Atomism
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.
In the 5th century BC, Leucippus and his pupil Democritus proposed that all matter was composed of small indivisible particles which they called "atoms".
[10] 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 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.
Most recent students of presocratic philosophy, such as Kurt von Fritz, Walter Burkert, Gregory Vlastos, Jonathan Barnes, and Daniel W. Graham have rejected that any form of atomism can be applied to the early Pythagoreans (before Ecphantus of Syracuse).
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.
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.
[25] 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.
In ancient Indian philosophy, preliminary instances of atomism are found in the works of Vedic sage Aruni, who lived in the 8th century BCE,[dubious – discuss] especially his proposition that "particles too small to be seen mass together into the substances and objects of experience" known as kaṇa.
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".
However,[non sequitur] Epicurus expressed a non-aggressive attitude characterized by his statement:[39] 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: Encased in the Epicurean philosophy, the atomic doctrine could never be welcome to moral authority.
[44] The school founder's traditional name Kanada means 'atom eater',[45] and he is known for developing the foundations of an atomistic approach to physics and philosophy in the Sanskrit text Vaiśeṣika Sūtra.
In discussing the two systems, Fyodor Shcherbatskoy (1930) stresses their commonality, the postulate of "absolute qualities" (guna-dharma) underlying all empirical phenomena.
[49] 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 elementary composition.
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 (Gardet 2001).
Although the ancient atomists' works were unavailable, 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.
[57][58] 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.
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 The Starry Messenger).
For example, his experiments with falling bodies and inclined planes led him to the concepts of circular inertial motion and accelerating free-fall.
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.
He was particularly intrigued by the Greek atomists, so he set out to "purify" atomism from its heretical and atheistic philosophical conclusions (Dijksterhius 1969).
[65][66] 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.
[71] 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.
[75] English chemist Sir Benjamin Collins Brodie in 1866 published the first part of his Calculus of Chemical Operations[76] as a non-atomic alternative to the atomic theory.
[77] English chemist Alexander Williamson used his Presidential Address to the London Chemical Society in 1869[78] to defend the atomic theory against its critics and doubters.
This explanation of Brownian motion served as convincing evidence that atoms and molecules exist, and was further verified experimentally by French physicist Jean Perrin (1870–1942) in 1908.
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.
