I think more than learning from mistakes/history or whatever else, what we need to focus on is the application of the theory. Somewhere I believe it's comparable to the well-known debate on whether economics is a science and the classic (cliche?) line that all economic theories assume the consumer makes a rational choice, and in practice the consumer is anything but rational.

Similarly in a war, you have to make strategies and plans and not leave things to chance, but also remember that a small, seemingly inconsequential event could turn the tide in favour of or against you. I don't think Tolstoy meant his theory to be used to abandon all notions of learning, improvising or planning.

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