We consider Thales the first scientist because...

We consider Thales the first scientist because, as far as we can tell from the admittedly incomplete historical record, he was the first to approach the world from a scientific perspective. He wondered how the universe came to be and came up with an answer far different from that depicted in the creation of the gods myth of Hesiod's Theogony (8th century B.C.). It seemed to him that all things either came from moisture or were sustained by moisture.

So he concluded that the universe grew from water. According to Thales the earth was a flat disc floating on a sea of water. The unique element in the cosmology of Thales was the idea that the universe developed over time through natural processes from some undifferentiated state. The first recorded use of a physical model in explaining a natural phenomenon is Thales belief that earthquakes were caused by disturbances in the water that supported the earth.

As with any human being, Thales was of course constrained by the level of knowledge available at the time and by the cultural and intellectual context in which he found himself. It is clear that the earlier mythopoetic tradition exerted a strong influence on him. For example, from Aristotle we learn that included in Thales' metaphysical and cosmological doctrines was the idea that inanimate objects that move and are moved (magnets and iron, amber and wool) possess souls.

It's hard to know what Thales meant by this exactly, but on the surface of it, it doesn't strike us as scientific. There is an additional, more subtle, nonscientific element in Thales view. His two primary assumptions about the origin of the world were 1) that the present world order arose out of some preexistent state and thus had a beginning in time, and 2) that this world order occurred by a process of differentiation from a previous state.

These beliefs are not suggested by an unbiased observation of nature itself, at least not as it was known to Thales. He must have come to this conclusion for deeper, perhaps subconscious, reasons. Similar psychological pre-dispositions have continued to play a role in science through to the present day. Thales had a student named Anaximander (610-546 B.C.). He introduced the notion of a spherical universe, an idea that survived for more than 2000 years.

He saw the earth as suspended in space (rather that floating on water). He also believed that living creatures arose from the moist elements when it had been partially evaporated by the sun.