▷ Atomism - PhilosophyProfessor.com

Atomism is a philosophical theory that emerged in Ancient Greece during the fifth century BC and in India around 200 BC-100 BC., according to which the universe is made up of combinations of small, indivisible particles called atoms (from the Greek ἄτομον, “uncuttable”, “indivisible”).

As a physical theory, atomism was invented by Leucippus and Democritus in the 5th century BC (although perhaps much earlier by Moses of Sidon), developed by Epicurus a century or so later, and revived in the 17th century.

In it, matter consisted of tiny indivisible, indestructible and unchanging bits of solid stuff, differing in shape and size, and jostling each other in the void to constitute the material world. They were responsible for colors, smells, tastes, and so on (the ‘secondary’ qualities; also see: effluxes), but did not themselves have them.

In the earliest phase physical divisibility may not have been distinguished from conceptual or mathematical divisibility, despite the atoms’ having shapes. The rival ‘continuous’ theory of matter, with no void, was initially held by Aristotle (384-322 BC) and the Stoics, but atomism has proved more fruitful in the development of modern physical theory, despite its enormous differences.

More generally, any theory can be called atomism which analyzes a certain set of phenomena in terms of a set of (not necessarily physical) building blocks, each having a narrowly circumscribed set of properties (for example, sensations or ideas in the case of sensationalism or associationism).

Also see: logical atomism, semantic atomism.

Table of Contents

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History

Development of the theory

In ancient beliefs, the atom was defined as the smallest element, both large and indivisible, from which all things are made. According to the mechanistic atomism of Leucippus and Democritus (5th and 4th centuries BC), atoms are indestructible material particles, devoid of qualities, which cannot be distinguished from each other except by their shape and dimension, and which, by their various combinations in a vacuum, constitute different bodies. This conception of nature is absolutely materialistic, and explains all natural phenomena in terms of the number, shape and size of atoms. It even reduces the sensory properties of things to the quantitative differences of atoms.

Atomism appears in Greek philosophy as an attempt to overcome the logical difficulties in explaining the change of things considered in the eleathic school. It affirms what it affirms and can also affirm what it denies, thus becoming more comprehensive as a theory. There is no disjunction between being and not being, but both things, only that being is not effectively such, that is, space and emptiness. This simultaneity of the opposites constitutes the source of the movement.

This atomic theory runs with such fluidity the transit of the being to things, suppresses at once so many obstacles for the mechanical and mathematical understanding of the universe, that since then it became a model for any rational investigation of nature. It is also presented as being akin to the pluralism of Anaxagoras or Empedocles (5th century BC). Anaxagoras considered that everything was made up of elementary particles called homeomers, which were conceptually different (although very similar) to the atoms of Leucippus and Democritus, while Empedocles claimed that almost everything (not the eyes, for example) is made up of the four elements, namely air, water, earth and fire.

The essence of the atomistic argument is as follows. Let us take as valid the hypothesis, “material things are divisible to infinity”. Since such a division is possible, let us imagine that we carry it out with a body; what then remains of it? Either the product of division is a number of bodies with physical magnitude, or it consists of a number of elements that have no magnitude. In the first case the residual bodies with magnitude must still be able to be divided, because the division would not have been completely carried out, which contradicts the starting point. In the second case, the original body, which has magnitude, would be composed of elements that have no magnitude, which is impossible. The sum of infinite elements that do not possess magnitude gives rise to an element without magnitude. So both possible results lead to an absurdity and therefore the hypothesis that material bodies are divisible up to infinity has to be false and therefore there must be a limit to this division, a basic unit of indivisible matter that possesses magnitude, called an atom, and from which it cannot be further divided.

In India, on the other hand, similar conclusions were reached by the Jainists Ajivika and Chárvaka and the schools of orthodox Hinduism Nyaya and vaiśeṣika.

Aristotelian criticism and further development

Aristotle accepts the atomistic idea and reconciles it with Plato’s philosophy of forms, arguing that both are right. He explained it through the first substance and the secondary categories or substances that depend on it. The first substance would be the matter of the atomists and the categories dependent on it would be the properties that define that matter which makes it what it is. All this is explained in his doctrine of the four causes.

To avoid mechanistic determinism, criticized by Aristotle, Lucretius takes the thought of Epicurus and introduces the thesis that atoms fall into the void and experience by themselves a declination that allows them to meet (theory of the clinamen). In this way he tries to impose a certain order on the original idea that things are formed by a chaotic movement of atoms.

In the Middle and Modern Ages

In the Middle Ages, despite the general opposition to atomism based on theological considerations, and above all because of the strong influence of Aristotle, this doctrine was maintained by William of Conches and Nicholas of Autrecourt. The theory gained new momentum in the 15th and 16th centuries, coinciding with the criticism of Aristotelianism, with the ideas of Nicolas de Cusa and Giordano Bruno, reaching a climax with the renewal of Gassendi, who considered atomism as the most reasonable hypothesis for the explanation of natural phenomena. At this time, the problems inherent in the atomist doctrine were debated: the logical difficulty of admitting that there is a portion of matter that cannot be divided, and the difficulties of explaining the diversity of the physical and chemical properties of bodies. It is also undeniable the influence it later acquired on the origins of scientific atomic theory, starting with the Serbian scientist Ruđer Bošković (1711-1787), who first sketched out a modern atomic theory with a Newtonian foundation that established forces of cohesion and repulsion.