In his An Introduction to Ancient Philosophy Arthur Hillary Armstrong, probably best known for his masterful translation of Plotinus' Enneads (used in the Loeb edition of Plotinus), talks about the early development of Greek philosophy in Ionia, that is, the Greek city-states along the western coast of Anatolia (modern day Turkey), which at the time were "probably the richest and most highly civilized of the Greek communities."
The early Ionian philosophy is represented by a succession of three men, Thales, Anaximander and Anaximenes [the first, Thales, was born sometime around 625 BC, and the last, Anaximenes, died around 528 BC], all from Miltetus, at that time the richest and most powerful of the Ionian cities. Hence the group collectively are sometimes called the Milesians. The first, Thales, by tradition one of the "Seven Wise Men" of Greece, seems to have written nothing and our scanty knowledge of his teaching depends on a tradition which goes back no further than Aristotle, and though the other two each seem to have written a work in prose, these works have perished, and Aristotle is again our earliest source for their teaching. Our knowledge of it therefore is uncertain and fragmentary .... There do, however, seem to be a few things about the three men's personal interests and activities and about the picture of the universe they put forward of which we can be fairly certain. First of all, they were much concerned with those technical skills which along with magic and astrology formed the substance of the ancient priestly wisdom of Babylonia and Egypt, and which the Ionians introduced into the Greek world, mainly from Babylonia. They were practical astronomers, land-surveyors and geographers. Thales predicted eclipses, Anaximander is said to have invented the sundial, made the first map, and been responsible for several important astronomical discoveries. They were greatly interested in the 'meteora', the phenomena of the regions above the surface of the earth, the weather and the movements of the heavenly bodies.... Practically all that we know about the philosophy of the Milesians concerns their cosmogony, their account of how the world came into being. They postulate as the first reality a single living stuff, indefinite in extent and character, from which the world and all things in it develop spontaneously. Thales called this 'moisture' or more accurately 'the moist' (to hugron0, moisture being the principle of life according to simple observation and primitive common sense. Anaximander called it the 'Apeiron', a word which means either 'indefinite' or 'unbounded' rather than 'infinite'. He may have thought of it as spherical like the Orphic world-egg; for later Greek geometers the sphere was 'apeiron'. Anaximenes called it air or breath. It appears that, like many other ancient philosophers, he held that the life of the universe resembled that of man, with air, the breath of life of which the human soul is made, for its principle. This stuff they call 'divine' by which they probably mean no more than that it is living and everlasting, two characters which it must have if it is to be for them a sufficient explanation of the cosmic process. [pp. 1-4]One very important thing to emphasize about Milesian cosmogony is that it starts with some kind of pre-existing material, and the rest of the cosmos "develop[s] spontaneously" from that. In other words their approach is exactly the opposite of the Christian notion of "creation out of nothing". Another crucial thing to note is that the "first reality" (as Armstrong calls it) is already living, in addition to being everlasting and uncreated. This is the exact opposite of the modern secular humanist view of "dead matter". The conclusion is pretty obvious: these ancient Greek Pagans had a view of the world utterly different from either Christians or modern day atheists/secularists. Theirs was a cosmos that required no "Creator" in the Christian sense, nor did it require an explanation for how life could "evolve" from dead matter. Theirs was a cosmos that had always existed, and had always been alive.
The following is from the entry for Presocratic Philosophy in the online Stanford Encyclopedia of Philsophy (the author of this entry is Patricia Curd, a philosophy Professor at Purdue University):
The pattern that can be seen in Thales and Anaximander of an original basic stuff giving rise to the phenomena of the cosmos continues in the views of the third of the Milesians, Anaximenes. He replaces Anaximander's apeiron with air, thus eliminating the first stage of the coming-to-be of the cosmos (the something productive of hot and cold). Rather, he returns to an originating stuff more like Thales' water. In 13A5, Aristotle's associate Theophrastus, quoted by Simplicius, speculates that Anaximenes chose air because he agreed that a basic principle must be neutral (as Anaximander's apeiron is) but not so lacking in properties that it seems to be nothing at all. Air can apparently take on various properties of color, temperature, humidity, motion, taste, and smell. Moreover, according to Theophrastus, Anaximenes explicitly states the natural mechanism for change; it is the condensation and rarefaction of air that naturally determine the particular characters of the things produced from the originating stuff. Rarified, air becomes fire; more and more condensed, it becomes progressively wind, cloud, water, earth, and finally stones. “The rest,” says Theophrastus, “come to be from these.”It is significant that the last of the three Milesians, Anaximenes, settled on air/breath as the most basic "stuff" of the cosmos. Stoics did not adopt this view exactly, but they did keep the idea that the entire cosmos is everywhere permeated with pneuma, and that it is by way of this everpresent, continuous pneuma that the effects of cosmic sympathy are transmitted. Cicero, in his De Rerum Natura (I.10.26) says that Anaximenes called air "the divine". Thomas McEvilley in his The Shape of Ancient Thought says that Cicero believed that Anaximenes "may have been influenced by the belief that air, or breath, is soul-stuff, that is the carrier of consciousness. The universe, on that account, is a pantheos which has the divine air element as its breath-soul." McEvilley then links this to later Pythagorean thought:
The Pythagoreans, not long after, would teach similarly that the universe is a living organism which breathes one vast breath ... the universe was viewed as a living god.