MATHEMATICIAN, ASTRONOMER, PHYSICIST

Life
Democritus was a philosopher and physicist, master of all the sciences and the founder of atomic physics. He was born in 460 BC in the Thracian city of Abdera, a place renowned for its wealth and its high intellectual level. His father, called either Hegesistratus or Athenocritus, was apparently a very wealthy man, and spent lavishly on his son's education. He is known to have studied with Leucippus, and Aristotle cites both teacher and student as founders of the atomic school: later, after the pupil had outstripped the master, his name stands alone as sole representative of the school. Democritus travelled widely, visiting Egypt, Babylon, Persia, possibly India, and Athens and exhausting his great wealth in the process; so that he returned to Abdera a poor man, but delighted with all he had seen and learned. At first his compatriots scorned him as a prodigal, but once they had recognised his wisdom they came to love and respect him. He lived to a great age, and when he died was buried in Abdera with great honours. The school he founded survived in Abdera for many years after his death, at first adhering faithfully to his teachings, but eventually turning towards Stoicism and Epicurism.

Democritus was a man with an all-embracing mind, as is evident from the scope of his writings, of which unfortunately only fragments remain. His philosophy incorporates virtually the entire body of knowledge of his age, while in their impressively comprehensive range his works can only be compared with those of Aristotle.


Work
His greatest achievement was the formulation of the atomic theory. He used the concepts of "full" and "empty" in order to explain phenomena, imagining "full" as being divided into innumerable imperceptibly tiny particles, separated one from another by a void. These particles are indivisible, as their Greek name "atoma" [= that cannot be cut] indicates, and solid ("nasta"). These particles have the same properties as Parmenides' "on": they are incorruptible, uncaused, unalterable, infinite in number, without qualitative difference, differing from one another only in arrangement, position and magnitude. Physical creation is formed by atoms that move and compound. Since all atoms are made of the same substance, it follows that their weight is exactly proportional to their size. The difference in weight between compound bodies of the same size is explained by the greater amount of empty space in the lighter of them. Every "coming-into being" of a compound is an association of separate atoms, and every "perishing" is a dissociation of atoms. Every change must be attributed to a change in the position or order of the compounding atoms. All the properties of a body are based on the shape, magnitude, position and arrangement of its atoms. There is however one basic difference: some properties (weight, density, hardness) belong to the compounds as such, while other, the so-called sensory properties, those which we ourselves attribute to things, reflect the manner in which they act upon the object sensed. Just as the atoms are uncaused and eternal, so too, according to Democritus, is motion: instead of a moving principle (the Love and Strife of Empedocles; the nous or intelligence of Anaxagoras), Democritus posited a system inherent in matter itself, in which a whirling motion (dine) brought atoms together. Motion has no beginning, the number of atoms and the surrounding void have no limits; and thus there are an infinity of worlds in an infinite variety of states and forms.

According to Diogenes Laertius, Democritus wrote some 70 treatises; of these, only fragments survive in the works of later writers. His most important works (by general category) are:

1. PHYSICS (books 25): "Great World System (Megas Diakosmos) ", ""Lesser World System" (Micros Diakosmos), ", "Cosmography", "On the planets", "On nature", "On the nature of man", "On the mind", "On senses", "On flavours", "On colours", "On the different states", "On successions of states", "Determining forces", "On images", "On the rules of logic´", "On disputed points", "Celestial causes" (celestial mechanics), "Causes relating to air" (aerostatics), "Causes relating to the plane" (statics), "Origins of fire and of fiery states" (heat and thermodynamics), "Origin of sounds" (acoustics), "Origin s f seeds and plants and fruits" (biology), "Origins of animals a, b, c" (zoology), "Origins of divers things" (miscellany), "On minerals" (mineralogy).

2. MATHEMATICS (5 books): "On a difference of opinion or on the contact between a circle and a sphere", "On geometry", "Geometry", "Numbers", "On irrational lines and solids".

3. ASTRONOMY - GEOGRAPHY (8 books): "Planispheres", "The Great Year", "On water clocks", "Description of the heavens", "Description of the firmament", "Radiation", "Geography", "Circuit of the ocean".

4. TECHNICAL SCIENCES (6 books): "Prognostics", "On the seasonable and the unseasonable", "On agriculture", "On drawing", "Tactics", "On the art of war".

5. PHARMACEUTICALS (1 book): "On medicaments", a treatise on nostrums and remedies, including a preparation to ensure the birth of "fair children": a mixture of fir seeds, balsam, saffron, honey, milk and wine.