Editing Leucippus (section)

== Legacy ==
[[File:Leucippus. Line engraving by S. Beyssent after Mlle C. Reyde Wellcome V0003528.jpg|thumb|upright|alt=A line engraving of Leucippus|A 1773 [[line engraving]] of Leucippus]]

=== Ancient Greece ===
Modern understanding of Leucippus's role in the development of atomism comes from the writings of the ancient Greek philosophers Aristotle and [[Theophrastus]].{{Sfn|Graham|2008|p=333}} Aristotle's 4th-century BCE record of Leucippus and Democritus's philosophy is the oldest surviving source on the subject,{{Sfn|Hasper|2014|p=65}} though he did not distinguish who developed which atomist ideas.{{Sfn|Skordoulis|Koutalis|2013|pp=467–468}}{{Sfn|Gregory|2020|pp=23–24}} Aetius also wrote about Leucippus, but it was well after Leucippus's own time and derivative of previous writings on the subject.{{Sfn|Graham|2008|p=337}} Some later histories of philosophy omitted Leucippus entirely.{{Sfn|Taylor|1999|p=181}} Since ancient times, Leucippus has languished in obscurity compared to Democritus,{{Sfn|Skordoulis|Koutalis|2013|p=467}}{{Sfn|Taylor|1999|pp=181–182}} and since the earliest records of atomist thought, it has been common practice to consider the ideas of Leucippus and Democritus collectively rather than attempting to distinguish them.{{Sfn|Skordoulis|Koutalis|2013|pp=467–468}}{{Sfn|Gregory|2020|pp=23–24}}

The atomist philosophy of Leucippus and Democritus influenced Greek philosophy for centuries, particularly in the work of Aristotle and Epicurus.{{Sfn|Taylor|1999|pp=199–200}} Aristotle was critical of atomism. He questioned why stone should fall but fire should rise if they are both made of the same material.{{Sfn|Furley|1987|p=184}} According to [[Diogenes Laertius]], [[Diogenes of Apollonia]]'s interpretation of the void may have been inspired by Leucippus.{{Sfn|Barnes|2012|p=569}}{{Sfn|Stokes|1971|p=243}} [[Plato]] explored cosmological ideas similar to those of Leucippus in the dialogue ''[[Timaeus (dialogue)|Timaeus]]''.{{Sfn|Gregory|2013|p=449}}

=== Modern era ===
Ancient atomism was revived in the 16th and 17th centuries,{{Sfn|Gregory|2020|p=26}}{{Sfn|Taylor|1999|pp=219–220}} especially by proponents of the [[mechanical philosophy]] such as [[Pierre Gassendi]] (1592–1655) and [[Robert Boyle]] (1627–1691).{{sfn|Chalmers|2005–2014}} Nevertheless, in practice experimental chemists such as Boyle rather relied on the tradition of [[corpuscularianism]] which had developed in medieval [[alchemy]] and ultimately goes back to works such as Aristotle's [[Meteorology (Aristotle)|''Meteorology IV'']].{{sfn|Berryman|2005–2022}} Throughout the 18th century chemists worked independently from philosophical atomism, which only changed when [[John Dalton]] (1766–1844) proposed a form of atomism that was rooted in chemical experiment.{{sfn|Chalmers|2005–2014}}

Although Leucippus' ideas form an important historical precedent for the concept of atoms in general, they only bear a superficial resemblance to modern [[atomic theory]]. Leucippus's philosophy was conjecture based on ''[[a priori]]'' evidence, while modern atomic theory is supported by empirical evidence found through the [[scientific method]].{{Sfn|McKirahan|2011|pp=341–342}}{{Sfn|Barnes|2012|pp=343–344}} The main practical difference between Leucippus's atomism and modern atomic theory is the introduction of non-tangible phenomena such as [[mass–energy equivalence]] and [[fundamental force]]s. Instead of the purely material atoms of Leucippus, modern atomic theory shows that fundamental forces combine [[subatomic particle]]s into atoms and link atoms together into [[molecule]]s.{{Sfn|McKirahan|2011|p=342}} The 20th-century physicist [[Werner Heisenberg]] argued that Plato's [[theory of forms]] was closer to the 20th-century understanding of physics than Leucippus's conception of atoms, saying that modern atoms are more like the intangible Platonic forms than the discrete material units of Leucippus.{{Sfn|Barnes|2012|p=344}}

