I have frequently heard that China is the "world's oldest continuous civilization", and I believe this to be true on the basis of the fact that the historical records show that China has been a literate society since the Shang Dynasty, which roughly corresponds to the beginning of the Greek dark ages, at a time when Greek writing was lost. Since Shang oracle bone scripts are direct ancestors of modern Chinese script, then the Chinese writing system is older than the Western (Greek) one, and China has the world's oldest continuous writing system, which defines the difference between one civilization and another.
However, that is just something I worked out myself. Apart from this, what authoritative sources, if any, underline the claim that China is the world's "oldest continuous civilization"? Where does this claim come from?