The Democritus atomic model is one of the earliest known theories about the nature of matter. Democritus of Abdera, a Greek philosopher who lived around the 5th century BC, was one of the first to propose that everything in existence is composed of tiny, indivisible particles called "atoms" (from the Greek "á-tomos," meaning "without division").
The idea that matter is made up of separate units is very old. It appeared in many ancient cultures such as Greece and India. The word "atom" comes from ancient Greek. ἄτομος , meaning "indivisible", was invented by the pre-Socratic Greek philosopher Leucippus and his disciple the Greek philosopher Democritus (460-370 BC).
One of the characteristics of this atomic model is that Democritus defined the concept of an atom as the smallest portion into which a chemical element could be divided. Democritus claimed that the number of atoms is infinite, they are not created and are eternal, and the qualities of an object depend on the types of atoms that compose it.
This theory was later improved and developed by the later Greek philosopher Epicurus (341-270 BC) and the Roman Epicurean poet Lucretius (99-55 BC).
Although Democritus' atomic model was an innovative idea and one of the first attempts to understand matter from a naturalistic perspective, it was not supported by experimental evidence. The atomic theory was not widely accepted in his time due to the influence of other philosophers, such as Aristotle, who had a contrary view based on the idea of the four elements (earth, air, fire and water).
The idea of atoms was taken up again many centuries later, especially with the work of scientists such as John Dalton in the 19th century, who revived the atomic concept based on experimental evidence.
Key principles of Democritus' atomic model
The most important elements that define the atomic model proposed by Democritus of Abdera are the following:
Indivisibility of atoms
Democritus proposed that matter is composed of indivisible particles called atoms .
According to him, they could not be broken down into smaller parts; it was the ultimate limit of division. For him, any substance, if cut into smaller and smaller pieces, would eventually reach a particle that could not be divided any further, and that was the atom.
This idea contrasted with earlier views that believed that matter was continuous and could be divided infinitely. Although we now know that atoms are composed of subatomic particles (protons, neutrons and electrons), Democritus' idea was revolutionary for its time.
Diversity of shapes and sizes
Democritus believed that atoms varied in shape, size, and arrangement . These differences, he theorized, were responsible for the different properties of materials. For example:
- Atoms in hard substances, such as iron, may have more complex or intertwined shapes.
- Atoms in liquids, such as water, could be soft and smooth, allowing them to flow easily.
- Different combinations of atoms in shapes and sizes would create the different types of matter and properties observed in the world.
Although he had no way of observing atoms directly, Democritus arrived at these conclusions through a logical process based on the observed characteristics of substances.
Empty space (void or "kenón")
In order for atoms to move and change places, Democritus postulated the existence of a vacuum surrounding the atoms. This vacuum allowed the atoms to move and form new combinations.
According to his theory, if there were no void between atoms, matter would be solid and motionless. This idea of empty space was crucial to his model, as it explained how substances and objects in the observable world could change.
The concept of a vacuum was radical in its time, as most philosophers, such as Aristotle, rejected the existence of a vacuum, arguing that space must be filled with some substance.
Eternal movement
Atoms, according to Democritus, were in constant and incessant motion. This motion was eternal and spontaneous, without the need for an external cause to initiate or maintain the motion.
This idea contradicted previous theories that suggested that change in the world required the intervention of some kind of divine force or agent.
The movement of atoms allowed them to collide with each other, combine and form new structures and, in this way, explained changes in nature, such as growth, decomposition or the transformation of substances.
Mechanical nature of the universe
Democritus' model is mechanistic in nature , meaning that it does not rely on supernatural explanations or mysterious forces to explain natural phenomena.
Everything in the universe, from solid objects to living beings, was composed of moving atoms, and all changes and processes in the world could be understood as the result of collisions, unions and separations of these atoms. In this sense, his vision of the universe was deterministic : natural phenomena could be explained entirely through the material interactions between atoms, without the intervention of divine wills.
Infinity, non-creation and eternity of atoms
One of the fundamental principles of Democritus' atomism is the conception of atoms as infinite , uncreated , and eternal entities . This point is essential to understanding his materialistic view of the universe and the immutable nature of matter.
Infinity of Atoms : Democritus postulated that the number of atoms in the universe is infinite . This idea allowed him to explain the diversity of forms and phenomena in the world. Being infinite, atoms can combine in unlimited ways, which justifies the existence of all the variety of objects, beings and observable phenomena. Furthermore, being infinite, atoms are never exhausted, and the combinations of matter continue constantly in the universe.
Uncreated Atoms : According to Democritus, atoms were not created nor can they be destroyed, implying that the universe had no origin in time. In his model, atoms have always existed and will continue to exist eternally. This eliminated the need for any divine or supernatural intervention to explain the origin of matter, as the universe simply is and always has been.
Eternity of Atoms : The idea that atoms are eternal and unchanging is crucial to his vision. Although objects composed of atoms can transform, decompose, or change, the atoms that make them up remain intact and permanent . This eternity of atoms guarantees the indestructibility of matter at its most fundamental level, ensuring that even though the observable world changes, the basic components of reality remain constant.
Evolution of the Democritus model
Democritus' atomic model, formulated in the 5th century BC, was a pioneer in proposing that matter is composed of indivisible atoms. However, it lacked experimental evidence and was relegated to the side of Aristotle's theory of the four elements, which dominated scientific thought for centuries.
Atomism was revived by Epicurus in the 4th century BC, who introduced the idea of clinamen (spontaneous deflection of atoms) to explain free will. This version was spread by the Roman poet Lucretius in his work "De rerum natura" .
It was not until the 17th century, with the advance of modern science, that atomistic ideas re-emerged. Philosophers such as Pierre Gassendi revived atomism as an alternative to Aristotelian and scholastic views. Then, in the 19th century, John Dalton developed the first modern atomic theory based on experimental evidence. Dalton's atomic model proposed that each element is composed of unique atoms and that chemical reactions are combinations of these atoms. This represented a major evolution from the atomism of Democritus, now supported by experiments.
In 1897, JJ Thomson discovered the electron. Thomson's atomic model demonstrated for the first time that atoms were not indivisible, as Democritus had thought, but that they had an internal structure.
In the early 20th century, Ernest Rutherford and Niels Bohr refined the model, revealing a central nucleus with protons and neutrons surrounded by orbiting electrons.
Finally, the quantum mechanics of Heisenberg and Schrödinger completed the picture, describing the probabilistic behavior of subatomic particles.
Philosophical atomism
Atomism is a natural physical and philosophical theory, according to which sensually perceived (material) things consist of chemically indivisible particles - atoms. It has its origins in ancient Greek philosophy. It was mainly developed in the field of philosophy and science of the Middle Ages and Modern Times.
The term atomism is used in two senses.
- In a broad sense, atomism refers to any doctrine of atoms.
- In a strict sense, the ancient Greek philosophical school of the 5th - 4th centuries BC NS, whose teaching is the oldest historical form of atomism.
In both cases, the term atomism is also used. The term atomistic materialism is more restricted, since some proponents of the doctrine of atoms considered atoms to be ideal.
Democritus is considered the principal founder of philosophical atomism . Together with his teacher Leucippus , he was one of the first to propose that the universe is composed of atoms and emptiness.
Democritus took atomism beyond mere physical speculation into a complete philosophical worldview , where everything that happens is a product of the material interactions of atoms. This idea fits within his materialism , which denies any dualism between matter and spirit.