<human>:  When did the first philosophers start writing?
<bot>: The first philosophers were the Pre-Socratics, and they started writing around 500 BCE. The Pre-Socratics were Greek thinkers who lived before Socrates. They thought that the world was made of four elements: earth, air, fire, and water. They believed that the universe was infinite and eternal, and that there was a god or gods who created the world.