{{Short description|Natural philosophy holding that the world comprises fundamental indivisible components}}
{{About|the natural philosophy regarding the fundamental composition of the physical world}}
'''Atomism''' ({{etymology|grc|''ἄτομον'' (atomon)|uncuttable, indivisible}})[{{LSJ|a)/tomos|ἄτομον|ref}}][{{cite OEtymD|atom}}][The term 'atomism' is recorded in English since 1670–80 (''[[Random House Webster's Unabridged Dictionary]]'', 2001, "atomism").] is a [[natural philosophy]] proposing that the physical universe is composed of fundamental indivisible components known as ''atoms''.
The concept of atomism appeared in both [[Ancient Greek philosophy|ancient Greek]] and [[Indian philosophy|ancient Indian]] philosophical traditions. Atomism in multiple different forms appeared in ancient Greece.[{{Cite news |title=Atomism - Democritus, Epicurus, Lucretius {{!}} Britannica |url=https://www.britannica.com/topic/atomism/History-and-major-representatives-of-the-various-atomisms |archive-url=https://web.archive.org/web/20250615044100/https://www.britannica.com/topic/atomism/History-and-major-representatives-of-the-various-atomisms |archive-date=2025-06-15 |access-date=2026-02-02 |work=Encyclopedia Britannica |language=en}}] [[Leucippus]] is the earliest figure whose commitment to Greek atomism is well attested and is usually credited with inventing Greek atomism.[[[Aristotle]], ''Metaphysics'' I, 4, 985b 10–15.][[[Will Durant]] (1935), ''Our Oriental Heritage'':
{{blockquote|"Two systems of [[Hindu]] thought propound [[physics|physical]] theories suggestively similar to those of [[Ancient Greece|Greece]]. [[Kanada (philosopher)|Kanada]], founder of the [[Vaisheshika]] philosophy, held that the world was composed of atoms as many in kind as the various elements. The [[Jainism|Jains]] more nearly approximated to [[Democritus]] by teaching that all atoms were of the same kind, producing different effects by diverse modes of combinations. Kanada believed light and heat to be varieties of the same substance; [[Udayana]] taught that all heat comes from the sun; and [[Vācaspati Miśra|Vachaspati]], like [[Isaac Newton|Newton]], interpreted light as composed of minute particles emitted by substances and striking the eye."}}
] [[India]]n [[Buddhist]]s, such as [[Dharmakirti]] ({{floruit}} {{circa}} 6th or 7th century) and others, developed distinctive theories of atomism, for example, involving momentary (instantaneous) atoms ([[Kalapa (atomism)|''kalapa'']]s) that flash in and out of existence.
The particles of [[chemical matter]] for which [[chemist]]s and other natural philosophers of the early 19th century found experimental evidence were thought to be indivisible, and therefore were given by [[John Dalton]] the name "atom", long used by the atomist philosophy. Although the connection to historical atomism is at best tenuous, [[elementary particle]]s have become a modern analogue of philosophical atoms.
== Reductionism ==
Philosophical atomism is a [[reductionism|reductive]] argument, proposing not only that everything is composed of atoms and void, but that nothing they compose really exists: the only things that really exist are atoms ricocheting off each other [[mechanism (philosophy)|mechanistically]] in an otherwise empty [[Void (philosophy)|void]]. One proponent of this theory was the Greek philosopher [[Democritus]].[{{Cite book |last=Bakewell |first=C. M. (Ed.). |url=https://books.google.com/books?id=uPcPAAAAYAAJ |title=Source Book in Ancient Philosophy |publisher=Charles Scribner's sons |year=1907 |pages=60}}]
{{Blockquote|text=By convention sweet is sweet, by convention bitter is bitter, by convention hot is hot, by convention cold is cold, by convention color is color. But in reality there are atoms and the void.}}
Atomism stands in contrast to a [[substance theory]] wherein a prime material continuum remains qualitatively invariant under division (for example, the ratio of the four [[classical element]]s would be the same in any portion of a homogeneous material).
== Antiquity ==
=== Greek atomism ===
==== Democritus ====
[[File:Bust of Democritus.jpg|thumb|upright|[[Democritus]] ]]
In the 5th century BC, [[Leucippus]] and his pupil [[Democritus]] proposed that all matter was composed of small indivisible particles which they called "atoms".[''The atomists, Leucippus and Democritus: fragments, a text and translation with a commentary'' by C.C.W. Taylor, University of Toronto Press Incorporated, 1999, {{ISBN|0-8020-4390-9}}, pp. 157-158.][{{cite book|last1= Pullman|first1= Bernard|title= The Atom in the History of Human Thought|date= 1998|publisher= Oxford University Press|location= Oxford, England|isbn= 978-0-19-515040-7 |pages= 31–33|url= https://books.google.com/books?id=IQs5hur-BpgC&pg=PA56 }}][{{cite book|editor1-last= Cohen|editor1-first= Henri|editor2-last= Lefebvre |editor2-first= Claire|title=Handbook of Categorization in Cognitive Science|year=2017|publisher=Elsevier|location=Amsterdam, the Netherlands|isbn=978-0-08-101107-2|page= 427|edition= Second |url=https://books.google.com/books?id=zIrCDQAAQBAJ&pg=PA427}}][{{cite book|last=Kenny|first=Anthony|author-link=Anthony Kenny|year=2004|title=Ancient Philosophy|url=https://books.google.com/books?id=cpYUDAAAQBAJ&q=Democritus|series=A New History of Western Philosophy|volume= 1|location= Oxford, England|publisher= Oxford University Press|isbn= 0-19-875273-3|pages= 26–28}}] Nothing whatsoever is known about Leucippus except that he was the teacher of Democritus.[{{cite book|author= [[Frederic Harrison]]|url= https://archive.org/details/newcalendargrea03harrgoog/page/n118/mode/2up|title= The new calendar of great men: biographies of the 558 worthies of all ages|year= 1982|location= London and New York|publisher= Mac Millan & Co|page= 90|archive-url= https://archive.today/20210611170127/http://archive.org/stream/newcalendargrea03harrgoog/newcalendargrea03harrgoog_djvu.txt|archive-date= June 11, 2021|url-status= live|access-date= June 11, 2021}}]
The views of Democritus began as a response to the work of [[Parmenides]] who had given logical arguments against the existence of change, arguing that change is a illusion.[[[#refMelsen1952|Melsen (1952)]]] Democritus rejected Parmenides' belief that change is an illusion. He believed change was real, and if it was not then at least the illusion had to be explained. He thus supported the concept of void, and stated that the universe is made up of many entities that move around in the void.
