Actually I have been unable to find any verifiable attestation on Monsieur Buonaparte ever writing or stating this famous quotation.
Any help on this search would be highly welcomed.
Anyhow, such search is not the matter of this thread; the matter is the military mistake as the main contributor to determine the outcome of the vast majority of battles all along History.
Because as most collective human enterprises War is inherently first and foremost teamwork.
For any optimal performance of the team the complementary best contribution of each and any member is an absolute requirement.
On the other hand, for the whole team to fail (e.g. defeat) the failure on the contribution of any indispensable member of the team is all what is required.
Ultimately, it's easy to verify that any member of the team at the battlefield might (and empirically does) eventually become indispensable.
It is therefore easy to understand why defeat in general overwhelmingly comes from the malfunction of just one (or at worst a few) single indispensable parts...
... And not from the simultaneous independent coincidental crash of all the parts.
In practice, this fact implies that regarding any non-stalemate battle, the regular truly relevant question should not be:
"Why did the victor win
"Why did the other side lose?
There's a related recent thread on the requirements for a victorius army.
As a side note (and as timely pointed out in such thread) from the above exposition it seems clear that the single major requirement would be to find a loser opponent, i.e. someone that one would be able to defeat with some certainty.
Lat say like the Spanish Conquistadores did in Mesoamerica & the Andes plateau.
Naturally, any other of the myriad conceivable requirements for any victorious army should be discussed in the aforementioned thread.
The point here is again just about the discussion of the military mistake
as the ostensible major contributor for the outcome of the vast majority of (if not all) battles (ergo wars) ever.
Under this approach, any battle would fundamentally be a long series of mistakes from both (or any number of) sides.
Victory would overwhelmingly (in fact, inevitably) go to the side who might commit less and lesser mistakes.
I.e. not so much for any individual epiphanies or miraculous strikes of genius.
Please share with us any thoughts, educated opinions, reflections and relevant hard evidence on this fascinating issue.
As usual, any contribution will be highly welcomed.
Thanks in advance