ANAXIMENESMiletus, 585 - 525 B.C.
Ancient Greek natural philosopher and scientist from Miletus. His heyday falls in the 6th century BC (he died between the years 528 and 525). He was certainly younger than his fellow-citizen Anaximander, but the tradition, which presents him as his pupil, simply means that he continued in his line in the field of investigation of the natural world.
Anaximenes considered "air" to be the beginning of everything, starting from the specific material body that spreads around us and whose mobility anyone can observe. "Air" is the only element that is normally distributed in space and as such is suitable to sustain, contain and hold everything. And the most important thing is that air is the most subtle matter that is identified with "spirit" or "soul", the principle of life. The world is conceived as a great living organism that breathes air and is animated by it. And the human soul is but a thin breath of air that keeps the human organism alive. In the Anaximenes' system, the main characteristic is the transposition of temperature differences into density differences: warmer - thinner, cooler - denser. Thus all things fall into a certain degree on the cosmic scale of temperature, which corresponds to a certain degree of density of elemental matter (ie air).
The Earth is a flat body, a shallow "ship" suspended in the air. And the celestial bodies are flat discs that slide through the air. These are composed of fire and have a core of solid matter that remains invisible. Anaximenes was probably the first to notice that the Moon borrows its light from the Sun. Besides, he explained the rainbow as a result of the reflection of the sun's rays in a mass of condensed air, and with genuine scientific talent he also described the phenomenon of the phosphorescence of the sea. He seems to have given a dominant position to the Sun: the Sun is in the center, between the Moon and the stars, and is illuminated in all directions. The mythical belief that the sun god is sovereign over all and sees everything gives way to a scientific view.
Our world is not the only world there is. The vast mass of air simultaneously contains innumerable worlds that are constantly being born and dying, returning to the original infinite nebula.