1. Terminology and sources of uncertainty

1.1 Terminology

The term "uncertainty" is often used in conjunction with other terms such as "imprecision", "confidence", "ambiguity", "vagueness" and "fuzziness". The uncertainty of a piece of information is judged by qualifiers such as "probable", "possible", "necessary", "plausible" and "credible".

Probable has an essentially physical connotation linked to the frequency of occurrence of an event, i.e. its natural variability.

The possible has an epistemic connotation, linked to a subjective judgment about its conformity to a frame of reference (reality, the objectives of the study, etc.): in this case we speak of belief.

Ambiguity is a form of imprecision linked to language: information is ambiguous when it...