Koherentnost

Koherentnost is a term used in multiple disciplines to denote a form of internal consistency or unity among parts of a system. It emphasizes stable, compatible relations rather than mere aggregation of elements. Etymologically, it derives from Latin cohaerent-, meaning to stick together.

In physics and engineering, coherence refers to a fixed phase relationship between waves at different points in space or time. Temporal coherence concerns phase stability over time; spatial coherence concerns phase alignment across distance. High coherence enables pronounced interference, while low coherence reduces it. Coherence length is a common measure; lasers are noted for high coherence, while thermal sources are relatively incoherent. Coherence functions quantify the degree of correlation between signals.

In linguistics and discourse studies, textual coherence describes the semantic and logical unity of a text. Coherence arises from how ideas are related, referenced, and developed, beyond the presence of explicit linking devices. It complements the notion of cohesion, which focuses on surface connectors and reference.

In philosophy and logic, coherence theory of truth holds that the truth of a belief depends on its coherence with a system of beliefs. In logic, a set of propositions is coherent if it is simultaneously satisfiable; inconsistency leads to incoherence.

In probability and statistics, coherence denotes internal consistency of a set of probability assessments or forecasts. A coherent assignment avoids sure losses in all possible betting scenarios, a concept central to de Finetti’s coherence criterion.

Coherence has additional specialized meanings in other fields, such as signal processing and quantum mechanics, where it describes correlated phase relations and superposition states.