In addition to what others said, things get rediscovered many times before the discovery takes hold. Think of it like a beneficial DNA mutation. The circumstances have to be just right for it to survive. In retrospect we find a lot of discoveries that were forgotten for years, decades or centuries. And earlier in human history those would not leave any artifacts for us to find.
In addition to what others said, things get rediscovered many times before the discovery takes hold. Think of it like a beneficial DNA mutation. The circumstances have to be just right for it to survive. In retrospect we find a lot of discoveries that were forgotten for years, decades or centuries. And earlier in human history those would not leave any artifacts for us to find.