Evidence

Evidence Is What Bears on a Claim

Evidence is not the same as whatever feels persuasive. Evidence is information that should rationally affect confidence in a claim. It can include observation, measurement, testimony, memory, experiment, background theory, statistical frequency, expert convergence, and the absence of a signal that should have appeared.

The same item can be strong evidence in one context and weak evidence in another. A single vivid story may matter when the claim is about one person, but it may be nearly useless when the claim is about a population.

Evidence Has Weight and Direction

Direction asks which hypothesis the evidence favors. Weight asks how much it should move credence. People often notice direction while exaggerating weight: they find something that points their way and treat it as decisive.

Credencing requires both questions. Does this support the claim? How strongly? Compared with what alternatives? Under what assumptions? With what error rate?

Evidence in the Model

Objective Evidence (E0) represents the evidential situation as it stands apart from the agent. Perceived Evidence (EP) represents what the agent takes that evidence to show. The gap between them is a measure of evidential misperception or processing error.

The model therefore does not assume that evidence reaches the mind cleanly. It passes through attention, incentives, framing, memory, statistical skill, and social context.

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).