# First-Principles Thinking **The principle:** Strip a problem to its irreducible facts — the foundational truths that cannot be deduced from anything else — and rebuild your reasoning from there. Resist arguing from analogy, convention, or "the way it's always been done." Aristotle defined a first principle as "the first basis from which a thing is known." Munger's entire latticework approach is a first-principles method: don't inherit your framework from your profession; build it from the actual structure of reality. The danger of analogy-based reasoning is that it imports assumptions from the source domain that may not hold in the target domain. First-principles thinking exposes those imported assumptions. ## The Mechanism **Decomposition.** Break the problem into its fundamental components. "Government is inefficient" decomposes into: What specific functions does government perform? What would it cost to perform them privately? What does "efficiency" mean for functions whose purpose isn't profit (public safety, environmental protection, justice)? The decomposition often reveals that the original claim rests on analogies that don't survive examination. **Assumption surfacing.** Most reasoning is built on inherited assumptions that were never examined. "Tax cuts create growth" rests on assumptions about marginal propensity to invest, labor market effects, and demand dynamics that can each be tested individually. First-principles thinking surfaces these assumptions so they can be evaluated rather than inherited. **Analogy detection.** The most common form of lazy reasoning is argument by analogy: "government should be run like a business," "the economy is like a household budget," "the Founders intended X." Each analogy imports the source domain's structure and assumes it maps onto the target domain. First-principles thinking asks whether the mapping actually holds. ## KB Applications ### Originalism's False First Principles [[Originalism]] presents itself as first-principles reasoning — going back to the "original" meaning of the Constitution. But it actually imports a massive assumption: that the meaning intended by 18th-century elites in a slaveholding republic is the correct framework for 21st-century governance. Genuine first-principles analysis of constitutional law would ask: What is the purpose of a constitution? What principles best serve that purpose in current conditions? What institutional designs produce the outcomes constitutional governance is meant to achieve? Originalism skips these questions and substitutes a historical analogy — the Founders' intent — for first-principles analysis. ### "Government as Business" Analogy The most consequential analogy failure in the KB is "government should be run like a business." First-principles analysis reveals the disanalogy: businesses exist to generate profit for shareholders; governments exist to provide public goods, enforce rights, and maintain social order. Businesses can fire customers (by refusing service); governments cannot fire citizens. Businesses optimize for one metric (profit); governments balance dozens of competing values (safety, liberty, equality, prosperity, justice, security). The analogy imports a single-metric optimization framework into a multi-objective system, producing DOGE-style "efficiency" that optimizes for cost while ignoring everything government is actually for. ### Supply-Side Decomposed First-principles analysis of [[Supply-Side Economics]]: - Claim: "Cutting taxes on the wealthy increases investment, which increases growth, which increases revenue." - Decompose: Does cutting taxes on the wealthy actually increase investment? (Evidence: much goes to stock buybacks, not productive investment.) Does increased investment automatically produce growth? (Depends on demand conditions.) Does growth produce enough revenue to offset the cut? (Empirically, never has.) Each link in the chain has testable assumptions. When tested, most fail. But the chain is rarely decomposed because it is presented as a package — a first-order narrative that resists decomposition because decomposition would reveal its weakness. ### Social Contract from First Principles [[Social Contract Theory]] is genuine first-principles political philosophy: it asks "why does government exist?" and builds upward from the answer. Locke's answer (to protect natural rights) and Rousseau's answer (to express the general will) are different first principles that produce different institutional designs. The value of the exercise is that it makes the foundations explicit rather than inherited — you can agree or disagree with Locke's premises, but at least you can see them. The NRx/Yarvin rejection of social contract theory is *also* first-principles reasoning (from different premises: that humans are unequal, that democracy produces bad outcomes, that corporate governance is more efficient). The debate between these frameworks is a first-principles debate — which is exactly where the most consequential political disagreements should be fought, rather than at the level of inherited analogy. ## Practicing First-Principles Thinking 1. **Identify the analogy.** When someone makes a political argument, ask: "What is this being compared to, and does the comparison hold?" "Government is like a business," "the national debt is like a household budget," "immigration is like an invasion" — each is an analogy that imports assumptions. Test whether those assumptions survive. 2. **Decompose the claim.** Break any political claim into its component assumptions and test each one independently. "Tax cuts create growth" becomes three or four separate empirical questions, each of which can be evaluated. 3. **Ask "why?" repeatedly.** Why does this institution exist? Why does this policy take this form? Why do we assume this structure is necessary? Each "why" strips away a layer of inherited convention and gets closer to the first principle underneath. ## See Also - [[Originalism]] — First-principles reasoning replaced by historical analogy - [[Supply-Side Economics]] — A chain of assumptions that resists decomposition - Reason-Respecting Tendency — First-principles analysis tests whether the "reason" is genuine or decorative