Editing Leucippus (section)

=== Atoms ===
Leucippus is credited with developing the philosophical school of [[atomism]]. He proposed that all things are made up of microscopic, indivisible particles that interact and combine to produce all the things of the world.{{Sfn|Skordoulis|Koutalis|2013|p=467}}{{Sfn|Taylor|1999|pp=181–182}} The atoms postulated by Leucippus come in infinitely many shapes and sizes, although the size and shape of each atom is fixed and unchanging. They are in a state of constant motion and continuously change arrangements with one another.{{Sfn|Zilioli|2020|p=4}}{{Sfn|Barnes|2012|pp=365–366, 440}} He reasoned that there must be infinite types of atoms because there is no reason why there should not be.{{Sfn|Gregory|2020|pp=24, 452}}{{Sfn|Barnes|2012|pp=363–365}}

According to the 4th-century BCE philosopher [[Aristotle]], Leucippus argued that logically there must be indivisible points in everything. His reasoning was that if an object was made entirely of divisible points, then it would not have any structure and it would be intangible.{{Sfn|Hasper|2014|p=66}}{{Sfn|Barnes|2012|p=360}} Leucippus developed atomism along with his student, [[Democritus]];{{Sfn|Skordoulis|Koutalis|2013|p=467}}{{Sfn|Taylor|1999|pp=181–182}} while Leucippus is credited with the philosophy's creation, Democritus is understood to have elaborated upon it and applied it to natural phenomena.{{Sfn|McKirahan|2011|p=304}}

Two works are attributed to Leucippus: ''The Great World System'' and ''On Mind''.{{Sfn|Skordoulis|Koutalis|2013|p=467}}{{Sfn|Graham|2008|p=334}} The former may have originally been titled ''The World System'' and then later renamed to avoid confusion with Democritus's ''The Little World System''. Leucippus's ''The Great World System'' has sometimes been attributed to Democritus.{{Sfn|Cerri|2016|pp=15–16}} Only one extant [[Literary fragment|fragment]] is attributed to Leucippus, taken from ''On Mind'': "Nothing happens at random, but everything for a reason and by necessity".{{Sfn|Gregory|2020|p=34}}{{Sfn|Vamvacas|2009|p=218}} Leucippus believed that all things must happen [[Determinism|deterministically]], as the positions and motions of the atoms guarantee that they will collide in a certain way,{{Sfn|McKirahan|2011|p=320}}{{Sfn|Kirk|Raven|1957|p=418}} invoking the [[principle of causality]].{{Sfn|Barnes|2012|p=413}} This was reminiscent of the 6th-century BCE philosopher [[Anaximander]]'s argument that movement is created by differences, and it was later codified by the 17th-century philosopher [[Gottfried Wilhelm Leibniz]] with the [[principle of sufficient reason]].{{Sfn|Vamvacas|2009|p=40}} Leucippus rejected the idea that there was an intelligent force governing the universe.{{Sfn|Barnes|2012|p=414}}