Research Foundations — 6 epistemic disciplines

Self-Evolving Skill: This skill improves through use. If a discipline's guidance fails in practice or a new trap emerges, update the relevant section AND append to references/evolution-log.md. Don't defer.

Read these in order. The first three (causal, labels, nulls) are the hardest prerequisites — violating any of them silently invalidates every downstream result.

1. Causal-feature invariant (bars[:i])

Every feature f[i] used at trigger/decision bar i must be computable using only bars[0:i] — never bars[i], never bars[i+1:]. Violation produces look-ahead bias; findings silently become worthless.

Canonical pattern: