Anaximenes, a disciple of Anaximander, proposed air, in Greek aér (ἀήρ), as the Arché of all things, and explained for the first time a mechanism, through rarefaction and condensation, capable of transforming this single principle into the multitude of things that exist.
A step back that is actually a step forward
At first glance, Anaximenes appears to retreat: after Anaximander's abstract and formless Apeiron, he returns to a concrete element, air. But it's not a regression. Thales and Anaximander had said which the principle was, water or the unlimited, but neither explained how a single principle becomes the variety of things that fill the world, stone, fire, water, people. Anaximenes is the first to answer this missing question, and his answer is the most modern of the three.
The mechanism: rarefaction and condensation
According to Anaximenes, the air, when rarefied, heats up and turns into fire. As it condenses, it cools and becomes, in increasing degrees of compression, wind, then cloud, then water, then earth, then stone (the condensation process was called, in Greek, pýknosis, πύκνωσις). The difference between hot and cold stops being a mysterious difference in quality and becomes a difference in quantity, in degree of compression, something that can in principle be measured.
The test you can do yourself
What makes Anaximenes special is the type of criteria he uses to support the idea: a proof that anyone can reproduce instantly. Blow into your hand with your mouth wide open, the air comes out hot, rarefied. Blow again, now with pursed lips, and the air comes out cold, condensed. Anaximenes sought an explanation that experience itself could test, rather than an explanation that could only be accepted or rejected on faith. It is science being born, still within philosophy, and it is also the closing of a cycle: Anaximander had corrected Thales, and now Anaximenes corrects Anaximander, with an argument, not with authority, exactly the habit that founded philosophy itself.
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What did Anaximenes say was the beginning of everything?
The air (in Greek, aér, ἀήρ). Unlike Thales and Anaximander, he not only named the principle, but also explained the mechanism by which this single principle turns the multitude of things we see: rarefaction and condensation.
What are rarefaction and condensation, in Anaximenes?
The process by which air, when rarefied, heats up and turns into fire; and, as it condenses, it cools and becomes, in increasing degrees of compression, wind, cloud, water, earth and stone. The difference between hot and cold becomes a difference in quantity, not quality.
Why is Anaximenes considered more modern than Thales and Anaximander?
Because he proposed a criterion that anyone can test right away: blow into your hand with your mouth open, the air comes out hot and rarefied; blow with pursed lips, it comes out cold and condensed. It is an explanation that seeks confirmation in experience, the embryo of the scientific method.
Continue: What is Anaximander's Apeiron? · Why the disciple must refute the master · Who were the pre-Socratics · Who was Anselm of Canterbury?
Source class (NousCast Community): Quem foram os Pré-Socráticos? O momento em que o mundo deixou de ser explicado por deuses