Editing Democritus (section)

===Atomism===
{{see also|Atomism}}
It was Democritus who, in his numerous writings, carried out Leucippus's theory of atoms, and especially in his observations on nature. These atomists undertook the task of proving that the quantitative relations of matter were its original characteristics, and that its qualitative relations were something secondary and derivative, and of thus doing away with the distinction between matter and mind or power. <ref>(Brandis, l.c. p. 294.)</ref> In order to avoid the difficulties connected with the supposition of primitive matter with definite qualities, without admitting the coming into existence and annihilation as realities, and without giving up, as the Eleatic philosophers did, the reality of variety and its changes, the atomists derived all definiteness of phaenomena, both physical and mental, from elementary particles, the infinite number of which were homogeneous in quality, but heterogeneous in form. This made it necessary for them to establish the reality of a vacuum or space, and of motion. <ref>(Brandis, l.c. p. 303, &c.</ref>) Motion, they said, is the eternal and necessary consequence of the original variety of atoms in the vacuum or space. All phaenomena arise from the infinite variety of the form, order, and position of the atoms in forming combinations. It is impossible, they add, to derive this supposition from any higher principle, for a beginning of the infinite is inconceivable. <ref>(Aristot. de Generat. Anim. 2.6, p. 742b. 20, ed. Bekker; Brandis, l.c. p. 309, &c.c.)</ref> The atoms are impenetrable, and therefore offer resistance to one another. This creates a swinging, world-producing, and whirling motion. (This reminds us of the joke in the Clouds of [[Aristophanes]] about the god Δῖνος !) Now as similars attract one another, there arise in that motion real things and beings, that is, combinations of distinct atoms, which still continue to be separated from one another by the vacuum. The first cause of all existence is necessity, that is, the necessary predestination and necessary succession of cause and effect. This they called chance, in opposition to the νοῦς of Anaxagoras. But it does the highest honour to the mind of Democritus, that he made the discovery of causes the highest object of scientific investigations. He once said, that he preferred the discovery of a true cause to the possession of the kingdom of Persia. <ref>(Dionys. Alex. apud Euseb. Praep. Evang. 14.27.)</ref> We must not, therefore, take the word chance (τυχή) in its vulgar acceptation. <ref>(Brandis, l.c. p. 319.)</ref> Aristotle understood Democritus rightly in this respect, <ref>(Phys. Auscult. 2.4, p. 196. 11; Simplic. fol. 74)</ref> as he generally valued him highly, and often says of him, that he had thought on all subjects, searched after the first causes of phenomena, and endeavored to find definitions. <ref>(De Generat. et Corrupt. 1.2, 8, Metaph. M. 4, Phys. 2.2, p. 194, 20, de Part. Anim. i. p. 642, 26.)</ref> The only thing for which he censures him, is a disregard for teleological relations, and the want of a comprehensive system of induction. <ref>(De Respir. 4, de Generat. Anim. 5.8.)</ref> Democritus himself called the common notion of chance a cover of human ignorance (πρόφα-σιν ἰδίης ἀνοίης), and an invention of those who were too idle to think.<ref>(Dionys. apud Euseb. Praep. Evang. 14.27; Stob. Eclog. Eth. p. 344.)</ref><ref>{{cite DGRBM|title=Democritus|url = https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0104%3Aentry%3Ddemocritus-bio-2}}</ref>

Democritus held that originally the universe was composed of nothing but tiny atoms churning in chaos, until they collided together to form larger units—including the earth and everything on it.{{sfn|Barnes|1987}} He surmised that [[Cosmic pluralism|there are many worlds]], some growing, some decaying; some with no sun or moon, some with several. He held that every world has a beginning and an end and that a world could be destroyed by collision with another world.{{efn|To epitomize Democritus's cosmology, Russell{{sfn|Russell|1972|pp=71–72}} calls on Shelley: "Worlds on worlds are rolling ever / From creation to decay, / Like the bubbles on a river / Sparkling, bursting, borne away".}}He concluded that divisibility of matter comes to an end, and the smallest possible fragments must be bodies with sizes and shapes, although the exact argument for this conclusion of his is not known. The smallest and indivisible bodies he called "atoms".<ref name="Kenny" /> 

Atoms, Democritus believed, are too small to be detected by the senses; they are infinite in numbers and come in infinitely many varieties, and they have existed forever and that these atoms are in constant motion in the void or vacuum. The middle-sized objects of everyday life are complexes of atoms that are brought together by random collisions, differing in kind based on the variations among their constituent atoms.<ref name="Kenny" /> For Democritus, the only true realities are atoms and the void. What we perceive as water, fire, plants, or humans are merely combinations of atoms in the void. The sensory qualities we experience are not real; they exist only by convention.<ref name=":2" /> Of the mass of atoms, Democritus said, "The more any indivisible exceeds, the heavier it is." However, his exact position on atomic weight is disputed.{{sfn|Russell|1972|p=64–65}}

The [[The Void (philosophy)|atomistic void]] hypothesis was a response to the paradoxes of [[Parmenides]] and [[Zeno of Elea|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."{{sfn|Russell|1972|p=69}}<ref>Aristotle, ''Phys''. iv.6</ref> 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 rejected the argument of Parmenides on the grounds that motion was an observable fact. Therefore, they asserted, there must be a void.

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 19th-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.{{sfn|Berryman|2016}} 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.{{sfn|Berryman|2016}} Using analogies from humans' [[empirical evidence|sense experience]]s, 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.<ref>See ''testimonia'' DK 68 A 80, DK 68 A 37 and DK 68 A 43.</ref>

Besides the infinite number of atoms existing in infinite space, Democritus also supposed the existence of an infinite number of worlds, some of which resembled one another, while others differed from one another, and each of these worlds was kept together as one thing by a sort of shell or skin. He derived the four elements from the form of the atoms predominating in each, from their quality, and their relations of magnitude. In deriving individual things from atoms, he mainly considered the qualities of warm and cold. The warm or firelike he took to be a combination of fine, spheric, and very movable atoms, as opposed to the cold and moist. His mode of proceeding, however, was, first carefully to observe and describe the phaenomena themselves, and then to attempt his atomistic explanation, whereby he essentially advanced the knowledge of nature.<ref>Papencordt, l.c. p. 45, &c.; Brandis, l.c. p. 327.</ref> He derived the soul, the origin of life, consciousness, and thought, from the finest fire-atoms;<ref>Aristot. de An. 1.2, ed. Trendelenburg</ref> and in connexion with this theory he made very profound physiological investigations. It was for this reason that, according to him, the soul while in the body acquires perceptions and knowledge by corporeal contact, and that it is affected by heat and cold. The sensuous perceptions themselves were to him affections of the organ or of the subject perceiving, dependent on the changes of bodily condition, on the difference of the organs and their quality, on air and light. Hence the differences, e. g., of taste, color, and temperature, are only conventional,<ref>Sext. Empir. ad v. Math. 7.135</ref> the real cause of those differences being in the atoms.<ref>{{cite DGRBM|title=Democritus|url = https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0104%3Aentry%3Ddemocritus-bio-2}}</ref>