([[:image:tetrahedron.gif|Animation]])
|[[File:tetrahedron.svg|50px|Tetrahedron]]
|4
|24
|-
|'''Air'''
|[[Octahedron]]
([[:image:octahedron.gif|Animation]])
|[[File:octahedron.svg|50px|Octahedron]]
|8
|48
|-
|'''Water'''
|[[Icosahedron]]
([[:image:icosahedron.gif|Animation]])
| [[File:icosahedron.svg|50px|Icosahedron]]
|20
|120
|-
|'''Earth'''
|[[Cube (geometry)|Cube]]
([[:image:hexahedron.gif|Animation]])
|[[File:hexahedron.svg|50px|Hexahedron (cube)]]
|6
|24
|-
|colspan=5|'''''Geometrical simple bodies according to Plato'''''
|}
Plato postulated the geometric structure of the simple bodies of the four elements as summarized in the adjacent table. The cube, with its flat base and stability, was assigned to earth; the tetrahedron was assigned to fire because its penetrating points and sharp edges made it mobile. The points and edges of the octahedron and icosahedron were blunter and so these less mobile bodies were assigned to air and water. Since the simple bodies could be decomposed into triangles, and the triangles reassembled into atoms of different elements, Plato's model offered a plausible account of changes among the primary substances.[Lloyd 1970, [https://archive.org/details/earlygreekscienc00gerl/page/74 p74–77]][{{cite book |last=Cornford |first=Francis Macdonald |url= https://archive.org/details/platoscosmologyt00plat |title=Plato's Cosmology: The ''Timaeus'' of Plato |publisher= Liberal Arts Press |year=1957 |isbn=978-0-87220-386-0 |location=New York |pages=[https://archive.org/details/platoscosmologyt00plat/page/210 210–239] |author-link=F. M. Cornford |url-access= registration}}]
==== Rejection in Aristotelianism ====
Sometime before 330 BC [[Aristotle]] asserted that the elements of fire, air, earth, and water were not made of atoms, but were continuous. Aristotle considered the existence of a void, which was required by atomic theories, to violate physical principles. Change took place not by the rearrangement of atoms to make new structures, but by transformation of matter from what it was in [[Potentiality and actuality |potential to a new actuality]]. A piece of wet clay, when acted upon by a potter, takes on its potential to be an actual drinking mug.{{cn|date=July 2026}} Aristotle may have appeared to be rejecting atomism, but in ancient Greece the atomic theories of Democritus remained "pure speculations, incapable of being put to any experimental test". On the other hand, Aristotle's qualitative model provided hypotheses which could be tested.[Lloyd 1968, [https://archive.org/details/aristotlegrowths0000lloy/page/165 p.165]][Lloyd 1970, [[iarchive:earlygreekscienc00gerl/page/108|p108–109]], [https://books.google.com/books?id=Mym7xTLfNfIC&dq=%22talk+of+the+Greeks+failing+to+use+the+experimental+method,+since+it+was+either+impracticable+or+quite+impossible+to+devise+experiments+that+would+resolve+the+issues+in+question.%22&pg=PT144]
"...it hardly makes sense to talk of the Greeks failing to use the experimental method, since it was either impracticable or quite impossible to devise experiments that would resolve the issues in question."]
Aristotle theorized ''[[minima naturalia]]'' as the smallest parts into which a homogeneous natural substance (e.g., flesh, bone, or wood) could be divided and still retain its essential character. Unlike the atomism of Democritus, these Aristotelian "natural minima" were not conceptualized as physically indivisible.{{cn|date=July 2026}}
Instead, Aristotle's concept was rooted in his [[Hylomorphism |hylomorphic]] worldview, which held that every physical thing is a compound of matter (Greek ''hyle'') and of an immaterial [[substantial form]] (Greek ''morphe'') that imparts its essential nature and structure. To use an analogy we could pose a rubber ball: we could imagine the rubber to be the matter that gives the ball the ability to take on another form, and the spherical shape to be the form that gives it its identity of "ball". Using this analogy, though, we should keep in mind that in fact rubber itself would already be considered a composite of form and matter, as it has identity and determinacy to a certain extent, pure or primary matter is completely unformed, unintelligible and with infinite potential to undergo change.{{cn|date=July 2026}}
Aristotle's intuition was that there is some smallest size beyond which matter could no longer be structured as flesh, or bone, or wood, or some other such organic substance that for Aristotle (living before the invention of the microscope) could be considered homogeneous. For instance, if flesh were divided beyond its natural minimum, what would be left might be a large amount of the element water, and smaller amounts of the other elements. But whatever water or other elements were left, they would no longer have the "nature" of flesh: in hylomorphic terms, they would no longer be matter structured by the form of flesh; instead the remaining water, e.g., would be matter structured by the form of water, not by the form of flesh.{{cn|date=July 2026}}
==== Epicurus ====
[[File:Epikouros Met 11.90.jpg|thumb|225x225px|Epicurus]]
[[Epicurus]] (341–270 BCE) studied atomism with [[Nausiphanes]] who had been a student of Democritus. Although Epicurus was certain of the existence of atoms and the void, he was less sure we could adequately explain specific natural phenomena such as earthquakes, lightning, comets, or the phases of the Moon.[Lloyd 1973, p25–6.] Few of Epicurus' writings survive, and those that do reflect his interest in applying Democritus' theories to assist people in taking [[Responsibility (disambiguation)|responsibility]] for themselves and for their own happiness—since he held there are no gods around that can help them. (Epicurus regarded the role of gods as exemplifying moral ideals.)
=== Indian atomism {{anchor|India}} ===
Preliminary instances of atomism are found in the works of [[Vedic]] sage [[Aruni]], who lived in the 8th century BCE,{{dubious|date=April 2023}} especially his proposition that "particles too small to be seen mass together into the substances and objects of experience" known as ''kaṇa''.[{{Cite book |last=Thomas|first=McEvilley|title=The shape of ancient thought : comparative studies in Greek and Indian philosophies|date=2002|publisher=Allworth Press|isbn=1581152035|location=New York|oclc=48013687}}] Although ''kana'' refers to "particles" not atoms ([[paramanu]]). Some scholars such as [[Hermann Jacobi]] and [[Randall Collins]] have compared Aruni to [[Thales of Miletus]] in their scientific methodology, calling them both as "primitive physicists" or "proto-materialist thinkers".[{{Cite book |title=Marxism : with and beyond Marx|date=2014|isbn=978-1-317-56176-7|editor1=Amiya Kumar Bagchi|location=London|oclc=910847914|editor2=Amita Chatterjee}}] Later, the [[Charvaka]],[{{cite book |last=Gangopadhyaya|first=Mrinalkanti|title=Indian Atomism: History and Sources|publisher=Humanities Press|year=1981|isbn=978-0-391-02177-8|location=Atlantic Highlands, New Jersey|oclc=10916778}}
][{{cite book |last=Iannone|first=A. Pablo|url=https://books.google.com/books?id=ISBN0415179955&pg=PA83|title=Dictionary of World Philosophy|publisher=Routledge|year=2001|isbn=978-0-415-17995-9|pages=83,356|oclc=44541769}}{{Dead link|date=September 2023|bot=InternetArchiveBot|fix-attempted=yes}}] and [[Ajivika]] schools of atomism originated as early as the 7th century BCE.[{{harv|Radhakrishnan|Moore|1957|pp=227–249}}][John M. Koller (1977), [https://www.jstor.org/stable/1397613 Skepticism in Early Indian Thought], ''Philosophy East and West'', 27(2): 155-164][Dale Riepe (1996), ''Naturalistic Tradition in Indian Thought'', Motilal Banarsidass, {{ISBN|978-8120812932}}, pages 53-58] [[Ramkrishna Bhattacharya|Bhattacharya]] posits that Charvaka may have been one of several atheistic, materialist schools that existed in ancient India.[Ramkrishna Bhattacharya (2013), The base text and its commentaries: Problem of representing and understanding the Charvaka / Lokayata, Argument: Biannual Philosophical Journal, Issue 1, Volume 3, pages 133-150][Thomas McEvilley, ''The Shape of Ancient Thought: Comparative Studies in Greek and Indian Philosophies'', Allwarth Press, 2002, pp.317–321, {{ISBN|1-58115-203-5}}.]
