Text #9167"Democritus", in .
Democritus (c. 460 – c. 370 BC) was an influential Ancient Greek pre-Socratic philosopher primarily remembered today for his formulation of an atomic theory of the universe.
Democritus was born in Abdera, Thrace around 460 BC, although, some thought it was 490 BC. His exact contributions are difficult to disentangle from those of his mentor Leucippus, as they are often mentioned together in texts. Their speculation on atoms, taken from Leucippus, bears a passing and partial resemblance to the nineteenth-century understanding of atomic structure that has led some to regard Democritus as more of a scientist than other Greek philosophers; however, their ideas rested on very different bases. Largely ignored in ancient Athens, Democritus was nevertheless well known to his fellow northern-born philosopher Aristotle. Plato is said to have disliked him so much that he wished all his books burned. Many consider Democritus to be the “father of modern science”.
Democritus was born in the city of Abdera in Thrace, an Ionian colony of Teos, although some called him a Milesian. He was born in the 80th Olympiad (460–457 BC) according to Apollodorus of Athens, and although Thrasyllus placed his birth in 470 BC, the later date is probably more likely. John Burnet has argued that the date of 460 is “too early” since, according to Diogenes Laërtius ix.41, Democritus said that he was a “young man (neos)” during Anaxagoras’ old age (circa 440–428). It was said that Democritus’ father was from a noble family and so wealthy that he received Xerxes on his march through Abdera. Democritus spent the inheritance which his father left him on travels into distant countries, to satisfy his thirst for knowledge. He traveled to Asia, and was even said to have reached India and Ethiopia.
It is known that he wrote on Babylon and Meroe; he visited Egypt, and Diodorus Siculus states that he lived there for five years. He himself declared that among his contemporaries none had made greater journeys, seen more countries, and met more scholars than himself. He particularly mentions the Egyptian mathematicians, whose knowledge he praises. Theophrastus, too, spoke of him as a man who had seen many countries. 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.
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. Leucippus, the founder of atomism, was the greatest influence upon him. He also praises Anaxagoras.
The many anecdotes about Democritus, especially in Diogenes Laërtius, attest to his disinterest, modesty, and simplicity, and show that he lived exclusively for his studies. One story has him deliberately blinding himself in order to be less disturbed in his pursuits; it may well be true that he lost his sight in old age. He was cheerful, and was always ready to see the comical side of life, which later writers took to mean that he always laughed at the foolishness of people.
He was highly esteemed by his fellow citizens, because as Diogenes Laërtius says, “he had foretold them some things which events proved to be true,” which may refer to his knowledge of natural phenomena. According to Diodorus Siculus, Democritus died at the age of 90, which would put his death around 370 BC, but other writers have him living to 104, or even 109. Marcus Aurelius, in his book Meditations, says that Democritus was eaten by lice or vermin, although in the same passage he writes that “other lice killed Socrates”, suggesting this might be metaphorical.
Most sources say that Democritus followed in the tradition of Leucippus, and they carried on the scientific rationalist philosophy associated with Miletus. Both were thoroughly materialist, believing everything to be the result of natural laws. Unlike Aristotle or Plato, the atomists attempted to explain the world without reasoning as to purpose, prime mover, or final cause. For the atomists questions of physics should be answered with a mechanistic explanation (“What earlier circumstances caused this event?”), while their opponents search for explanations which, in addition to the material and mechanistic, also included the formal and teleological (“What purpose did this event serve?”).
The theory of Democritus held that everything is composed of “atoms”, which are physically, but not geometrically, indivisible; that between atoms, there lies empty space; that atoms are indestructible; have always been, and always will be, in motion; that there are an infinite number of atoms, and kinds of atoms, which differ in shape, and size. Of the mass of atoms, Democritus said “The more any indivisible exceeds, the heavier it is.” But his exact position on weight of atoms is disputed.
Leucippus is widely credited with being the first to develop the theory of atomism, although Isaac Newton preferred to credit the obscure Mochus the Phoenician (whom he believed to be the biblical Moses) as the inventor of the idea on the authority of Posidonius and Strabo. However, the Stanford Encyclopedia of Philosophy notes, “This theologically motivated view does not seem to claim much historical evidence, however.”
