“This foreknowledge cannot be elicited from spirits; it cannot be obtained inductively from experience, nor by deductive calculation.”
Real foreknowledge is not mysticism or pure reasoning; it comes from human sources — go to them.
Chapter 13 rules out the comfortable sources: this foreknowledge cannot be elicited from spirits; it cannot be obtained inductively from experience, nor by deductive calculation. Three exclusions, each aimed at a respectable habit — divination, pattern-matching on the past, and pure reasoning. All three feel like knowing and none of them is. What remains, Sun Tzu says plainly, is people.
A strategy team spends a quarter modeling a competitor’s likely pricing response — building the deck’s centerpiece from induction (what they did in 2021) and deduction (what a rational actor would do). A rival spends two weeks doing something unfashionable: coffee with six people who had left that competitor in the last year. The ex-employees mentioned the pricing committee’s new mandate — a fact no model contained, because it existed in no dataset, only in people.
People-sourcing is not rumor-trading — Sun Tzu’s sources are cultivated, positioned, and cross-checked, and Chapter 9’s signs still discipline the analysis. Nor does the verse dismiss analysis; it dismisses analysis pretending to be knowledge. The sequence is honest: reason about what you learn from people, and never reason instead of learning.