Ancient+Times

 Time-line: History of the Atom

Ancient Times (450 AD and prior year)

= Leucippus =

Origin-Miletus Asia Minor
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Leucippus is variously said to have been born in Elea, Abdera or Miletus (DK 67A1). His dates are unknown, other than that he lived during the fifth century BCE. Diogenes Laertius reports that he was a student of Parmenides' follower Zeno (DK 67A1). Zeno is best known for paradoxes suggesting that motion is impossible because a magnitude can be divided into an infinite number of parts, each of which must be traversed; the fact that atomism is thought to have been formulated in response to these arguments may account for the story that Leucippus was a student of Zeno. ======

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The Greek tradition regarded Leucippus as the founder of atomism in physics. The extent of Leucippus' contribution to the developed atomist theory is unknown. Most reports refer to the views of Democritus alone, or to both atomists together; Epicurus seems even to have denied that there was a philosopher Leucippus (DK 67A2). Aristotle certainly ascribes the foundation of the atomist system to Leucippus. Leucippus is sometimes said to have been the author of a work called the //Great World-System//; one surviving quotation is said to have come from a work On Mind. ====== [|Souce of Information 1]

= Democritus = Born- ca. 460 BCE Died- ca. 370 BCE Origin- Abdera, Thrace

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Democritus of Abdera is best known for his atomic theory but he was also an excellent geometer. Very little is known of his life but we know that Leucippus was his teacher. Although little is known of his life, quite a lot is known of his physics and philosophy. There are two main sources for our knowledge of his of physical and philosophical theories. Firstly Aristotle discusses Democritus's ideas thoroughly because he strongly disagreed with his ideas of atomism. The second source is in the work of Epicurus but, in contrast to Aristotle, Epicurus is a strong believer in Democritus's atomic theory. This work of Epicurus is preserved by Diogenes Laertius in his second century AD book.

Certainly Democritus was not the first to propose an atomic theory. His teacher Leucippus had proposed an atomic system, as had Anaxagoras of Clazomenae. In fact traces of an atomic theory go back further than this, perhaps to the Pythagorean notion of the regular solids playing a fundamental role in the makeup of the universe. However Democritus produced a much more elaborate and systematic view of the physical world than had any of his predecessors. He hypothesized that all matter is composed of tiny indestructible units, called atoms. The atoms themselves remain unchanged, but move about in space to combine in various ways to form all macroscopic objects. Early atomic theory stated that the characteristics of an object are determined by the shape of its atoms.This basically was the basis of Democritus Atomic Theory and was considered as his contribution to the atom development. [|Source of Information 1] [|Source of Information 2]

=Aristotle = Born-384 BC Died- 322 BC Origin- Stagira, Greece 

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Aristotle was born in Stagira in north Greece, the son of Nichomachus, the court physician to the Macedonian royal family. He was trained first in medicine, and then in 367 he was sent to Athens to study philosophy with Plato. He stayed at Plato's Academy until about 347 -- the picture at the top of this page, taken from Raphael's fresco //The School of Athens//, shows Aristotle and Plato (Aristotle is on the. right). Though a brilliant pupil, Aristotle opposed some of Plato's teachings, and when Plato died, Aristotle was not appointed head of the Academy. After leaving Athens, Aristotle spent some time traveling, and possibly studying biology, in Asia Minor (now Turkey) and its islands. He returned to Macedonia in 338 to tutor Alexander the Great; after Alexander conquered Athens, Aristotle returned to Athens and set up a school of his own, known as the Lyceum. After Alexander's death, Athens rebelled against Macedonian rule, and Aristotle's political situation became precarious. To avoid being put to death, he fled to the island of Euboea, where he died soon after. [|Souce of Information 1] Aristotle provided us with knowledge of natural science including Physics, which gives a vast amount of information on astronomy, meteorology, plants, and animals. Aristotle said there were only four elements (earth, air, fire, water) and that these had some smallest unit that made up all matter. Aristotle's teachings against the idea of Democritus's atom were so powerful that the idea of the atom fell out of philosophical fashion for the next 2,000 years. [|Source of Information 2] [|Source of Information 3]