I often hear that China is the oldest civilization in the world. Ive heard it is the only existing surviving civilization from ancient times. 3500 years of written history and at least 3500 of unrecorded history before that!
I’ve tried to find the answer to the above question and it generally is something like “we can consider China the same civilization as it was 1000s of years ago because it maintained cultural identity” but surely there are multiple civilizations that have achieved this? What about when China was conquered by the mongols? What defines an ongoing civilization through government changes, being conquered, border changes, etc...?
Thanks for your time
About statements such as"China is the oldest civilization", "China is the only existing surviving civilization from the ancient times", "China had 3500 years of written history...". I can tell you that they are not proved and can't be proved. These statements most likely are created for the use of propaganda. It's something for political needs if you know what I mean.
One of the reasons why China's government urged to say that China is the oldest civilization may related to Chinese traditional political culture. In Chinese history, emphasizing continuity is a way to build-up legitimacy. While P.R.C is not a democratic government and its legitimacy does not base on people's consent. Claiming that everyone has the same glorious history and origin, which is the way of nationalism, is the best way for CCP to maintain its political status.
"China has 3500 years of written history and at least 3500 of unrecorded history", is a statement that created under such background, the result of the Xia-Shang-Zhou Chronology Project. Xia-Shang-Zhou Chronology Project was a project commissioned by P.R.C in 1996. 200 experts were gathered by authority and assumed that the Xia Dynasty might be founded in the 2070B.C and the Shang Dynasty might be founded in the 1600B.C or 1556 B.C. So that's the reference of "China has 5000 years history". However, the result was highly disputed among scholars. The earliest explicit calendar era in Chinese history is 841B.C which is the era of Gonghe Regency. To confirm dates that further than 841 B.C still faces numerous obstacles.
As you said, current China is a completely different thing from the past dynasties in whatever aspect. It is meaningless and impossible to prove whether P.R.C and the past dynasties are the same civilization or not. In the process of development, each generation inherits something from their ancestors and pass on to the coming one. So, of course, we can find similarities among the different generations which considered the same community. They are similar and that's all, not the same. People in Tang, Qing, and P.R.C might all be considered as Chinese in their existing era. But the fact is they are different in many ways. We don't have to think about why China is the only existing surviving civilization from ancient times because this is something related to political correctness more than history.