1. Introduction

Milesian in origin, son of Eurystratos, the last of the Ionian natural philosophers from Miletus (Thales, Anaximander, Anaximenes). The peak of his life is dated to the second half of the 6th century BC. He died during the 63rd Olympiad (528-525 BC).¹

2. Activity-teaching

We do not know much about the life and work of Anaximenes and any information concerning him comes from later testimonies.² He wrote in Ionian dialect, in a simple and plain prose, according to Diogenes Laertius, although his style has many poetic attributes.³ Most of our sources, however, prove to be clearly influenced by the Aristotelian reading of his work. Aristotle deliberately presented the Milesian natural philosophers as materialists-monists, who were seeking the material principles of being, unique and unchanged.⁴ Thus our image for Anaximenes’ work, since it comes from Aristotle and the Peripatetic philosophers (Theophrastus,⁵ Aetios⁶) proves to be anachronistic and problematic for any interpretation.⁷

The air (aer) holds central position in his natural philosophy. It is the generative substance of the world, the beginning of the existence, eternal and unlimited.⁸ He was probably led to the choice of this specific element from the four fundamental elements of nature by the mythological background (Chaos, Night) as well as by empirical data such as humidity, the other times warm and other times cold human breathing etc.⁹ The world according to Anaximenes came from the evolutional metamorphosis of the air. With the influence of the powers of condensation (pyknosis) and rarefaction (araiosis) the initial condition, where there was only air, was submitted into a series of changes which followed the scheme air>clouds>water>earth>stone.¹⁰

According to Anaximenes’ cosmology Earth is trapezoidal, wide and flat, this is why it remains stable, since due to its width it rides the air underneath.¹¹ This formulation reminds us of Thales’ view that the earth is supported by water, floating motionless on it like a piece of wood.¹² The stars are born from the earth, from the soil: humidity comes out of the earth, then rarefies and is transformed into fire, which in turn is lifted up on the sky and forms these bodies, the sun and the stars, which are made of fire. The stars move around the earth (“exactly like a small cap rotates around the head”) and are also flat and wide and ride the air, like the sun and the moon.¹³

In Anaximenes’ cosmogony the earth is born from the condensation of the air and from it the sun, the moon and the rest of the stars are born in turn.¹⁴ Anaximenes also explained, based on the ideas of condensation and rarefaction, the creation and the course of the winds, the natural phenomena of rain and thunder (important for a naval city like Miletus), but also of earthquakes and of the rainbow.¹⁵ These testimonies show the practical character of the Ionian natural philosophy and the philosopher’s correspondence to specific problems and needs of the societies where he lived.

Finally, if the testimony of Aetios that Anaximenes identified the soul with the air is valid, then his psychology can be placed in the exegetic scheme of the air as the beginning of the being, and the human soul is transformed into a miniature of the universe. Thus the testimony of Galen that Anaximenes considered that man was totally made of air is explained.¹⁶

3. Evaluation of his personality-judgments

Our knowledge for Anaximenes and his way of thinking has hardly been improved, compared to that for other Ionian natural philosophers (e.g. Thales, Anaximander, Heraclitus). His way of thinking has not occupied a great number of scholars and the relative bibliography remains small and incomplete. However, this traditional philological evaluation has already been reversed. Anaximenes is no longer considered inferior to Anaximander neither the location of his basic principle into one of the four material substances; water is considered to be a retrograde compared to the infinite as a principle of Anaximander's monism.

Modern scholars view him as a more systematic and subtle researcher than Anaximander and question the doxographic tradition which considered him a student of Anaximander and a teacher of Anaxagoras.¹⁷ His way of thinking is evaluated as more complicated than the one of a materialist-monist. He is an important philosopher who is entitled to be characterized as a scientist more than the other contemporary Ionians, even in an early form which lacks the experimental method.¹⁸ With the condensation and the rarefaction, Anaximenes is now believed to be the first who developed a theory which aimed in a precise description of the course of transformation of the principle element, of the primeval material of the world. His way of thinking influenced directly Diogenes Apolloniates but probably also the meaning of the “spirit” in the stoic philosophy as an active substance of the world. Echoes of the changes of the air are to be found in the Platonic dialogue Timaios (49b-c).