Kaṇāda, the founder of the Vaiśeṣika school of Indian philosophy, described atoms (paramāṇu) as eternal, indivisible, and imperceptible entities that combine to form all material substances. He proposed four classes of [[atoms]] (earth, water, light, and air).[[https://archive.org/stream/thevaiasesikasut00kanauoft#page/n7/mode/2up The ''Vaisheshika sutras'' of Kanada], 2nd Edition, Translator: Nandalal Sinha (1923); Editor: BD Basu; Note: this is the translation of non-critical edition of the manuscript][{{cite book|author1=Purusottama Bilimoria|author2=Joseph Prabhu|author3=Renuka M. Sharma|title=Indian Ethics: Classical traditions and contemporary challenges|url=https://books.google.com/books?id=g78Cw4xQmsMC |year=2007|publisher=Ashgate |isbn=978-0-7546-3301-3|page=76}}] Kaṇāda's conception of the [[atom]] was likely independent from the similar concept among the ancient Greeks, because of the differences between the theories.[ For example, Kaṇāda suggested that atoms as building blocks differ both qualitatively and quantitatively, while Greeks suggested that atoms differed only quantitatively but not qualitatively,][{{cite book|author=Edward Craig|title=Routledge Encyclopedia of Philosophy: Index|url=https://books.google.com/books?id=8FWa85vgoTQC |year=1998|publisher=Routledge |isbn=978-0-415-18715-2|pages=198–199}}] and Kaṇāda claimed that the combination of three double atoms would be visible, an idea with no parallel in the Greek models.[{{cite book
| last = Ray
| first = Praphulla Chandra
| title = A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D.
| volume = 1
| year = 1902
| publisher = Bengal Chemical & Pharmaceutical Works
| location = Calcutta
| url = https://archive.org/details/in.ernet.dli.2015.39319/page/n165/mode/2up?q=Ka%5Eada
| access-date = 2026-07-06
}}]{{rp|18}}
The [[Nyaya]]–[[Vaisesika]] school developed theories on how ''kaṇa''s combined into more complex objects.[Richard King, Indian philosophy: an introduction to Hindu and Buddhist thought, Edinburgh University Press, 1999, {{ISBN|0-7486-0954-7}}, pp.105-107.]; scholars{{who|date=March 2018}} date the Nyaya and Vaisesika texts from the 9th to 4th centuries BCE. Vaisesika atomists posited the four elemental atom types, but in Vaisesika physics atoms had 25 different possible qualities, divided between general [[intensive and extensive properties|extensive]] properties and specific (intensive) properties. The Nyaya–Vaisesika atomists had elaborate theories of how atoms combine. In Vaisesika atomism, atoms first combine into {{IAST |tryaṇuka}}s (triads) and [[Dvyanuka|Dvyaṇuka]] (dyad) before they aggregate into bodies of a kind that can be perceived.[{{cite encyclopedia |last=Berryman|first=Sylvia|title=Ancient Atomism|date=2022|url=https://plato.stanford.edu/archives/win2022/entries/atomism-ancient/|encyclopedia=[[Stanford Encyclopedia of Philosophy]]|editor-last=Zalta|editor-first=Edward N.|access-date=2023-10-06|edition=Winter 2022|publisher=Metaphysics Research Lab, [[Stanford University]]|editor2-last=Nodelman|editor2-first=Uri|editor-link=Edward N. Zalta}}]
Several of these doctrines of atomism are, in some respects, "suggestively similar" to that of Democritus.[[[Will_Durant]] wrote in ''Our Oriental Heritage'' (2011): "Two systems of Indian thought propound physical theories suggestively similar to those of Greece. [[Kanada (philosopher)|Kanada]], founder of the [[Vaisheshika]] philosophy, held that the world was composed of atoms as many in kind as the various elements more nearly approximated to [[Democritus]] by teaching that all atoms were of the same kind, producing different effects by diverse modes of combinations. The Vaisheshika believed [[Light]] and [[Heat]] to be varieties of the same substance; [[Udayana]] taught that all heat comes from the sun; and [[Vācaspati Miśra|Vachaspati]], like Newton, interpreted light as composed of minute particles emitted by substances and striking the eye."{{page needed|date=March 2018}}] McEvilley (2002) assumes that such similarities are due to extensive cultural contact and diffusion, probably in both directions.[Jeremy D. Popkin (ed.), ''The Legacies of Richard Popkin'' (2008), [https://books.google.com/books?id=gJZtBiQU6ekC&pg=PA53 p.53]]
=== Late Roman Republic ===
==== Lucretius revives Epicurus ====
[[File:Lucretius pointing to the casus.jpg|thumb|[[Lucretius]]]]
Epicurus' ideas re-appear in the works of his [[Roman Republic|Roman]] follower [[Lucretius]] ({{circa}} 99 BC – {{circa}} 55 BC), who wrote ''[[On the Nature of Things]]''. This [[Classical Latin]] scientific work in poetic form illustrates several segments of Epicurean theory on how the universe came into its current stage; it shows that the phenomena we perceive are actually composite forms. The atoms and the void are eternal and in constant motion. Atomic collisions create objects, which are still composed of the same eternal atoms whose motion for a while is incorporated into the created entity. Lucretius also explains human sensations and meteorological phenomena in terms of atomic motion.
===== "Atoms" and "vacuum" vs. religion =====
In his epic poem ''[[On the Nature of Things]],'' Lucretius depicts Epicurus as the hero who crushed the monster [[Religion]] through educating the people in what was possible in atoms and what was ''not'' possible in atoms. However,{{Non sequitur|reason=not clearly contradictory, see talk page section 'Strange assertion of contradiction'|date=May 2024}} Epicurus expressed a non-aggressive attitude characterized by his statement:[{{cite web|archive-url=https://web.archive.org/web/20070407084128/http://www.epicurus.net/en/principal.html |title=Principal Doctrines: Epicurus - Quotation #39|url = http://www.epicurus.net/en/principal.html|archive-date = 7 April 2007|url-status = live}}]
{{Blockquote|text=The man who best knows how to meet external threats makes into one family all the creatures he can; and those he can not, he at any rate does not treat as aliens; and where he finds even this impossible, he avoids all dealings, and, so far as is advantageous, excludes them from his life.}}
However, according to science historian Charles Coulston Gillispie:
{{Blockquote|text=Encased in the Epicurean philosophy, the atomic doctrine could never be welcome to moral authority. ... Epicurean gods neither created the world nor paid it ... attention. "Nature," says Lucretius, "is free and uncontrolled by proud masters and runs the universe by herself without the aid of gods." Only the atomists among ... Greek science ... was the one view of nature quite incompatible with theology. Like a pair of eighteenth-century philosophers, Epicurus and Lucretius introduced atomism as a vehicle of enlightenment. They meant to refute the pretensions of religion ... and release men from superstition and the undignified fear of capricious gods. Consequently, a hint of Epicureanism came to seem the mark of the beast in Christian Europe. No thinker, unless it is Machiavelli, has been more maligned by misrepresentation.[{{Cite book |last=Gillispie |first=C. C. |url=https://archive.org/details/edgeofobjectivit00char |title=The Edge of Objectivity: An Essay in the History of Scientific Ideas |publisher=Princeton University Press |year=1960 |pages=97–98 |author-link=Charles Coulston Gillispie}}]}}The possibility of a vacuum was accepted—or rejected—together with atoms and atomism, for the vacuum was part of that same theory.
{{Blockquote|text=Democritus and Lucretius denied the impossibility of a vacuum, being of the opinion that there must be a vacuum between the discrete particles (atoms) of which, they thought, all matter is composed. In general, however, the belief that a vacuum is impossible was almost universally held until the end of the sixteenth century.[{{Cite book |last=Middleton |first=W. E. Knowles. |url=http://archive.org/details/historyofbaromet00midd |title=The history of the barometer |date=1964 |publisher=Baltimore, Johns Hopkins Press |page=4}}] ... The time was certainly ripe for the revival of the belief in the possibility of a vacuum, but to the clerics the very name of the vacuum was anathema, being associated with the atomistic theories of Epicurus and Lucretius, which were felt to be heretical.[{{Cite book |last=Middleton |first=W. E. Knowles. |url=http://archive.org/details/historyofbaromet00midd |title=The history of the barometer |date=1964 |publisher=Baltimore, Johns Hopkins Press |page=5}}]}}
=== Roman Empire ===
==== Galen ====
[[File:Galenus (cropped)3.jpg|thumb|185x185px|[[Galen]]]]
While Aristotelian philosophy eclipsed the importance of the atomists in late Roman and medieval Europe, their work was still preserved and exposited through commentaries on the works of Aristotle. In the 2nd century, [[Galen]] (AD 129–216) presented extensive discussions of the Greek atomists, especially Epicurus, in his Aristotle commentaries.
