This post is one in a series on the Epistemology and Worldview Throughout History.
Previously in this series: The Worldview of the Theologos
As I discussed previously, Aristotle distinguished between thinkers who were theologi and thinkers who were physiologi. I discussed the former in my previous post, and now I shall discuss the latter.
"Logos" means "account" and "physis" means "nature". So while the theologi (poets, prophets, and priests) accounted for things with reference to gods, the physiologi accounted for things with reference to nature.
Many belief systems claim that god created nature. And Cicero wrote a treatise called "On The Nature of the Gods." So why would Aristotle consider these two approaches to be mutually exclusive? To answer that, one must understand Aristotle's conception of "nature."
Aristotelean nature is an endogenous drive of change or rest (or as many Aristotelean scholars say, an "inherent principle of change or rest"). The notion of the sun being driven by Helios and his divine horses does not account for the nature of the sun, because the drive moving the sun is exogenous; that is, it is driven by an outside force (that of the god and horses). Conceivably a study of the drives within Helios and his horses themselves would be both theologia and physiologia, since they concern the nature of the gods. However, Aristotle's clear-cut distinction probably comes from a recognition that most theologi say, "the gods did it," and stop there, without advancing to the explanation of how or why gods do things in the first place. Again, Aristotle seems to think of Hesiod as an honorable exception, because he seems to think of Hesiod's Eros as qualifying as an endogenous drive within the gods. So Aristotle might have considered Hesiod to be a member of both camps.
Still, it was Thales who Aristotle gave the honor of being called the first physiologos. Thales is often looked down upon by modern scholars for having said that all things have soul. This derision stems from a misunderstanding of what Greeks meant by soul (psuche). A soul was not necessarily the seat of consciousness (although it sometimes was). Psuche was the animating force within a body (as indicated by the fact that the Latin word for soul is anima). Taken thus, soul (psuche) is a particular type of nature (physis), since nature is an endogenous drive for change or rest, and soul is an endogenous drive for a particular species of change (animation). What Thales seems to have meant when he said that all things have soul is that things move according to their own natures (endogenous drives), and not according to the exogenous actions of mysterious gods.
For Thales and the theologi who followed him, the universe was full of things moving about according to their own natures. The interplay of these movements brought about mechanisms which explain the phenomena of the universe. For example, according to Anaximander (a student of Thales), thunder and lightning was not Zeus giving vent to his wrath; rather it was the heat and sound resulting from the collision of massive clouds.
With Thales and his followers, the cosmic praxeology of the theologi gave way to the mechanistic naturalism of the physiologi.
Next in this series: The Worldview of the Metaphysical Dualist