What is fact vs opinion?

Fact vs opinion is a concept in personal epistemology: A claim and its supporting evidence are different objects that should be stored separately.

Example: You write a note: 'Remote work increases productivity — Buffer's 2023 survey found 98% of respondents want to continue working remotely.' This note fuses a claim (remote work increases productivity) with evidence (a survey about preferences, which is not even evidence of productivity). Stored as one object, the claim inherits false credibility from the citation, and the evidence can never be reused to support a different claim. Separate them: one note states the claim, another records the survey finding, and a link connects them. Now you can see that the evidence doesn't actually support the claim — and you can link that same survey data to a different argument about employee preferences.

This concept is part of Phase 2 (Atomicity and Decomposition) in the How to Think curriculum, which builds the epistemic infrastructure for atomicity and decomposition.