== Middle Ages ==
=== Medieval Hinduism ===
[[Ājīvika|Ajivika]] is a "[[Āstika and nāstika|Nastika]]" school of thought whose metaphysics included a theory of atoms or atomism which was later adapted in the [[Vaiśeṣika]] school, which postulated that all objects in the physical universe are reducible to ''paramāṇu'' ([[atom]]s), and one's experiences are derived from the interplay of substance (a function of atoms, their number and their spatial arrangements), quality, activity, commonness, particularity and inherence.[Oliver Leaman, ''Key Concepts in Eastern Philosophy.'' Routledge, {{ISBN|978-0415173629}}, 1999, page 269.] Everything was composed of atoms, qualities emerged from aggregates of atoms, but the aggregation and nature of these atoms was predetermined by cosmic forces.[{{cite book |last=Basham |first=A.L. |title=History and Doctrines of the Ājīvikas | year=1951 |edition=2nd |publisher=Moltilal Banarsidass (Reprint: 2002) |location=Delhi, India | url = https://books.google.com/books?id=BiGQzc5lRGYC |isbn= 81-208-1204-2 |pages=262–270}}] [[Kanada (philosopher)|The school founder's traditional name ''Kanada'']] means 'atom eater',[{{cite book|title=Perspectives of Reality: An Introduction to the Philosophy of Hinduism|publisher=Sussex Academic Press|year=2002|isbn=978-1-898723-93-6|author=Jeaneane D. Fowler|page=99}}] and he is known for developing the foundations of an atomistic approach to physics and philosophy in the Sanskrit text ''[[Vaiśeṣika Sūtra]]''.[[https://archive.org/stream/thevaiasesikasut00kanauoft/thevaiasesikasut00kanauoft_djvu.txt "The Vaisesika sutras of Kanada. Translated by Nandalal Sinha"] Full Text at archive.org] His text is also known as ''Kanada Sutras'', or Aphorisms of Kanada.[{{cite book|last=Riepe|first=Dale Maurice |title=Naturalistic Tradition in Indian Thought|year=1961 |publisher=Motilal Banarsidass (Reprint 1996)|isbn=978-81-208-1293-2|pages=227–229}}][Kak, S. 'Matter and Mind: The Vaisheshika Sutra of Kanada' (2016), Mount Meru Publishing, Mississauga, Ontario, {{ISBN|978-1-988207-13-1}}.]
=== Medieval Buddhism ===
Medieval [[Buddhist atomism]], flourishing around the 7th century, was very different from the atomist doctrines taught in early Buddhism. Medieval Buddhist philosophers [[Dharmakirti]] and [[Dignāga]] considered atoms to be point-sized, durationless, and made of energy. In discussing the two systems, [[Fyodor Shcherbatskoy]] (1930) stresses their commonality, the postulate of "absolute qualities" (''guna-dharma'') underlying all empirical phenomena.["The Buddhists denied the existence of substantial matter altogether. Movement consists for them of moments, it is a staccato movement, momentary flashes of a stream of energy... "Everything is evanescent," ... says the Buddhist, because there is no stuff ... Both systems [Sānkhya and later Indian Buddhism] share in common a tendency to push the analysis of Existence up to its minutest, last elements which are imagined as absolute qualities, or things possessing only one unique quality. They are called "qualities" (guna-dharma) in both systems in the sense of absolute qualities, a kind of atomic, or intra-atomic, energies of which the empirical things are composed. Both systems, therefore, agree in denying the objective reality of the categories of Substance and Quality, ... and of the relation of Inference uniting them. There is in Sānkhya philosophy no separate existence of qualities. What we call quality is but a particular manifestation of a subtle entity. To every new unit of quality corresponds a subtle quantum of matter which is called guna "quality", but represents a subtle substantive entity. The same applies to early Buddhism where all qualities are substantive ... or, more precisely, dynamic entities, although they are also called dharmas ("qualities")."
Stcherbatsky (1962 [1930]). Vol. 1. p. 19.]
Still later, the [[Abhidhammattha-sangaha]], a text dated to the 11th or 12th century, postulates the existence of ''[[rupa-kalapa]]'', imagined as the smallest units of the physical world, of varying [[Mahābhūta#Buddhism|elementary]] composition.[[https://www.britannica.com/EBchecked/topic/1245/Abhidhammattha-sangaha Abhidhammattha-sangaha], Britannica Online (1998, 2005).] Invisible under normal circumstances, the ''rupa-kalapa'' are said to become visible as a result of meditative [[samadhi]].[Shankman, Richard (2008), The Experience of Samadhi: An In-depth Exploration of Buddhist Meditation, Shambhala, p. 178]
=== Medieval Islam ===
{{See also|Early Islamic philosophy#Atomism|l1=Early Islamic philosophy: Atomism|Alchemy and chemistry in medieval Islam}}
Atomistic philosophies are found very early in [[Islamic philosophy]] and were influenced originally by earlier Greek and, to some extent, Indian philosophy.[{{cite book|last=Saeed|first=Abdullah|title=Islamic Thought: An Introduction|year=2006|publisher=Routledge|isbn=978-0415364096|page=95}}][{{cite book|title=Introduction to Islamic Civilization|year=1976|publisher=Cambridge University Press|page=[https://archive.org/details/introductiontois00savo_0/page/49 49]|chapter-url=https://archive.org/details/introductiontois00savo_0|chapter-url-access=registration|quote=Islamic atomism indian greek.|author=Michael Marmura|editor=R. M. Savory|chapter=God and his creation:Two medieval Islamic views}}][{{cite book |title=Alberuni's India [The Indika of Alberuni] |author=Alberuni, Abu Al-Rahain Muhammad Ibn Ahmad |editor=Sachau, Edward C. (and trans.) |publisher=Scholar's Choice [Kegan Paul, Trench, Trübner and Co.] |date=2015 |edition=facsimile reprint |orig-year=1910 |page=xxxiii |isbn=978-1-297-45719-7 |url=https://www.infinityfoundation.com/mandala/images/alberuni.pdf}}] Islamic speculative theology in general approached issues in physics from an atomistic framework.[{{cite book|title=Arabic and Islamic Natural Philosophy and Natural Science|date=2022 |url=https://plato.stanford.edu/entries/arabic-islamic-natural/|publisher=Stanford Encyclopedia of Philosophy}}]
==== Mu'tazilite atomism ====
Atomism in [[Mu'tazilism]] as an early Islamic theology is a cosmological concept that emphasizes that the universe consists of discrete (juz’ lā yatajazzā) or undivided parts created by God. This concept is also the basis for Mu'tazila's rejection of [[determinism]]. With an atomized nature, humans are considered capable of creating actions independently (mubasharah), so they deserve rewards or punishments according to their actions. This is in line with the principle that good and bad are rational and inherent in the essence of the action itself, not just the result of God's decision. The Mu'tazilah theologians and philosophers who are famous for their atomism concepts are [[Abu al-Hudhayl al-'Allaf|Abu al-Hudhayl Al-'Allaf]] and [[Al-Jubba'i]]. While there are also Mu'tazilah theologians who are skeptical of atomism such as [[Ibrahim al-Nazzam]].[{{Cite journal |last=Karadaş |first=Cağfer |date=2018-12-31 |title=The New Approach to The Source Of Kalām Atomism |url=https://zenodo.org/records/3354384 |journal=DergiPark |doi=10.5281/zenodo.3354384}}][{{Cite journal |last=Sabra |first=A. I. |date=2009 |title=The Simple Ontology of Kalām Atomism: An Outline |url=https://www.jstor.org/stable/20617778 |journal=Early Science and Medicine |volume=14 |issue=1/3 |pages=68–78 |jstor=20617778 |issn=1383-7427}}][{{Cite web |title=A History of Muslim Philosophy |url=https://www.muslimphilosophy.com/hmp/13.htm |access-date=2025-04-14 |website=www.muslimphilosophy.com}}]
