History refers to the development process of objective things and people's understanding of this process; The logic here refers to the order and process reflected in the above-mentioned process in thinking.

The development process of history, especially objective things, is transcendental, which determines logic and is the basis of logic.

On the unity of logic and history, Engels pointed out: where history begins, the logic of the ideological process should also begin, and the further development of the ideological process is only an abstract and theoretically consistent formal reflection of the historical process; This kind of reflection is revised, but it is revised according to the law of the actual historical process itself. At this point, each element can be checked at its fully mature and exemplary development point.

But history itself contains countless details and accidental factors, and logic grasps history and its laws in theoretical form. This will inevitably abandon those details and grasp the main and essential things.

This is the "correction" of logic to history. Without this "revision", it is impossible to correctly grasp history. So we say that "history is the basis of logic, and logic is the revision of history" is the view that history and logic are unified.