Democritus was an Ancient Greek pre-Socratic philosopher. He remains a central figure in the development of philosophical atomism and of the atomic theory of the universe.
Background
Democritus was born c. 460 B.C., though some historians argued that he was born c. 440-428 B.C. since he called himself a "young man" during Anaxagoras' old age. It seems that he was a citizen of Abdera in Thrace, an Ionian colony of Teos. It was said that Democritus' father was from a noble family and so wealthy that he received Xerxes on his march through Abdera, and that he spent the inheritance which his father left him on travels into distant countries to satisfy his thirst for knowledge.
Education
Democritus' only certainly attested teacher was Leucippus. During his travels, according to Diogenes Laërtius, he became acquainted with the Chaldean magi. "Ostanes," one of the magi accompanying Xerxes, was also said to have taught him.
Career
It is known that Democritus wrote on Babylon and Meroe; he visited Egypt, and Diodorus Siculus states that he lived there for five years. After returning to his native land he occupied himself with natural philosophy. He traveled throughout Greece to acquire a better knowledge of its cultures. He mentions many Greek philosophers in his writings, and his wealth enabled him to purchase their writings.
According to Diogenes Laërtius, his works numbered 73; the titles of more than sixty writings are preserved from a catalog that probably represented the holdings of the library at Alexandria. Only some 300 alleged quotations now exist, many of which may not be genuine.
Later Greek historians consider Democritus to have established aesthetics as a subject of investigation and study, as he wrote theoretically on poetry and fine art long before authors such as Aristotle. Specifically, Thrasyllus identified six works in the philosopher's oeuvre which had belonged to aesthetics as a discipline, but only fragments of the relevant works are extant; hence of all Democritus's writings on these matters, only a small percentage of his thoughts and ideas can be known.
According to Diodorus Siculus, Democritus died at the age of 90, which would put his death around 370 B.C., but other writers have him living to 104, or even 109.
Religion
Democritus attributed popular belief in the gods to a desire to explain extraordinary phenomena (thunder, lightning, earthquakes) by reference to superhuman agency.
Politics
Most of the fragments dealing with political questions are as traditional in content as those dealing with ethics. Democritus seems to have had no doubts about the importance of law, although its function was limited to preventing one man from injuring another. It is inferior to encouragement and persuasion, but "it is right to obey the law, the ruler and the man who is wiser."
Views
To account for the world’s changing physical phenomena, Democritus asserted that space, or the Void, had an equal right with reality, or Being, to be considered existent. He conceived of the Void as a vacuum, an infinite space in which moved an infinite number of atoms that made up Being (the physical world). These atoms are eternal and indivisible; absolutely small, so small that their size cannot be diminished; absolutely full and incompressible, as they are without pores and entirely fill the space they occupy; and homogeneous, differing only in shape, arrangement, position, and magnitude. But, while atoms thus differ in quantity, differences of quality are only apparent, owing to the impressions caused on the senses by different configurations and combinations of atoms. A thing is hot or cold, sweet or bitter, or hard or soft only by convention; the only things that exist in reality are atoms and the Void. Thus, the atoms of water and iron are the same, but those of water, being smooth and round and therefore unable to hook onto one another, roll over and over like small globes, whereas those of iron, being rough, jagged, and uneven, cling together and form a solid body.
Because all phenomena are composed of the same eternal atoms, it may be said that nothing comes into being or perishes in the absolute sense of the words, although the compounds made out of the atoms are liable to increase and decrease, explaining a thing’s appearance and disappearance, or “birth” and “death.”
Just as the atoms are uncaused and eternal, so too, according to Democritus, is motion. He posited the fixed and “necessary” laws of a purely mechanical system, in which there was no room for an intelligent cause working toward an end. He explained the origin of the universe as follows. The original motion of the atoms was in all directions - it was a sort of “vibration”; hence there resulted collisions and, in particular, a whirling movement, whereby similar atoms were brought together and united to form larger bodies and worlds. This happened not as the result of any purpose or design but rather merely as the result of “necessity”; i.e., it is the normal manifestation of the nature of the atoms themselves. Atoms and void being infinite in number and extent, and motion having always existed, there must always have been an infinite number of worlds, all consisting of similar atoms in various stages of growth and decay.
Sensation for Democritus was based upon touch and was due to images entering the sense organs from outside and producing alterations in the percipient. Sensation is thus the result of the interaction of image and organ. In the case of flavors, there is always a multitude of configurations of atoms present in what is tasted, but the preponderant configuration exerts the greatest influence and determines the flavor tasted, the result being influenced also by the state of the sense organs. In the case of sight, images continually stream off the objects, which are somehow imprinted - by stamping, as it were - on the intervening air. This imprinted air is then carried to the eyes, where its configuration produces the sensation of color. A similar analysis seems to have been offered for hearing and perhaps for smell. Taste, however, entails direct contact between organ and object: large, rough, polygonal shapes produce astringent flavors, and so on.
Democritus did claim that there were two kinds of knowledge, one genuine or legitimate, and the other bastard. To the bastard belong the senses; genuine knowledge operates on objects too fine for any sense to grasp.
He treated the sphere as “all angle,” and Simplicius explained this as meaning that what is bent is an angle and the sphere is bent all over. It is inferred that he supposed that the sphere is really a polyhedron with imperceptibly small faces, presumably because a physical sphere involves atoms which cannot be further broken down.
Quotations:
"Happiness resides not in possessions, and not in gold, happiness dwells in the soul."
"Nothing exists except atoms and empty space; everything else is opinion."
"By desiring little, a poor man makes himself rich."
"It is greed to do all the talking but not to want to listen at all."
"Do not trust all men, but trust men of worth; the former course is silly, the latter a mark of prudence."
"Our sins are more easily remembered than our good deeds."
"If thou suffer injustice, console thyself; the true unhappiness is in doing it."
"Good means not merely not to do wrong, but rather not to desire to do wrong."
"It is better to destroy one's own errors than those of others."
"Men should strive to think much and know little."
"I would rather discover one true cause than gain the kingdom of Persia."
"Everything existing in the universe is the fruit of chance and necessity."
"The wrongdoer is more unfortunate than the man wronged."
"It is godlike ever to think on something beautiful and on something new."
"Medicine heals diseases of the body, wisdom frees the soul from passions."
"Man is a universe in little."
"Immoderate desire is the mark of a child, not a man."
"Education is an ornament for the prosperous, a refuge for the unfortunate."
"The animal needing something knows how much it needs, the man does not."
"The brave man is not only he who overcomes the enemy, but he who is stronger than pleasures. Some men are masters of cities, but are enslaved to women."
Personality
Democritus was cheerful, and was always ready to see the comical side of life. The many anecdotes about him attest to his disinterest, modesty, and simplicity, and show that he lived exclusively for his studies.
From Cicero and Horace we learn that - at least in their time - he was known as the “laughing philosopher” because of his amusement at the follies of mankind.
He declared that among his contemporaries none had made greater journeys, seen more countries, and met more scholars than himself.
Largely ignored in ancient Athens, Democritus is said to have been disliked so much by Plato that the latter wished all of his books burned.
Physical Characteristics:
Democritus lost his sight in old age; one story has him deliberately blinding himself in order to be less disturbed in his pursuits.
Quotes from others about the person
Diogenes Laërtius: "Democritus had foretold us some things which events proved to be true."
Karl R. Popper: "Democritus formulated the doctrine that human institutions of language, custom, and law are not taboos but man-made, not natural but conventional, insisting, at the same time, that we are responsible for them."