Anaximenes: Is the Universe a Machine?

Philosophers and scientists have long wrestled with notion of a mechanistic universe: it is attractive, to the extent that it reflects both the formalized assumptions and intuitive concepts of physics and chemistry, both of which can be modeled mathematically. On the other hand, it fails to correspond to our ideas of imagination, creativity, and chance. We can see clearly that some aspects of the cosmos are mechanistic - gravitational forces can be calculated and reliably predicted. But is there a decision process which would have allowed us to predict, after Beethoven finished his eighth symphony, which form and content would comprise his ninth symphony?

Anaximenes was perhaps the first to advance a strictly mechanistic cosmology. Even though Thales and Anaximander had rejected mythological “psyche” into their systems of physics, attributing something like a capability for arbitrary decisions to objects. Modern physics would like to tell us that even in a situation like the flipping of a coin, the results are, if not actually calculable, still in principle calculable. Anaximenes would agree. Yale’s Professor Brumbaugh writes that Anaximenes

discovered that nature can be explained mechanically. Anaximenes thought that all changes were the result of changes in density brought about by the condensation and rarefaction of one underlying form of matter.

And this, in fact, is not far from current twenty-first century natural observational science. The vast majority of what is around us consists of three rather generic forms: electron, proton, neutron.

The great virtue of this new idea was that it gave the scientist experiments, models, and clear-cut physical explanations of changes and their causes. This is still our own way of thinking.

If we review the first three philosophers in succession - Thales, Anaximander, and Anaximenes - then we can see their cumulative progress:

To recognize the magnitude and importance of the Milesian achievement, with its three progressive insights into the materiality, uniformity, and mechanical causality of nature, the modern reader must realize that here we have the ancestors of contemporary physics and astronomy.

These first three philosophers lived in the town of Miletus, and are thus called Milesian; their lifespans overlapped and so they almost certainly knew each other. Anaximenes additionally proposed the notion of rotation as central to the universe, and so it is: planets rotate on their axes, orbit their stars, and a grouped into larger galaxies which also rotate and orbit. This notion of rotation fits well with his primary notion of density:

Modern astrophysics can trace the life histories of starts in terms of alternate increases and decreases in their density.

And so, Anaximenes has made a persuasive case for a mechanistic universe. Yet the counterexamples remain: artistic creativity among humans, the uncertainty principle in physics, and the question of the origin of the universe. Anaximenes is persuasive, but not conclusive.