Atomism ()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 and ancient Indian philosophical traditions. Atomism in multiple different forms originated in ancient Greece. The word atom is derived from the term atomos ("uncuttable") used by the Greek philosophers Leucippus and his pupil Democritus, who developed this idea in the 5th century BC.The atomists, Leucippus and Democritus: fragments, a text and translation with a commentary by C.C.W. Taylor, University of Toronto Press Incorporated, 1999, , pp. 157-158. Leucippus, Democritus, and other ancient Greek atomists argued that nature consists of two fundamental principles: atoms and void. Clusters of different shapes, arrangements, and positions give rise to the various macroscopic substances in the world.Aristotle, Metaphysics I, 4, 985b 10–15.A similar idea was developed by Kanāda of the Vaiśeṣika school, who proposed indivisible particles (paramāṇu).Will Durant (1935), Our Oriental Heritage: Indian Buddhists, such as Dharmakirti ( 6th or 7th century) and others, developed distinctive theories of atomism, for example, involving momentary (instantaneous) atoms (kalapas) that flash in and out of existence.
The particles of chemical matter for which chemists 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 particles have become a modern analogue of philosophical atoms.
Antiquity
Greek atomism
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, , pp. 157-158. Nothing whatsoever is known about Leucippus except that he was the teacher of Democritus. Democritus, by contrast, wrote prolifically, producing over eighty known treatises, none of which have survived to the present day complete. However, a massive number of fragments and quotations of his writings have survived. These are the main source of information on his teachings about atoms. Democritus's argument for the existence of atoms hinged on the idea that it is impossible to keep dividing matter infinitely - and that matter must therefore be made up of extremely tiny particles. The atomistic theory aimed to remove the "distinction which the Eleatic school drew between the Absolute, or the only real existence, and the world of change around us."
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.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. The void is infinite and provides the space in which the atoms can pack or scatter differently. The different possible packings and scatterings within the void make up the shifting outlines and bulk of the objects that organisms feel, see, eat, hear, smell, and taste. While organisms may feel hot or cold, hot and cold actually have no real existence. They are simply sensations produced in organisms by the different packings and scatterings of the atoms in the void that compose the object that organisms sense as being "hot" or "cold". As Democritus puts it:
Democritus believed that atoms are too small for human senses to detect, that they are infinitely many, that they come in infinitely many varieties, and that they have always existed. They float in a vacuum, which Democritus called the "void", and they vary in form, order, and posture. Some atoms, he maintained, are convex, others concave, some shaped like hooks, and others like eyes. They are constantly moving and colliding into each other. Democritus wrote that atoms and void are the only things that exist and that all other things are merely said to exist by social convention. The objects humans see in everyday life are composed of many atoms united by random collisions and their forms and materials are determined by what kinds of atom make them up. Likewise, human perceptions are caused by atoms as well. Bitterness is caused by small, angular, jagged atoms passing across the tongue; whereas sweetness is caused by larger, smoother, more rounded atoms passing across the tongue.
The work of Democritus survives only in secondhand reports, some of which are unreliable or conflicting. Much of the best evidence of Democritus' theory of atomism is reported by Aristotle (384–322 BCE) in his discussions of Democritus' and Plato's contrasting views on the types of indivisibles composing the natural world.
Plato
Plato, as expressed by Timaeus, described solids as composed of indivisible triangles. Different arrangements of these triangles lead to four simple bodies of fire, air, water, and earth; rearrangements of the triangles were possible, accounting for the possible transformation of these elements. Element PolyhedronNumber of FacesNumber of TrianglesFireTetrahedron (Animation)424AirOctahedron (Animation)848WaterIcosahedron (Animation) 20120EarthCube (Animation)624Geometrical 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, p74–77
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 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. 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, p.165Lloyd 1970, p108–109, "...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. Instead, Aristotle's concept was rooted in his 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.
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.
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 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 Preliminary instances of atomism are found in the works of Vedic sage Aruni, who lived in the 8th century BCE, especially his proposition that "particles too small to be seen mass together into the substances and objects of experience" known as kaṇa. 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". Later, the Charvaka, and Ajivika schools of atomism originated as early as the 7th century BCE.John M. Koller (1977), Skepticism in Early Indian Thought, Philosophy East and West, 27(2): 155-164Dale Riepe (1996), Naturalistic Tradition in Indian Thought, Motilal Banarsidass, , pages 53-58 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 133-150Thomas McEvilley, The Shape of Ancient Thought: Comparative Studies in Greek and Indian Philosophies, Allwarth Press, 2002, pp.317–321, .