Before a war military science seems a real science, like astronomy; but after a war it seems more like astrology.

West’s aphorism contrasts the aura of precision that surrounds military planning before hostilities with the retrospective sense of arbitrariness that follows real combat. “Astronomy” evokes a disciplined, predictive science governed by stable laws; “astrology” suggests pattern-seeking, post‑hoc rationalization, and the illusion of foresight. The line captures a recurring modernist skepticism—sharpened by the world wars West reported on—about expert systems that promise control over chaotic human events. It implies that war exposes the limits of models, doctrines, and staff calculations: once outcomes are known, strategists can always invent explanations, but those explanations may be closer to divination than to genuine prediction.