==== Al-Ghazali and Asharite atomism ====
[[File:Al-Ghazālī, Sayr mulhimah min al-Sharq wa-al-Gharb.png|thumb|200x200px|[[Al-Ghazali]] ]]
The most successful form of Islamic atomism was in the [[Asharite]] school of [[Islamic theology]], most notably in the work of the theologian [[al-Ghazali]] (1058–1111). In Asharite atomism, atoms are the only perpetual, material things in existence, and all else in the world is "accidental" meaning something that lasts for only an instant. Nothing accidental can be the cause of anything else, except perception, as it exists for a moment. Contingent events are not subject to natural physical causes, but are the direct result of God's constant intervention, without which nothing could happen. Thus nature is completely dependent on God, which meshes with other Asharite Islamic ideas on causation, or the lack thereof.[{{harvtxt|Gardet|2001}}] Al-Ghazali also used the theory to support his theory of [[occasionalism]]. In a sense, the Asharite theory of atomism has far more in common with Indian atomism than it does with Greek atomism.[{{Cite book|title=Studies in Arabic versions of Greek texts and in mediaeval science|volume=2|author=Shlomo Pines|publisher=[[Brill Publishers]]|year=1986|isbn=978-965-223-626-5|pages=355–6|author-link=Shlomo Pines}}]
==== Averroes rejects atomism ====
Other traditions in Islam rejected the atomism of the Asharites and expounded on many Greek texts, especially those of Aristotle. An active school of philosophers in Al-Andalus, including the noted commentator [[Averroes]] (1126–1198 CE) explicitly rejected the thought of al-Ghazali and turned to an extensive evaluation of the thought of Aristotle. Averroes commented in detail on most of the works of Aristotle and his commentaries became [[Averroism|very influential]] in Jewish and Christian scholastic thought.
=== Medieval Christendom ===
According to historian of atomism Joshua Gregory, no serious work was done with atomism from the time of Galen until [[Isaac Beeckman]], [[Pierre Gassendi|Gassendi]] and [[Descartes]] resurrected it in the 17th century; "the gap between these two 'modern naturalists' and the ancient Atomists marked "the exile of the atom" and "it is universally admitted that the Middle Ages had abandoned Atomism, and virtually lost it."
==== Scholasticism ====
Although the ancient atomists' works were unavailable, [[Scholasticism|scholastic]] thinkers gradually became aware of Aristotle's critiques of atomism as [[Averroes]]'s commentaries were translated into [[Latin]]. Although the atomism of Epicurus had fallen out of favor in the centuries of [[Scholasticism]], the ''[[minima naturalia]]'' of [[Aristotelianism]] received extensive consideration. Speculation on ''minima naturalia'' provided philosophical background for the mechanistic philosophy of early modern thinkers such as Descartes, and for the alchemical works of [[Pseudo-Geber|Geber]] and [[Daniel Sennert]], who in turn influenced the [[Corpuscularianism|corpuscularian]] alchemist [[Robert Boyle]], one of the founders of modern chemistry.[{{cite book|author=John Emery Murdoch|author2=Christoph Herbert Lüthy |author3=William Royall Newman |title=Late Medieval and Early Modern Corpuscular Matter Theories|chapter-url=https://books.google.com/books?id=wc97ODIpuH8C&pg=PA101|date=1 January 2001|publisher=BRILL|isbn=978-90-04-11516-3|pages=91–133|chapter=The Medieval and Renaissance Tradition of Minima Naturalia}}][{{cite book|author=Alan Chalmers|title=The Scientist's Atom and the Philosopher's Stone: How Science Succeeded and Philosophy Failed to Gain Knowledge of Atoms|url=https://books.google.com/books?id=qMsQyBVlkl4C&pg=PA76|date=4 June 2009|publisher=Springer|isbn=978-90-481-2362-9|pages=75–96}}]
A chief theme in late Roman and Scholastic commentary on this concept was reconciling ''minima naturalia'' with the general Aristotelian principle of [[infinite divisibility]]. Commentators like [[John Philoponus]] and [[Thomas Aquinas]] reconciled these aspects of Aristotle's thought by distinguishing between mathematical and "natural" divisibility. With few exceptions, much of the curriculum in the universities of Europe was based on such Aristotelianism for most of the Middle Ages.[Kargon 1966{{page needed|date=March 2018}}]
==== Nicholas of Autrecourt ====
[[File:Nicholas of Autrecourt.jpg|thumb|181x181px|[[Nicholas of Autrecourt]]]]
In [[medieval universities]] there were, however, expressions of atomism. For example, in the 14th century [[Nicholas of Autrecourt]] considered that matter, space, and time were all made up of indivisible atoms, points, and instants and that all generation and corruption took place by the rearrangement of material atoms. The similarities of his ideas with those of [[al-Ghazali]] suggest that Nicholas may have been familiar with Ghazali's work, perhaps through [[Averroes]]' refutation of it.[Marmura, 1973–74]
== Atomist renaissance ==
=== 17th century ===
In the 17th century, a renewed interest arose in [[Epicurean]] atomism and [[corpuscularianism]] as a hybrid or an alternative to [[Aristotelian physics]]. The main figures in the rebirth of atomism were [[Isaac Beeckman]], [[René Descartes]], [[Pierre Gassendi]], and [[Robert Boyle]], as well as other notable figures.
==== Northumberland circle ====
[[File:Portrait of Francis Bacon (cropped).jpg|thumb|197x197px|[[Francis Bacon]]]]
One of the first groups of atomists in England was a cadre of amateur scientists known as the Northumberland circle, led by [[Henry Percy, 9th Earl of Northumberland]] (1564–1632). Although they published little of account, they helped to disseminate atomistic ideas among the burgeoning scientific culture of England, and may have been particularly influential to [[Francis Bacon]], who became an atomist around 1605, though he later rejected some of the claims of atomism. Though they revived the classical form of atomism, this group was among the scientific avant-garde: the Northumberland circle contained nearly half of the confirmed Copernicans prior to 1610 (the year of Galileo's [[Sidereus Nuncius|''The Starry Messenger'']]). Other influential atomists of late 16th and early 17th centuries include [[Giordano Bruno]], [[Thomas Hobbes]] (who also changed his stance on atomism late in his career), and [[Thomas Hariot]]. A number of different atomistic theories were blossoming in France at this time, as well.[{{harvtxt|Clericuzio|2000}}]
==== Galileo Galilei ====
[[File:Portrait of Galileo Galilei.jpg|thumb|206x206px|[[Galileo Galilei]]]]
[[Galileo Galilei]] (1564–1642) was an advocate of atomism in his 1612 ''Discourse on Floating Bodies'' (Redondi 1969). In ''[[The Assayer]]'', Galileo offered a more complete physical system based on a [[Corpuscularianism|corpuscular]] theory of matter, in which all phenomena—with the exception of sound—are produced by "matter in motion".
