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By adopting smaller and smaller units of motion we only approach the solution of the problem but never reach it. It is only by admitting infinitesimal quantities and their progression up to a tenth, and taking the sum of that geometrical progression, that we can arrive at the solution to the problem.
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Only by assuming an infinitesimally small unit for observation — a differential of history (that is, the common tendencies of men) — and arriving at the art of integration (finding the sum of the infinitesimals) can we hope to discover the laws of history.
War and Peace.
Leo Tolstoy waxes nerdy on calculus. Emphasis added.