How to Scale Confidence to Evidence
Scaling confidence means letting evidential support determine the strength of belief.
Separate Direction From Weight
First ask which direction the evidence points. Then ask how much it should move confidence. Many people stop after direction: they find something that supports their view and treat it as decisive. Scaling requires the second question.
Use Confidence Bands
A practical scale helps: below 0.5 means leaning against, around 0.5 means unresolved, 0.6 to 0.7 means tentative support, 0.7 to 0.85 means substantial support, 0.85 and above means strong support, and near certainty should be rare.
These bands are not laws. They are guardrails against treating every favorable consideration as proof.
Check for Inflation
Ask whether your confidence would look excessive if someone you disagreed with used the same evidence. If so, you may be scaling by desire rather than support.
Adjacent References
These are starting points rather than exhaustive citations. They connect this page to nearby work in probability, calibration, cognitive bias, and social epistemology.
- |Thomas Bayes, "An Essay towards solving a Problem in the Doctrine of Chances" (1763).
- |E. T. Jaynes, Probability Theory: The Logic of Science (2003).
- |Daniel Kahneman and Amos Tversky, "Judgment under Uncertainty: Heuristics and Biases" (1974).
- |Sarah Lichtenstein, Baruch Fischhoff, and Lawrence D. Phillips, "Calibration of Probabilities" (1982).