Sticky Idea

First-principles thinking vs Second order thinking

Both are ways to think more clearly than the crowd, but first-principles thinking questions your starting assumptions, while second-order thinking questions where a decision leads beyond its first effect.

	First-principles thinking	Second order thinking
What it is	Breaking a problem down to its basic truths, then reasoning up	Tracing the consequences of a consequence, not just the first effect
Question it asks	"What do I actually know to be true here?"	"And then what happens?"
Guards against	Reasoning by analogy or convention	Stopping at the obvious, immediate result

Which matters when?

Use first-principles thinking when you want to question the assumptions everyone else is copying. Use second-order thinking once you've made a decision and want to know where it actually leads. One rebuilds the foundation; the other follows the ripple.

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