# Sources — second-order-thinking

> *Primary and authoritative sources for the [second-order-thinking](../SKILL.md) skill.*

- Howard Marks, *The Most Important Thing* (2011) and Oaktree Capital memos — "second-level thinking": first-level thinking is "simplistic and superficial," second-level is "deep, complex and convoluted"; the edge comes from being non-consensus *and* correct, because obvious conclusions are already priced in. https://www.oaktreecapital.com/insights/memo/i-beg-to-differ
- Henry Hazlitt, *Economics in One Lesson* (1946) — "the fallacy of overlooking secondary consequences": "The art of economics consists in looking not merely at the immediate but at the longer effects of any act or policy; it consists in tracing the consequences of that policy not merely for one group but for all groups." https://en.wikipedia.org/wiki/Economics_in_One_Lesson
- Terminology note: Marks's term is "second-level thinking" (commonly also "second-order thinking"); the "secondary / second-order consequences" framing traces to Hazlitt and to systems theory (feedback loops, non-linear causation). The popular label is not the source — the reasoning is.