===== Perceived vs. real properties =====
Atomism was associated by its leading proponents with the idea that some of the apparent properties of objects are artifacts of the perceiving mind, that is, "secondary" qualities as distinguished from "primary" qualities.[[http://www.vernonpratt.com/conceptualisations/d06bl2_1mechanical.htm The Mechanical Philosophy] {{webarchive|url=https://web.archive.org/web/20080611053822/http://www.vernonpratt.com/conceptualisations/d06bl2_1mechanical.htm|date=June 11, 2008}} - Early modern 'atomism' ("corpuscularianism" as it was known)] Galileo identified some basic problems with Aristotelian physics through his experiments. He utilized a theory of atomism as a partial replacement, but he was never unequivocally committed to it. For example, his experiments with falling bodies and inclined planes led him to the concepts of circular inertial motion and accelerating free-fall. The current Aristotelian theories of impetus and terrestrial motion were inadequate to explain these. While atomism did not explain the [[law of fall]] either, it was a more promising framework in which to develop an explanation because motion was conserved in ancient atomism (unlike Aristotelian physics).
==== René Descartes ====
[[File:Frans Hals - Portret van René Descartes (cropped)3.jpg|alt=Portrait of René Descartes|thumb|150x150px|[[René Descartes]]]]
[[René Descartes]]' (1596–1650) [[Mechanical explanations of gravitation#Vortex|"mechanical" philosophy]] of corpuscularism had much in common with atomism, and is considered, in some senses, to be a different version of it. Descartes thought everything physical in the universe to be made of tiny ''vortices'' of matter. Like the ancient atomists, Descartes claimed that sensations, such as taste or temperature, are caused by the shape and size of tiny pieces of matter. In ''Principles of Philosophy'' (1644) he writes: "The nature of body consists just in extension—not in weight, hardness, colour or the like."[{{Cite book |last=Descartes |first=R. |url=https://www.earlymoderntexts.com/assets/pdfs/descartes1644part2.pdf |title=Principles of Philosophy |year=2008 |editor-last=Bennett |editor-first=J. |edition= |at=Part II, § 4. |orig-date=1644}}] The main difference between atomism and Descartes' concept was the existence of the void. For him, there could be no vacuum, and all matter was constantly swirling to prevent a void as corpuscles moved through other matter. Another key distinction between Descartes' view and classical atomism is the [[Dualism (philosophy of mind)|mind/body duality]] of Descartes, which allowed for an independent realm of existence for thought, soul, and most importantly, God.
==== Pierre Gassendi ====
[[File:Pierre Gassendi (Unknown artist).jpg|thumb|169x169px|[[Pierre Gassendi]]]]
[[Pierre Gassendi]] (1592–1655) was a Catholic priest from France who was also an avid natural philosopher. Gassendi's concept of atomism was closer to classical atomism, but with no atheistic overtone. He was particularly intrigued by the Greek atomists, so he set out to "purify" atomism from its heretical and atheistic philosophical conclusions (Dijksterhius 1969). Gassendi formulated his atomistic conception of [[mechanical philosophy]] partly in response to Descartes; he particularly opposed Descartes' reductionist view that only purely mechanical explanations of physics are valid, as well as the application of geometry to the whole of physics.[
==== Johann Chrysostom Magnenus ====
[[File:Burning Incense.jpg|thumb|168x168px|Burning incense]]
[[Johann Chrysostom Magnenus]] ({{circa|1590|lk=no}} – {{circa|1679|lk=no}}) published his ''Democritus reviviscens'' in 1646. Magnenus was the first to arrive at a scientific estimate of the size of an "atom" (i.e. of what would today be called a [[molecule]]). Measuring how much [[incense]] had to be burned before it could be smelled everywhere in a large church, he calculated the number of molecules in a grain of incense to be of the order 1018, only about one order of magnitude below the actual figure.][{{cite book | doi=10.1021/bk-2013-1122.ch001 | chapter=Three Millennia of Atoms and Molecules | title=Pioneers of Quantum Chemistry | series=ACS Symposium Series | year=2013 | last1=Ruedenberg | first1=Klaus | last2=Schwarz | first2=W. H. Eugen | volume=1122 | pages=1–45 | isbn=9780841227163 }}]
=== Atomism and corpuscularianism ===
{{Main article|Corpuscularianism}}
[[File:Portret van Robert Boyle, RP-P-OB-4578 (cropped).jpg|thumb|192x192px|[[Robert Boyle]] ]]
[[Corpuscularianism]] is similar to atomism, except that where atoms were supposed to be indivisible, corpuscles could in principle be divided. In this manner, for example, it was theorized that mercury could penetrate into metals and modify their inner structure, a step on the way towards transmutative production of gold. Corpuscularianism was associated by its leading proponents with the idea that some of the properties that objects appear to have are artifacts of the perceiving mind: 'secondary' qualities as distinguished from 'primary' qualities.[[http://www.vernonpratt.com/conceptualisations/d06bl2_1mechanical.htm The Mechanical Philosophy] {{webarchive |url=https://web.archive.org/web/20080611053822/http://www.vernonpratt.com/conceptualisations/d06bl2_1mechanical.htm |date=June 11, 2008 }} - Early modern 'atomism' ("corpuscularianism" as it was known)] Not all corpuscularianism made use of the primary-secondary quality distinction, however. An influential tradition in medieval and early modern alchemy argued that chemical analysis revealed the existence of robust corpuscles that retained their identity in chemical compounds (to use the modern term). [[William R. Newman]] has dubbed this approach to matter theory "chymical atomism," and has argued for its significance to both the mechanical philosophy and to the chemical atomism that emerged in the early 19th century.[William R. Newman, “The Significance of ‘Chymical Atomism’,” in Edith Sylla and W. R. Newman, eds., ''Evidence and Interpretation: Studies on Early Science and Medicine in Honor of John E. Murdoch'' (Leiden: Brill, 2009), pp. 248-264][Newman, ''Atoms and Alchemy: Chymistry and the Experimental Origins of the Scientific Revolution'' (Chicago: University of Chicago Press, 2006)]
[[File:Isaac Newton by James Thronill, after Sir Godfrey Kneller.jpg|thumb|187x187px|[[Isaac Newton]]]]
Corpuscularianism stayed a dominant theory over the next several hundred years and retained its links with [[alchemy]] in the work of scientists such as [[Robert Boyle]] (1627–1692) and [[Isaac Newton]] in the 17th century.[{{cite book|last = Levere | first = Trevor, H. | title= Transforming Matter – A History of Chemistry for Alchemy to the Buckyball|publisher=The Johns Hopkins University Press|year=2001| isbn=978-0-8018-6610-4}}][[https://www.philosophypages.com/dy/c9.htm Corpuscularianism] - Philosophical Dictionary] It was used by Newton, for instance, in his development of the [[corpuscular theory of light]]. The form that came to be accepted by most English scientists after Robert Boyle was an amalgam of the systems of Descartes and Gassendi. In ''[[The Sceptical Chymist]]'' (1661), Boyle demonstrates problems that arise from chemistry, and offers up atomism as a possible explanation. The unifying principle that would eventually lead to the acceptance of a hybrid corpuscular–atomism was [[mechanism (philosophy)|mechanical philosophy]], which became widely accepted by [[physical sciences]]. Boyle referred to indivisible particles as ''minima naturalia'' or ''prima naturalia'', and only very rarely used the term "atom".[{{cite encyclopedia |last=Chalmers |first=Alan |author-link1=Alan Chalmers |encyclopedia=[[Stanford Encyclopedia of Philosophy]] |editor-last=Zalta |editor-first=Edward N. |editor-last2=Nodelman |editor-first2=Uri |title=Atomism from the 17th to the 20th Century |url=https://plato.stanford.edu/archives/spr2026/entries/atomism-modern/ |edition=Spring 2026 |publisher=Metaphysics Research Lab, [[Stanford University]]|at=[https://plato.stanford.edu/entries/atomism-modern/#AtoMec §2.1 Atomism and the Mechanical Philosophy]|year=2026|editor-link=Edward N. Zalta}}]
==== Mikhail Lomonosov ====
[[File:Mikhail Lomonosov by L. Miropolskiy after G. C. Prenner (1787).jpg|thumb|242x242px|[[Mikhail Lomonosov]] ]]
In his 1744 paper ''Meditations on the Cause of Heat and Cold'', Russian polymath [[Mikhail Lomonosov]] specifically defined corpuscles as composite particles: "An element is part of a body which is not composed of any other smaller body ... A corpuscle is a collection of elements which constitute one small mass.."[{{Cite book |last=Lomonosov |first=Mikhail Vasil'evich |url=https://archive.org/details/mikhailvasilevic017733mbp |title=Mikhail Vasil'evich Lomonosov on the Corpuscular Theory |publisher=Harvard University Press |year=1970 |editor-last=Leicester |editor-first=Henry M. |editor-link=Henry M. Leicester |pages=56–57 |translator-last= |translator-first= |chapter=Meditations on the Cause of Heat and Cold |orig-date=1750 |chapter-url=https://archive.org/details/mikhailvasilevic017733mbp/page/n71/mode/1up}}] In a later study (1748), he uses the term "atom" instead of "element", and "particula" (particle) or "molecule" instead of "corpuscle."
