Democritus in the realm of ethics; it guided him to set high standards of personal integrity and social responsibility. He believed that happiness can only be achieved through discipline, moderation, acceptance, and harmony:

... the soul will either be disturbed, so that its motion affects the body in a violent way, or it will be at rest in which case it regulates thoughts and actions harmoniously. Freedom from disturbance is the condition that causes human happiness, and this is the ethical goal⁶.

Extending his theory of infinite and eternal atoms, atomic motion, and rules about how and why atoms combine to form larger structures, Democritus hypothesised an elaborate process by which stars and other worlds might form. His studies in astronomy place him among the first minds in ancient times to realise that the lights in the night sky were distant stars and that there might be other worlds.

In some worlds there is no Sun and Moon, in others they are larger than in our world, and in others more numerous. In some parts there are more worlds, in others fewer; in some parts they are arising, in others failing. There are some worlds devoid of living creatures or plants or any moisture.⁷.

An accomplished mathematician too, Democritus wrote several books: On Numbers, On Geometry, On Tangencies, On Mappings and On Irrationals, but none of these works survive.

A Long Life

Democritus lived to be approximately 100 years old⁸. In one interesting, although dubious story of the end of his life it is written that his sister became upset because his imminent death might prevent her from participating at the festival of Thesmophoria. In deference to her convenience, and using his knowledge of natural phenomena, Democritus kept himself alive by inhaling the smell of fresh baked bread. He managed to sustain himself in this manner until the festival was over three days later, after which he peacefully surrendered his life.

Legacy

In his time, Democritus was both popular and controversial - some of the greatest minds of the era built on his theories while others rejected his godless, mechanical vision of the universe. Some of his detractors may even have worked to suppress his writings. The Greek philosopher Epicurus (341 - 271 BC) constructed his own materialistic and hedonistic theory of ethics around the atomic theory of Democritus. Attributions to Democritus' ideas in Epicurus's surviving writings provide important insights into the lost works of the earlier philosopher.

Aristoxenus (364 - 304BC), a pupil of Aristotle, wrote that Plato wanted to burn all the works of Democritus but was unable to do so because the books were so popular and widely distributed. Other sources suggest that the loss of most of Democritus' writings is evidence that Plato succeeded. In either event, Plato managed to avoid any mention of Democritus in his own writings.

Though he disagreed with Democritus, Aristotle (384 - 322BC) regarded him as an important rival and had respect for his sound approach to natural philosophy. Aristotle and many of his students discuss Democritus's ideas at great length in their own works, but primarily in order to dispute them. Because of Aristotle's enormous popularity and influence, his lengthy disputations of Democritus's theories are to a large extent paradoxically responsible both for helping these ideas survive the loss of the original works and dooming them to rejection and obscurity through much of ancient and medieval times.

While never achieving the level of recognition attained by his rivals Plato or Aristotle, in modern times Democritus has managed something of a resurgence: Democritus University of Thrace is a thriving institution of higher learning, a number of private laboratories bear his name and there is a Greek coin with his image. College courses discuss Democritus's theories and even school students are required to be familiar with his ideas. To some extent, the world has come to appreciate that Democritus was an insightful genius who through observation and Einsteinian 'thought experiments' divined an almost modern theory of physics.

References and Other Reading

• 'Democritus', Humanistic Texts
• 'Democritus' by Sylvia Berryman, Stanford Encyclopedia of Philosophy
• 'Democritus (460 - 370BC.)', The Internet Encyclopedia of Philosophy
• 'The Lives and Opinions of Eminent Philosophers - Life of Democritus' by Diogenes Laertius, translated by CD Yonge, Peitho's Web