valleys of my Letus live during the 6th and 5th centuries BC in modern-day Turkey little is known for certain about thali aside from what other philosophers said about him but he is still an important figure for being the first pre-socratic philosopher the pre-socratics paved the way for the Socratic war classical philosophers who would establish the major themes of Western philosophy what we do know about the philosophy of Thalys is to the modern mind strange to say the least thou's is most famous for positing that everything is fundamentally made up of water yes that's really what he believed and he took it seriously but if you think about things from his perspective it actually starts to make sense hear me out valleys was trying to uncover the unifying principle of diversity to understand let's back up valleys was unique for rejecting the Greek pantheon of gods and looking for predictable laws in nature much like modern scientists in other words Thalys thought the world was rational orderly and understandable through investigation and inquiry this was a pretty new idea for the Greeks Greek gods were precarious and unpredictable constantly fighting and filling the world with chaos as well as order valleys was rejecting this notion that the world was a fairly random place full of unrelated forces that sometimes lost and sometimes won he had to justify his own model of the universe and if the universe was to be rational and orderly there had to be something more to it than lots of random unconnected parts there had to be something underneath everything unifying everything and describing diversity through unity to put it in ancient language valleys wanted to identify our key or unifying principle but our key is more than just a glue that holds everything together it also moves them because thou has wanted to explain life the universe is full of motion and action but why it could be dead still and lifeless our key is the source of this action and it also is the source of all life as such our key has a dimension of intelligence it permeates lives and moves if this sounds a lot like the force from Star Wars you're definitely starting to understand what our key is but there's a big and important difference valleys didn't think the our key was invisible or intangible but just assumed it was something material that could be touched and seen of all the elements valleys identified water as the our key so why water well think about it in ancient times the laws of physics were not well understood rivers flow to the sea waves crashed the tides went in and out water seemed to move all on its own since Thalys didn't know about gravity this apparently meant that water could move by itself solving the problem of motion and action secondly every living thing needs water humans can survive weeks without food but only three days without water animals need it and so do plants and insects if everything alive needs water water is clearly an important ingredient for life thirdly valleys believe that Earth originated from water and for good reason the Greeks knew that Islands sometimes appeared out of the middle of nowhere and didn't understand underwater volcanoes or plate tectonics he also believed that the earth floated on water and although that seems far-fetched we know from the historian Pliny that floating reed islands really existed in lydia not far from thous home some have also speculated that he was familiar with pumice a rare volcanic rock that can actually float on water fourthly valleys knew that substances can change forms metal workers were constantly melting down metal to make weapons or other tools and that was weird but it wasn't so weird if metal was made out of water because everyone knew that water could change from a solid to a liquid to a gas so water could explain motion life the origin of Earth and the ability of substances to transform of course we know now that Thalys was radically mistake and even Aristotle would call him out but Thalys was also a keenly observant scientist he famously managed to predict the solar eclipse of May 28th 585 BC and to this day we don't know how he did that this gave him credibility and shows just what a thoughtful person he was even though he was wrong about many things now he's used the little knowledge that he had to come up with good theories and thanks to him later pre-socratics would form new ideas about the world eventually leading to Socrates a man who had changed the Western world forever to hear about the rest of the pre-socratics and for more videos on famous philosophers like this video subscribe and leave a comment below thanks for watching you