Many of us might have heard quotes similar to the first one, if not the second one. Many history teachers say this to motivate us to learn history. I agree to this, but will try to understand from the perspective of a philosopher named Deleuze.
Differences are the engine of life. When there is pressure difference, wind flows. When there is potential difference, current flows. When there is height difference, water flows. Thus difference is leading to some creation or production. Deleuze considers life as a constant becoming (a flow).
Let us assume that there is an event called A (where difference exists and is considered a problem), it leads to another event called B. B is the actual event, but it is a becoming from the event called A. Many a times history might point to the event called B; more researched books may also point to the event called A. In Deleuzian language, B is one of the actualization of the potentiality of A. Now the interesting point is that, A has various potentialities and it could have given rise to various possibilities like C, D etc.
When the study of history includes the potentialities of A and different actualization that are possible (like B, C, D…), we may not repeat the historical blunders of yesterday or blindly follow even a historical success story as contextual variations do exist.
Thus for Deleuze, this process is not limited with history, but it extends to literature or any event. We shouldn’t be just interested in the text (as in literature) or an event, but should try to see the problem (difference) that cause the event or the text. The experience of different potentialities and possibilities associated with the problem (difference) opens up a much richer world infront of us.
[I know this was written in a little technical way.. Hope you got something…]