Pre Socratic Philosophy Before Heraclitus and Parmenides

Thales wasn't the first philosopher. The first person to wonder was. Thales, however, was the first we have recorded of asking the question of origins without recourse to religion. His questions were essentially, what is the source of all things, and is the source one or many. Anaximander followed closely behind Thales with the first recorded philosophical debate. He argued that water, which Thales thought was, could not be the source of all things, because water is by nature differentiated. You can't get something from what is not there, and it doesn't appear that water can produce all things. Rather, Anaximander argued that "the unbounded" or "apeiron" was the source of all things, because only the unbounded could be undifferentiated enough to produce all things. What is interesting is that Anaximander resorted to arguing for something essentially unobservable. So we have our first real debate: can there exists non-observable entities? Can such an entity be the source of all things?