atomisme

Atomisme is a philosophical and scientific doctrine that proposes matter is composed of small, indivisible units called atoms, which move through empty space or the void. According to atomism, the diversity of substances results from different kinds of atoms, their shapes, sizes, and arrangements, rather than from continuous matter.

The roots of atomism lie in ancient Greece, where thinkers such as Leucippus and his student Democritus argued that all change is the result of atoms combining, separating, or rearranging in the void. They held that atoms are eternal, indivisible, and differ in quality by virtue of their arrangement. Epicurus later refined these ideas, while Lucretius popularized them in his poem De rerum natura. Aristotle rejected atomism, proposing instead that nature operates through continuous matter endowed with form and principle of change. Atomistic ideas persisted in some later philosophical and scientific traditions, including certain Islamic scholars and Renaissance thinkers.

In modern science, atomism reemerged as a robust scientific theory. John Dalton formulated an atomic theory of matter in chemistry, asserting that elements consist of atoms and that compounds arise from combinations of atoms in fixed ratios. The discovery of subatomic particles—electrons, protons, and neutrons—and the development of quantum mechanics transformed the understanding of atoms from indivisible billiard balls to complex, probabilistic systems with internal structure. The term “atom” remains central in physics and chemistry, though contemporary science regards atoms as composed of smaller constituents and described by quantum theory rather than classical indivisibility.

Today, atomism continues to influence discussions in both science and philosophy, illustrating how a simple idea about indivisible units can guide explanations of matter, change, and the structure of the natural world.