==== Scholarship on Leucippus ====

Modern philosophy generally takes more interest in Leucippus's concept of atoms than his cosmology.{{Sfn|Graham|2008|p=344}} Two major systems have been created to distinguish Leucippus and Democritus. The 20th-century philosopher {{Ill|Adolf Dyroff|de}} developed a set of distinctions between Leucippus and Democritus: he proposed that Leucippus was responsible for the atomist response to the Eleatics while Democritus responded to the [[Sophists]] and that Leucippus was a cosmologist while Democritus was a [[polymath]].{{Sfn|Graham|2008|p=335}} The 20th-century classicist [[Cyril Bailey]] proposed another system to differentiate the two philosophers, attributing atomism and belief in the void to Leucippus while attributing ''The Great Cosmology'' to Democritus as an application of Leucippus's philosophy.{{Sfn|Graham|2008|p=336}} Unlike Democritus, Leucippus is only known to have studied cosmology and physics.{{Sfn|Hasper|2014|p=65}}

=== Historicity ===
According to Diogenes Laertius, Epicurus alleged that Leucippus never existed—an allegation that triggered extensive philosophical debate.{{Sfn|Skordoulis|Koutalis|2013|p=467}}{{Sfn|Graham|2008|p=334}} Most modern philosophers agree that Leucippus existed, but there is disagreement on whether his work can be meaningfully distinguished from that of Democritus.{{Sfn|Graham|2008|p=337}} In 2008, the philosopher Daniel Graham wrote that no significant work on the historicity of Leucippus has been produced since the early 20th century, arguing that "recent scholarship tends to avoid the question as much as possible".{{Sfn|Graham|2008|p=333}}

Scholars who maintain that Leucippus existed argue that he only taught orally or that any written works he produced were never meant for publication.{{Sfn|Graham|2008|p=335}} The 20th-century classicist John Burnet proposed an alternate reading of Epicurus's claims, according to which Epicurus may have been saying that Leucippus was not worth discussing as a philosopher, not that he literally did not exist.{{Sfn|Kirk|Raven|1957|p=402}} Supporting this argument is that Epicurus considered ethics to be foundational to philosophy, and Leucippus had no teachings on that subject.{{Sfn|Cerri|2016|p=21}} Among scholars who argue against Leucippus's existence, alternate ideas have been proposed: Leucippus may have been a pseudonym of Democritus, or he may have been a character in a [[Socratic dialogue|dialogue]].{{Sfn|Graham|2008|p=335}} Modern scholars who have rejected the existence of Leucippus include [[Erwin Rohde]], [[Paul Natorp]], [[Paul Tannery]], P. Bokownew, {{ill|Ernst Howald|de}}, {{ill|Herman De Ley|qid=Q55233263}},{{Sfn|Graham|2008|p=337}} {{ill|Adolf Brieger|de}}, and [[Wilhelm Nestle]].{{Sfn|Cerri|2016|p=13}}

The existence of Leucippus was an issue in 19th-century German philosophy, where it spawned a debate between Rohde, Natorp, and [[Hermann Alexander Diels]]. Rhode believed that even in the time of Epicurus there was no evidence of Leucippus's existence, and there was therefore no purpose in attributing the atomism of Democritus to an unknown figure such as Leucippus, rejecting Theophrastus's account. Natorp likewise rejected that Diogenes of Apollonia was preceded by Leucippus. Diels affirmed the account of Theophrastus and produced writings criticizing Rhode and Natorp.{{Sfn|Graham|2008|pp=334–335}} The problem was significant enough that it was given its own name in German: {{Lang|de|die Leukipp-frage}} ({{Translation|''the Leucippus problem''}}).{{Sfn|Cerri|2016|p=13}}{{Sfn|Graham|2008|pp=333, 348n1}}