Thales of Miletus (624 BC – 546 BC) was a pre-Socratic philosopher, mathematician and astronomer and one of the Seven Sages of Greece. Aristotle in particular considered him the first true philosopher in the Greek tradition. Thales was the one who broke the practice of seeking mythological explanations for all natural phenomena. Instead, he attempted to explain the world and the universe through theories and hypotheses. That is why he is now considered a precursor of modern science. A strong piece of science is that, according to the Greek historian Herodotus, he predicted the solar eclipse of May 28, 585 BC. would have predicted. Thales’s best-known theory is that water is the primordial element, the substance from which everything is made up.
Background
During the Archaic period (mid 8th – 6th centuries BC), the peoples of the Greek peninsula gradually settled into a group of city-states. They developed an alphabetic system of writing, as well as the beginnings of what is now recognized as Western philosophy. Previous civilizations had relied on religion to explain phenomena in the world around them; now a new wave of thinkers emerged who tried to find natural, rational explanations. The first of these new scientific thinkers was Thales of Miletus.
Life of Thales
We know very little about the life of Thales (624 BC – 546 BC). What we do know is that he was born in the Greek colony of Miletus, on the coast of what is now Turkey. None of his writings have survived. However, his reputation as one of the most important early Greek thinkers seems well deserved, as he is mentioned by both Aristotle and Diogenes Laertius, the 3rd century biographer of the ancient Greek philosophers. Thales was not only a philosopher, but also a successful businessman who was actively involved in politics. He traveled extensively in the eastern Mediterranean. During a visit to Egypt he is said to have learned practical geometry, which would form the basis for his deductive reasoning. However, Thales was above all a teacher, the first of the so-called Milesian School of philosophers. His student Anaximander expanded his scientific theories and in turn became a mentor to Anaximenes, who is credited with teaching the young mathematician Pythagoras.
Everything is water
Believe in gods
Although he is rightly reputed to be the West’s first scientific explorer, Thales by no means denied the existence and role of the gods. In his search for primordial matter (Greek: arche) he started from living matter : he was a ‘zyloist’, who believed that things were animated by gods and spirits. Yet it was his great merit not to immediately look for a divine cause behind every event that is difficult to explain.
Aristotle and Simplicius on Thales
From Aristotle we learn:
- that Thales found in water the origin of things;
- that he saw the earth as a floating flat disk on a sea of elemental fluid.
Aristotle suggests that Thales was led to his theory by observation of the role moisture plays in the production and maintenance of life. Simplicius (4 90 – 560 BC) suggests that Thales chose the element water because it could be converted into other substances by dilution and thickening.
Thales in search of the primordial substance
Thales asked himself the question: ,What is the basic material of the cosmos?, The idea of reducing everything in the universe to one substance is now called the theory of monism , and Thales and his followers were the first to propose it within Western philosophy.
Thales reasoned that the fundamental material of the universe had to meet a number of conditions:
- it had to be something from which everything else could be formed
- it had to be essential to life
- and are capable of movement and therefore change.
He notes that water is clearly necessary to sustain all forms of life, and that it moves and changes, taking different forms. After all: water turns into steam when heated and becomes a solid when frozen. Water was thus the sole causal principle behind the natural world. Thales therefore decided that all matter, regardless of its apparent properties, must be water in some stage of transformation.
Obscure statement
In any case, ,Everything is water, remains an obscure statement. Even Aristotle – who lived almost 3 centuries later! – had to guess how and why Thales came to the conclusion that all matter can be traced back to the primordial substance water. Since Thales was the founder of his own school, the School of Miletus, the theories of his principal students, Anaximander and Anaximenes, shed some light on the matter. They too were diligently searching for the primordial substance, and came to very different conclusions. Anaximenes of Miletus stated: ,all is air,, and Anaximander: ,all is apeiron, ‘the indefinite’. Heraclitus, a philosopher from Ephesus, built on the research of the Miletic school. He then arrived at the, if possible, more obscure statement: ,everything is fire,. In fact, it would only be with the atomism of Democritus (,everything is made up of indivisible atoms,) that something recognizable that comes close to modern science would emerge. However, credit where it’s due: Thales remains the pioneer who gave the impetus to scientific research into matter!