And you are correct. You do know stuff, but some of what you know might, in fact, be as mythopoetic as any "stuff" people knew before Thales of Miletus came along. Remember him. He's kind of the first major "scientist," the first to take the West out of mythopoetry and place it on the road to Newton, Einstein, and CERN. Now, admittedly, Thales was neither the first to observe the natural world nor the first to comment on it. He did, supposedly, predict an eclipse in 585 B.C.E., but he didn't leave any appreciable writings. For Thales' accomplishments and contributions to the rise of a scientific West we pretty much have to go on the word of others, such as the Aristotelian writer Simplicius. "Okay," you say, "if that's what you know."
Well yes, that's what I know, but then Simplicius wrote about Thales a millennium after Thales died. Probably, we have to just take Simplicius' praise of Thales as a bit of mythopoetry in itself. So, anyway, Thales seems to have taken whatever knowledge about the natural world that was available and used it with sufficient skill to do some legit astronomical work. And he probably also dabbled in other natural phenomena.
Why should we even bother with a philosopher/scientist who lived two and a half millennia ago? If he could visit us today, he might give us a new perspective on our knowledge just as he gave people of the ancient world a new perspective.
Thales started us down the path of knowledge that is neither myth nor poetry, a new kind of knowledge; call it "scientific" if you want. Was he an original thinker? Or was he just a good student who repeated what he heard in a land of intellectual opportunity? He lived in what we might call the birthplace of western philosophy and science: Miletus in the sixth century before Christ. As his remote intellectual descendants, we are now committed to establishing scientific knowledge by irrefutable means while still wondering whether or not we haven't missed something about the natural world in what we accept as fact. It's that lingering doubt that we have "proved" something that just isn't quite more than mere belief or fantasy. In the line of intellectual heritage that runs from Thales to us lies Heraclitus. Heraclitus might have hit the proverbial nail of mythopoetry on the head when he wrote in Fragment 15 that Nature likes to hide.*
In all our chasing about to master the natural world, we now pursue what we cannot see or even test. We're pretty much committed to our explanations of atoms because our knowledge of them shows itself in practical applications in chemistry and nuclear physics. But for decades now we've been chasing after "strings" without anything beyond formal, that is, mathematical, explanations. Although we have come to rely on numbers and formulae because they seem to be really good at representing reality as they do in chemistry and physics, still numbers and formulae are only a "formal" way of knowing. Numbers and formulae might say that strings exist and that we don't yet have proof of them because they are wrapped up in such tiny, invisible forms they defy not only observation, but also concrete discovery. We cannot at this time detect them. We have no experimental evidence and no product from them like polymers and nuclear power that our knowledge of atoms provides. Are strings mythopoetry? And since a scientific theory is the demonstrable consensus, why do we call "String Theory" a theory?
Are "strings" the new ether?** They might make sense formally and metaphorically just as the ether did in the nineteenth century, but since we can't yet even devise an experiment that makes them show up as an irrefutable part of our universe, are they an example of mythopoetry? Do they really make up subatomic particles and underlie the fabric of the universe? And if we actually find them, will we not look for some new more fundamental mythopoetic foundation of the universe? Are we no different from the ancients in our desire to find some mythical basis for the cosmos?
What do you think Thales might say if he were made aware of our current understanding of the universe? Would he say, for example, "Yes, I see what you are saying and how you advanced what I started, and you certainly know more about physical reality than I knew. You're welcome. But these string things into which you and many physicists put so much money and effort don't at this time seem much more than the mythopoetry of my ancestors."
Look at your surroundings for a moment. How much of what you understand will withstand the test of time? How many of your explanations about why the world is what it is will withstand that test? How much of your knowledge is mythopoetry, knowledge that you think "sounds good enough to accept as reality"? I know what you're going to say. You want to say your knowledge is adequate to get you through your current life, just as the knowledge of the ancients got them through their lives. Is there a difference between truly knowing something and relying on poetic myth as a handy metaphor for understanding? Do we ultimately, because as Heraclitus says, "Nature likes to hide," all rely on partial explanations and myth since our lives are short?
* For his discussion on Thales and mythopoetry, I recommend Richard G. Geldard's Remembering Heraclitus, and his chapter on Physis. Lindisfarne Books, 2000.
** The ether was the supposed medium through which light waves passed. It was our mythopoetic reality for quite some time until the Michelson/Morley experiment.