Editing Empedocles (section)

===Psychology===
Like [[Pythagoras]], Empedocles believed in the [[transmigration of the soul]] or [[metempsychosis]], that souls can be reincarnated between humans, animals and even plants.{{efn|Frag. B127 (Aelian, ''On Animals'', xii. 7); Frag. B117 (Hippolytus, i. 3.2)}} According to him, all humans, or maybe only a selected few among them,{{sfn|Inwood|2001|pp=55–68}} were originally long-lived [[daimon]]s who dwelt in a state of bliss until committing an unspecified crime, possibly bloodshed or perjury.{{sfn|Inwood|2001|pp=55–68}}{{sfn|Primavesi|2008|pp=261–268}} As a consequence, they fell to Earth, where they would be forced to spend 30,000 cycles of metempsychosis through different bodies before being able to return to the sphere of [[divinity]].{{sfn|Inwood|2001|pp=55–68}}{{sfn|Primavesi|2008|pp=261–268}} One's behavior during his lifetime would also determine his next incarnation.{{sfn|Inwood|2001|pp=55–68}} Wise people, who have learned the secret of life, are closer to the divine,{{sfn|Wallace|1911}}{{efn|Clement of Alexandria, ''Miscellanies'', iv. 23.150}} while their souls similarly are closer to the freedom from the cycle of reincarnations, after which they are able to rest in happiness for eternity.{{efn|Clement of Alexandria, ''Miscellanies'', v. 14.122}} This cycle of mortal incarnation seems to have been inspired by the god [[Apollo]]'s punishment as a servant to [[Admetus of Pherae|Admetus]].{{sfn|Primavesi|2008|pp=261–268}}

[[File:AGMA Clepsydre.jpg|thumb|right|A display of two 5th century BCE clepsydras, or "water clocks" from the Ancient Agora Museum in Athens]]

Empedocles was a [[vegetarianism|vegetarian]]{{efn|Plato, Meno}}{{better source needed|date=September 2022}} and advocated vegetarianism, since the bodies of animals are also dwelling places of punished souls.{{efn|Sextus Empiricus, ''Against the Mathematicians'', ix. 127; Hippolytus, vii. 21}} For Empedocles, all living things were on the same spiritual plane; plants and animals are links in a chain where humans are a link too.{{sfn|Wallace|1911}}

Empedocles is credited with the first comprehensive theory of light and vision. Historian [[Will Durant]] noted that "Empedocles suggested that light takes time to pass from one point to another."<ref>Durant, Will. ''[[The Story of Civilization]]'', Volume 2: ''The Life of Greece'' (New York; Simon & Schuster) 1939, p. 339.</ref>{{better source needed|date=September 2022}} He put forward the idea that we see objects because light streams out of our eyes and touches them. While flawed, this became the fundamental basis on which later Greek philosophers and mathematicians like [[Euclid]] would construct some of the most important theories of light, vision, and optics.<ref name = Ep1>''[[Light Fantastic (TV series)|Let There be Light]]'' 7 August 2006 01:50 BBC Four</ref>{{better source needed|date=September 2022}}

Knowledge is explained by the principle that elements in the things outside us are perceived by the corresponding elements in ourselves.{{efn|Frag. B109 (Aristotle, ''On the Soul'', 404b11–15)}} Like is known by like. The whole body is full of [[Sweat gland|pores]] and hence [[Cellular respiration|respiration]] takes place over the whole frame. In the organs of sense these pores are specially adapted to receive the effluences which are continually rising from bodies around us; thus [[perception]] occurs.{{efn|Frag. B100 (Aristotle, ''On Respiration'', 473b1–474a6)}} In vision, certain particles go forth from the eye to meet similar particles given forth from the object, and the resultant contact constitutes vision.{{efn|Frag. B84 (Aristotle, ''On the Senses and their Objects'', 437b23–438a5)}} Perception is not merely a passive reflection of external objects.<ref>{{Cite web|url=https://theodora.com/encyclopedia/e/empedocles.html|title=Empedocles – Encyclopedia}}</ref>{{better source needed|date=September 2022}}

Empedocles also attempted to explain the phenomenon of [[Respiration (physiology)|respiration]] by means of an elaborate analogy with the [[Water clock|clepsydra]], an ancient device for conveying liquids from one vessel to another.{{efn| Aristotle, On Respiration 13}}{{sfn|Barnes|2002|p=313}} This fragment has sometimes been connected to a passage{{efn|Aristotle, ''Physics'', 213a24–7}} in [[Aristotle]]'s ''[[Physics (Aristotle)|Physics]]'' where Aristotle refers to people who twisted wineskins and captured air in clepsydras to demonstrate that [[Vacuum|void]] does not exist. The fragment certainly implies that Empedocles knew about the [[Matter|corporeality]] of air, but he says nothing whatever about the void, and there is no evidence that Empedocles performed any experiment with clepsydras.{{sfn|Barnes|2002|p=313}}