Separate facts from assumptions explicitly
Sort what you actually know from what you’re assuming, in two visible columns.
Why it works
Facts and assumptions blur together in the head, so assumptions get treated as constraints they are not. Externalizing the split into two explicit lists works by making the assumptions visible and therefore challengeable; an assumption you can see is one you can test or drop. Visibility is what turns a hidden constraint into a choice.
How to do it
- Draw two columns: “Verified facts” and “Assumptions I’m making.”
- Force every belief into one column; if you can’t prove it, it’s an assumption.
- Attack the assumption column — which ones, if false, would change everything?
Evidence
A practical externalization technique consistent with research on how offloading reasoning to external representations reduces cognitive load and surfaces hidden premises. Mechanistic. (mechanistic)
Offloading research is general; the specific two-column fact/assumption split is a heuristic built on it, not a studied protocol.
Sources
- Research on external representation / cognitive offloading in reasoning and problem-solving
Common mistake
Filing assumptions in the “facts” column because they feel certain. The whole value is in being ruthless about what truly belongs as fact.
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More practices for First-Principles Thinking, Made Usable
- Deconstruct the problem to its fundamentals
Break the problem into the few things you actually know to be true, with no inherited conclusions.
- Reason up from the parts, not by analogy
Build the solution from the fundamentals you kept, rather than copying an existing template.
- Use Socratic questioning to test each belief
Interrogate every claim with “how do I know this is true?” until only bedrock remains.
- Drill down with the five whys
Ask “why?” repeatedly to move from a surface symptom to the root constraint.
- Rebuild from fundamentals and stress-test it
Reassemble a solution from verified parts, then attack it to find where it breaks.