Democritus, along with Leucippus and Epicurus, proposed the earliest views on the shapes and connectivity of atoms. They reasoned that the solidness of the material corresponded to the shape of the atoms involved. Thus, iron atoms are solid and strong with hooks that lock them into a solid; water atoms are smooth and slippery; salt atoms, because of their taste, are sharp and pointed; and air atoms are light and whirling, pervading all other materials. Using analogies from our sense experiences, he gave a picture or an image of an atom that distinguished them from each other by their shape, their size, and the arrangement of their parts. Moreover, connections were explained by material links in which single atoms were supplied with attachments: some with hooks and eyes others with balls and sockets. The Democritean atom is an inert solid (merely excluding other bodies from its volume) that interacts with other atoms mechanically. In contrast, modern, quantum-mechanical atoms interact via electric and magnetic force fields and are far from inert.
The theory of the atomists appears to be more nearly aligned with that of modern science than any other theory of antiquity. However, the similarity with modern concepts of science can be confusing when trying to understand where the hypothesis came from. It is obvious that classical atomists would never have had a solid empirical basis for our modern concepts of atoms and molecules. Bertrand Russell states that they just hit on a lucky hypothesis, only recently confirmed by evidence.
However, Lucretius, describing atomism in his De rerum natura, gives very clear and compelling empirical arguments for the original atomist theory. He observes that any material is subject to irreversible decay. Through time, even hard rocks are slowly worn down by drops of water. Things have the tendency to get mixed up: mix water with soil and you get mud, that will usually not un-mix by itself. Wood decays. However, we see in nature and technology that there are mechanisms to recreate “pure” materials like water, air, and metals. The seed of an oak will grow out into an oak tree, made of similar wood as historical oak trees, the wood of which has already decayed. The conclusion is that many properties of materials must derive from something inside, that will itself never decay, something that stores for eternity the same inherent, indivisible properties. The basic question is: why has everything in the world not yet decayed, and how can exactly the same materials, plants, animals be recreated again and again? One obvious solution to explain how indivisible properties can be conveyed in a way not easily visible to human senses, is to hypothesize the existence of “atoms”. These classical “atoms” are nearer to our modern concept of “molecule” than to the atoms of modern science. The other big point of classical atomism is that there must be a lot of open space between these “atoms”: the void. Lucretius gives reasonable arguments that the void is absolutely necessary to explain how gasses and liquids can change shape, flow, while metals can be molded, without changing the basic material properties.
The atomistic void hypothesis was a response to the paradoxes of Parmenides and Zeno, the founders of metaphysical logic, who put forth difficult to answer arguments in favor of the idea that there can be no movement. They held that any movement would require a void—which is nothing—but a nothing cannot exist. The Parmenidean position was “You say there is a void; therefore the void is not nothing; therefore there is not the void.” The position of Parmenides appeared validated by the observation that where there seems to be nothing there is air, and indeed even where there is not matter there is something, for instance light waves.
The atomists agreed that motion required a void, but simply ignored the argument of Parmenides on the grounds that motion was an observable fact. Therefore, they asserted, there must be a void. This idea survived in a refined version as Newton’s theory of absolute space, which met the logical requirements of attributing reality to not-being. Einstein’s theory of relativity provided a new answer to Parmenides and Zeno, with the insight that space by itself is relative and cannot be separated from time as part of a generally curved space-time manifold. Consequently, Newton’s refinement is now considered superfluous.
The knowledge of truth, according to Democritus, is difficult, since the perception through the senses is subjective. As from the same senses derive different impressions for each individual, then through the sense-impressions we cannot judge the truth. We can only interpret the sense data through the intellect and grasp the truth, because the truth is at the bottom.
There are two kinds of knowing, the one he calls “legitimate” (γνησίη, gnesie, “genuine”) and the other “bastard” (σκοτίη, skotie, “secret”). The “bastard” knowledge is concerned with the perception through the senses, therefore it is insufficient and subjective. The reason is that the sense-perception is due to the effluences of the atoms from the objects to the senses. When these different shapes of atoms come to us, they stimulate our senses according to their shape, and our sense-impressions arise from those stimulations.
The second sort of knowledge, the “legitimate” one, can be achieved through the intellect, in other words, all the sense-data from the “bastard” must be elaborated through reasoning. In this way one can get away from the false perception of the “bastard” knowledge and grasp the truth through the inductive reasoning. After taking into account the sense-impressions, one can examine the causes of the appearances, draw conclusions about the laws that govern the appearances, and discover the causality (αἰτιολογία, aetiologia) by which they are related. This is the procedure of thought from the parts to the whole or else from the apparent to non-apparent (inductive reasoning). This is one example of why Democritus is considered to be an early scientific thinker.
Vlastos, Gregory (1945/1946). “Ethics and Physics in Democritus”. Philosophical Review. 54/55: 578–592, 53–64.