Atomism (from ancient Greek atomos, meaning “uncuttable”) is a natural philosophy that developed in several ancient traditions. The atomists theorized that the natural world consists of two fundamental parts: indivisible atoms and empty void.
According to Aristotle, atoms are indestructible and immutable and there are an infinite variety of shapes and sizes. They move through the void, bouncing off each other, sometimes becoming hooked with one or more others to form a cluster. Clusters of different shapes, arrangements, and positions give rise to the various macroscopic substances in the world.
References to the concept of atoms date back to ancient India and ancient Greece. In India the Jain, Ajivika and Carvaka schools of atomism may date back to the 6th century BC. The Nyaya and Vaisheshika schools later developed theories on how atoms combined into more complex objects. In the West, the references to atoms emerged in the 5th century BC with Leucippus, and Democritus. Whether Indian culture influenced Greek or vice versa or whether both evolved independently is a matter of dispute. (Wikipedia)
Since the Greek word atom means unsplittable, many of the atomists’ hard-core materialistic views fell with the splitting of the atom. Contemporary materialists, however, still believe that all reality is comprised of physical energy which, according to the first law of thermodynamics is neither being created nor destroyed.
The belief in the eternality of matter (physical energy) has [stalled in the face of] the second law of thermodynamics which reveals that the physical universe is not eternal, but is running down. (Norman Geisler)
Atomists try (tried) to view the world as consisting of these microscopic building blocks (atoms) which operate randomly and independent of each other; their chaotic motion brings about energy and structure. Some atomists believe that a ‘god’ created the atoms and set them in motion and now is separate from this ‘creation’; others, deny a Creator God.