THALES of MILETUS (624 – 545 BCE)

bust of Thales


‘WATER is the basis of all matter’

Thales is remembered because he disregarded the classical, mythical understanding of life and the universe in favour of a more physical understanding. Thales and his followers worked with the conviction that there exist natural laws governing the behaviour of natural processes and that future events could be predicted by understanding these laws. One did not have to examine chicken entrails in order to understand the vagaries and whims of the gods who ultimately determined these events.
The basic principle that you can understand nature by studying these natural laws and what things are made of forms the foundation of future philosophy and science.

Born in Miletus on the Aegean coast, Thales engaged in disciplines as varied as engineering and statesmanship.
He had a belief that there must be a fundamental substance or building block from which everything else is made. His conclusion was that this was water. Water was essential for life, drink it and you will grow, take it away and everything dies. Water can exist in a solid form as ice or snow; a bowl of water left exposed will vanish into the air. Water, he thought, could readily be made very fine, in which case it becomes air; alternatively it could be compacted into a slime that becomes earth. Not only was everything made of this elemental substance, but also all life was supported on it, literally. The Earth, said Thales, floated on water.
There were two compelling strands of evidence. First, it couldn’t be supported by air because air was incapable of supporting anything, but water could hold up large objects like logs or ships. Secondly, you could observe the effects of the Earth floating on water in that on occasions it rocked suddenly – an earthquake. Quite obviously this was caused by the water’s movement.

Legend has it that Thales, while traveling in Egypt observed that the ratio of the length of a shadow and the height of an object is the same for all objects if measured at the same time of day, hence when his shadow was the same length as his height, then at the same moment the height of the pyramid would be equal to the length of its shadow.

Nothing remains of Thales’ original work, and all knowledge of him is derived from later philosophers. His way of thinking marks the beginning of a way of investigating the hidden nature of natural things by investigation and systematisation.






ANAXIMANDER of MILETUS (c.611 – c.547 BCE)

‘Apeiron is the basis of all matter’

mosaic of Anaximander


A pupil of THALES of MILETUS. As with Thales, little is known about Anaximander’s life and most of what we know comes from later Greeks, notably Aristotle and Theophrastus.
Anaximander conceptualised the Earth as suspended completely unsupported at the centre of the universe. It had been assumed by other thinkers that the Earth was a flat disc held in place by water, pillars or some other physical structure. Although without a notion of gravity, Anaximander supported his argument by supposing that the Earth, being at the centre of the universe, at equal distances from the extremes,

‘has no inclination to move up rather than down or sideways; and since it is impossible to move in opposite directions at the same time, it necessarily stays where it is’ – ( ARISTOTLE explaining Anaximander’s theory).

Moreover, because the Earth was suspended freely, it allowed Anaximander to propose the idea that the sun, moon and stars orbited in full circles around the Earth.

Anaximander proposed the idea of space or a universe with depth. Rather than the view of the Earth caged in a planetarium style ‘celestial vault’, he argued the celestial bodies (the sun, moon and stars) were different distances away from the Earth, with space or air between them.

Picture of head of statue said to depict ANAXIMENES ©


ANAXIMENES of MILETUS (c.585 – c.528 BCE)

‘AIR is the basis of all matter’



HERACLEITUS of EPHESUS (c.535 – c.475 BCE)

‘FIRE is the basis of all matter’

Thales’ pupil Anaximander avoided the issue of ‘prote hyle‘, or first matter by contending that all materials were composed of apeiron, the indefinite and unknowable first substance. Wanting to understand the transformations observed daily in the world, Anaximander believed that change came about through the agency of contending opposite qualities; hot and cold, and dry and moist.