Editing Leucippus (section)

=== Soul and perception ===
Leucippus and Democritus proposed that heat, fire, and the [[soul]] are made of spherical atoms, as this shape would let them move past one another and cause the others to move more efficiently. They believed in a physical soul that drives motion in living things, and they described respiration as the process of expelling soul atoms and absorbing new ones.{{Sfn|Augustin|Pellò|2021|pp=615–616}} Death then coincides with the last breath, as soul atoms are no longer being replenished. Sleep is a similar state in which a reduced number of soul atoms are in the body.{{Sfn|Augustin|Pellò|2021|pp=617–618}}

Leucippus was the first philosopher to describe a [[Philosophy of mind|theory of thought]] and [[Philosophy of perception|perception]].{{Sfn|McKirahan|2011|p=332}} He described sensory input as a transfer between atoms, created when external atoms come into contact with the atoms of the soul.{{Sfn|McKirahan|2011|p=329}} Leucippus said that sight is caused by a film of atoms emitted from an object, maintaining the shapes of its atoms and creating a reflection of the object in the viewer's eye. His description of vision was inspired by [[Empedocles]], who formed a similar concept of objects emitting films of themselves.{{Sfn|McKirahan|2011|p=330}} Leucippus posited that concepts such as color and texture are created by different arrangements of atoms, and that abstract concepts such as [[justice]] and [[wisdom]] are produced through the arrangement of soul atoms.{{Sfn|Furley|1987|p=171}}

According to Epiphanius, Leucippus said that reasoned [[knowledge]] is impossible to obtain and only unreasoned [[belief]] exists.{{Sfn|Barnes|2012|p=562}} The 20th-century writer Constantine Vamvacas said that Leucippus rejected this belief, and that it was the Eleatic philosopher Parmenides who held it. According to Vamvacas, Leucippus and Democritus "believe that sense experience, however limited, constitutes objective knowledge of the physical world".{{Sfn|Vamvacas|2009|p=211}} The 20th-century scholar C. C. W. Taylor said that "we have no evidence to suggest that Leucippus was concerned with [[epistemological]] questions".{{Sfn|Taylor|1999|p=189}}