Secondly, history is not incredible. In the view of post-modern historiography, history is not the reduction of past reality, but the competition and choice of different texts, or in other words, different statements/proposals. Marx also pointed out that the ideology of a period often has its material basis and realistic basis, and any argument is not produced out of thin air.
Therefore, if history is regarded by historians of different times as a narrative rather than a record of the past, then history can not only be assumed, but also be completely composed of assumptions. The reason for saying "impossible hypothesis" is that the narrator's narrative challenges the existing and recognized historical narrative, in short, subverts the public's cognition, or violates the cultural strategy of the ruling class.
The question of whether history can be assumed is also related to the contingency and inevitability of history in theory. Unlike literature and philosophy, history pursues a necessity. Although there are infinite possibilities at any stage of history, only this "road" is finally presented to us, so the so-called "inevitability of history" has become a puzzle for many people.
For example, social scientists try to put forward laws and explain their inevitability in an empirical way, but many times history is like this for endless reasons, which is why many people explain history with absolute things similar to providence, such as Hegel's "absolute spirit". I recommend reading hayden white's Meta History, Anckers Mitt's Historical Expression and lovett's World History and Salvation History (translated by Li).