== Modern atomic theory ==
{{Main article|Atomic theory}}
=== Late 18th century ===
[[File:Ruđer Bošković (Roger Boscovich).jpg|thumb|198x198px|[[Roger Joseph Boscovich|Roger Boscovich]]]]
By the late 18th century, the useful practices of engineering and technology began to influence philosophical explanations of the composition of matter. Those who speculated on the ultimate nature of matter began to verify their "thought experiments" with some repeatable [[Scientific demonstration|demonstrations]], when they could.
[[Republic of Ragusa|Ragusan]] polymath [[Roger Boscovich]] (1711–1787) provided the first general mathematical theory of atomism based on the ideas of Newton and Leibniz, but transforming them so as to provide a programme for atomic physics.[[[Lancelot Law Whyte|Whyte, Lancelot]], Essay on Atomism, 1961, p.54]
=== 19th century ===
==== John Dalton ====
[[File:John Dalton by Charles Turner (cropped).jpg|thumb|233x233px|[[John Dalton]]]]
In 1808, English physicist [[John Dalton]] (1766–1844) assimilated the known experimental work of many people to summarize the [[empirical evidence]] on the composition of matter.[{{cite book | last = Dalton | first = John | title = A new system of chemical philosophy | year = 1808 | url = https://archive.org/details/newsystemofchemi01daltuoft | access-date =8 July 2008 | isbn = 978-1-153-05671-7| publisher = London }}] He noticed that distilled water everywhere analyzed to the same elements, [[hydrogen]] and [[oxygen]]. Similarly, other purified substances decomposed to the same elements in the same proportions by weight.
:Therefore we may conclude that the ultimate particles of all homogeneous bodies are perfectly alike in weight, figure, etc. In other words, every particle of water is like every other particle of water; every particle of hydrogen is like every other particle of hydrogen, etc.
Furthermore, he concluded that there was a unique atom for each element, using [[Lavoisier]]'s definition of an element as a substance that could not be [[analysis|analyzed]] into something simpler. Thus, Dalton concluded the following.
:Chemical [[chemical analysis|analysis]] and [[Chemical synthesis|synthesis]] go no farther than to the separation of particles one from another, and to their reunion. No new creation or destruction of matter is within the reach of chemical agency. We might as well attempt to introduce a new planet into the solar system, or to annihilate one already in existence, as to create or destroy a particle of hydrogen. All the changes we can produce, consist in separating particles that are in a state of cohesion or combination, and joining those that were previously at a distance.
[[File:John Dalton; Formulae for water and ammonia. 1807 Wellcome M0004648.jpg|thumb|John Dalton's alternative formulae for water and ammonia]]
And then he proceeded to give a list of relative weights in the compositions of several common compounds, summarizing:[{{cite web|url=http://webserver.lemoyne.edu/faculty/giunta/dalton.html |title=A New System of Chemical Philosophy |access-date=2003-07-28 |url-status=dead |archive-url=https://web.archive.org/web/20030802193611/http://webserver.lemoyne.edu/faculty/giunta/dalton.html |archive-date=2003-08-02 }}]
:1st. That [[water]] is a binary compound of hydrogen and oxygen, and the relative weights of the two elementary atoms are as 1:7, nearly;
:2nd. That [[ammonia]] is a binary compound of hydrogen and azote [[nitrogen]], and the relative weights of the two atoms are as 1:5, nearly...
Dalton concluded that the fixed proportions of elements by weight suggested that the atoms of one element combined with only a limited number of atoms of the other elements to form the substances that he listed.
==== Atomic theory debate ====
[[File:Alexander William Williamson, ante 1904 - Accademia delle Scienze di Torino 0116 B.jpg|thumb|218x218px|[[Alexander William Williamson]]]]
Dalton's [[atomic theory]] remained controversial throughout the 19th century.[Brock 1967, p.1] Whilst the Law of definite proportion was accepted, the hypothesis that this was due to atoms was not so widely accepted. For example, in 1826 when [[Humphry Davy|Sir Humphry Davy]] presented Dalton the [[Royal Medal]] from the [[Royal Society]], Davy said that the theory only became useful when the atomic conjecture was ignored.[{{cite book | editor-last = Davy | editor-first = J. | title = Collected Works of Sir Humphry Davy | publisher=Bart. | page = 93 vol 8 }}] English chemist [[Sir Benjamin Collins Brodie, 2nd Baronet|Sir Benjamin Collins Brodie]] in 1866 published the first part of his Calculus of Chemical Operations[{{cite book | last = Brodie | first = Sir Benjamin Collins | title = Philosophical Transactions of the Royal Society | year=1866 | pages =781–859 vol I56 }}] as a non-atomic alternative to the atomic theory. He described atomic theory as a 'Thoroughly materialistic bit of joiners work'.[Brock 1967, p.12] English chemist [[Alexander William Williamson|Alexander Williamson]] used his Presidential Address to the London Chemical Society in 1869[Brock 1967, p.15] to defend the atomic theory against its critics and doubters. This in turn led to further meetings at which the positivists again attacked the supposition that there were atoms. The matter was finally resolved in Dalton's favour in the early 20th century with the rise of [[atomic physics]].
==== Vortex theory ====
{{main|Vortex theory of the atom}}
From the 1860s to around 1890 a theory originally proposed by [[William Thomson, 1st Baron Kelvin|William Thomson]] and expanded by and [[JJ Thomson]] viewed atoms as vortices in a pervasive continuous fluid medium. The idea was to view matter as stable rotations in the [[perfect fluid|frictionless fluid]] akin to [[smoke rings]] which were used to visually illustrate the concept.[{{rp|38}} Descartes' earlier vortex theory envisioned swirling tiny particles, but in the Thomson's model the vortices existing in a continuous medium.][{{rp|33}} The theory overlapped the rise of the theory of [[luminiferous aether]] in concept and in time frame but the two theories were not identical.][{{rp|49}} While the theory had a significant impact on mathematics, inspiring the [[theory of knots]] for example,][{{rp|46}} its own advocates eventually concluded that the vortices were not stable and furthermore the theory offered no account of phenomena such as magnetism and gravitation.][{{Cite journal |last=Kragh |first=Helge |date=2002 |title=The Vortex Atom: A Victorian Theory of Everything |url=https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1600-0498.2002.440102.x |journal=Centaurus |language=en |volume=44 |issue=1–2 |pages=32–114 |doi=10.1034/j.1600-0498.2002.440102.x |issn=1600-0498|url-access=subscription }}]{{rp|75}}
=== 20th century ===
==== Experimental verification ====
[[File:Jean Perrin.jpg|alt=Photo of Jean Perrin|thumb|206x206px|[[Jean Baptiste Perrin|Jean Perrin]]]]
[[Atomic theory|Atoms and molecules]] had long been theorized as the constituents of matter, and [[Albert Einstein]] published a [[Über die von der molekularkinetischen Theorie der Wärme geforderte Bewegung von in ruhenden Flüssigkeiten suspendierten Teilchen|paper in 1905]] that explained how the motion that Scottish botanist [[Robert Brown (botanist, born 1773)|Robert Brown]] had observed was a result of the pollen being moved by individual water molecules, making one of his first contributions to science. This explanation of [[Brownian motion]] served as convincing evidence that atoms and molecules exist, and was further verified experimentally by French physicist [[Jean Baptiste Perrin|Jean Perrin]] (1870–1942) in 1908. Perrin was awarded the [[Nobel Prize in Physics]] in 1926 "for his work on the discontinuous structure of matter". The direction of the force of atomic bombardment is constantly changing, and at different times the particle is hit more on one side than another, leading to the seemingly random nature of the motion.
== See also ==
* [[Eliminative materialism]]
* [[First principle]]
* [[History of chemistry]]
* [[Mereological nihilism]]
* [[Montonen–Olive duality#Philosophical implications]]
* [[Ontological pluralism]]
* [[Physicalism]]
* [[Prima materia]]
* [[Process philosophy]]
== References ==
=== Citations ===
{{reflist|30em}}
=== References ===
{{refbegin|30em}}
* {{cite book | editor-last = Brock | editor-first = W.H. | title = The Atomic Debates | publisher=Leicester University Press | year = 1967}}
* {{cite book|last=Clericuzio|first=Antonio|title=Elements, Principles, and Corpuscles; a study of atomism and chemistry in the seventeenth century|location=Dordrecht; Boston|publisher=Kluwer Academic Publishers|year= 2000}}
* [[F. M. Cornford|Cornford, Francis MacDonald.]] ''Plato's Cosmology: The ''Timaeus'' of Plato''. New York: Liberal Arts Press, 1957.
* [[Eduard Jan Dijksterhuis|Dijksterhuis, E.]] ''The Mechanization of the World Picture''. Trans. by C. Dikshoorn. New York: Oxford University Press, 1969. {{ISBN|0-691-02396-4}}
* Firth, Raymond. ''Religion: A Humanist Interpretation''. Routledge, 1996. {{ISBN|0-415-12897-8}}.
* {{Cite book |last=Galilei |first=G. |url=https://www.mercaba.es/renacimiento/escritos_menores_de_galileo.pdf |title=Discoveries and Opinions of Galileo |publisher=Doubleday |year=1957 |editor-last=Drake |editor-first=S. |volume= |chapter=The Assayer |orig-date=1623}}
* Gangopadhyaya, Mrinalkanti. ''Indian Atomism: history and sources''. Atlantic Highlands, New Jersey: Humanities Press, 1981. {{ISBN|0-391-02177-X}}
* {{cite book|last=Gardet|first=L.|chapter=djuz|title=Encyclopaedia of Islam CD-ROM Edition, v. 1.1|location=Leiden|publisher=Brill|date=2001}}
* {{Cite book |last=Gillispie |first=C. C. |url=https://archive.org/details/edgeofobjectivit00char |title=The Edge of Objectivity: An Essay in the History of Scientific Ideas |publisher=Princeton University Press |year=1960 |author-link=Charles Coulston Gillispie}}
* Gregory, Joshua C. ''A Short History of Atomism''. London: A. and C. Black, Ltd, 1981.
* Kargon, Robert Hugh. ''Atomism in England from Hariot to Newton''. Oxford: Clarendon Press, 1966.
* {{cite book| title = Aristotle: The Growth and Structure of his Thought| url = https://archive.org/details/aristotlegrowths0000lloy| url-access = registration| last = Lloyd| first = Geoffrey| author-link = G. E. R. Lloyd| publisher = [[Cambridge University Press]]| location = Cambridge| year = 1968| isbn = 978-0-521-09456-6}}
*{{cite book| title = Early Greek Science: Thales to Aristotle| last = Lloyd| first = Geoffrey
| publisher = [[Chatto and Windus]]; [[W. W. Norton & Company]]| location = London; New York
| year = 1970
| isbn = 978-0-393-00583-7
| url = https://archive.org/details/earlygreekscienc00gerl/page/74}}
* Lloyd, Geoffrey (1973). ''Greek Science After Aristotle''. New York: W. W. Norton, . {{ISBN|0-393-00780-4}}
* Marmura, Michael E. "Causation in Islamic Thought." ''Dictionary of the History of Ideas''. New York: Charles Scribner's Sons, 1973–74
* McEvilley, Thomas (2002). ''[[The Shape of Ancient Thought|The Shape of Ancient Thought: Comparative Studies in Greek and Indian Philosophies]]''. New York: Allworth Communications Inc. {{ISBN|1-58115-203-5}}.
*{{cite book |first=Andrew G. van|last= Melsen |translator=Henry J. Koren |year=2004 |orig-year=First published 1952 |title=From Atomos to Atom: The History of the Concept Atom |publisher=Dover Publications |isbn=0-486-49584-1 |ref=refMelsen1952}}
* {{cite book|last1=Radhakrishnan|first1=Sarvepalli |last2= Moore|first2= Charles|title=A Source Book in Indian Philosophy|date=1957|publisher=Princeton University Press|isbn=978-0-691-01958-1|url=https://archive.org/details/sourcebookinindi00radh}}
* Redondi, Pietro. ''Galileo Heretic''. Translated by Raymond Rosenthal. Princeton, NJ: Princeton University Press, 1987. {{ISBN|0-691-02426-X}}
* {{cite book | last = Riepe | first = Dale | year = 1964 | title = The Naturalistic Tradition of Indian Thought | edition = 2nd | publisher = Motilal Banarsidass | location = Delhi}}
{{refend}}
== External links ==
{{wiktionary|atomism}}
* [https://xtf.lib.virginia.edu/xtf/view?docId=DicHist/uvaBook/tei/DicHist1.xml;chunk.id=dv1-21 ''Atomism: Antiquity to the Seventeenth Century''] at the ''[[Dictionary of the History of Ideas]]''
* [https://xtf.lib.virginia.edu/xtf/view?docId=DicHist/uvaBook/tei/DicHist1.xml;chunk.id=dv1-22 ''Atomism in the Seventeenth Century''] at the ''[[Dictionary of the History of Ideas]]''
* Jonathan Schaffer, [https://web.archive.org/web/20061221163403/http://people.umass.edu/schaffer/papers/Fundamental.pdf "Is There a Fundamental Level?"] ''Nous'' 37 (2003): 498–517. By a philosopher who opposes atomism
* [https://plato.stanford.edu/entries/democritus/ Democritus] at the ''[[Stanford Encyclopedia of Philosophy]]''
* [https://plato.stanford.edu/entries/atomism-modern/ Atomism from the 17th to the 20th Century] at the ''[[Stanford Encyclopedia of Philosophy]]''
{{Greek schools of philosophy}}
{{Indian Philosophy}}
{{Authority control}}
[[Category:Atomism| ]]
[[Category:Metaphysical theories]]
[[Category:Presocratic philosophy]]