Explanation
Common ground comprises information, assumptions, and commitments that participants treat as mutually available for a particular interaction. What matters is not that they happen to know the same fact, but that they rely on its shared availability when designing and interpreting utterances. After entering a room together, “the door” may therefore require no further explanation. Utterances depend upon this ground while also changing it: assertions propose additions, questions mark unresolved areas, and corrections withdraw earlier assumptions. Common ground is neither complete nor static. Misunderstanding reveals that what appears to be shared must repeatedly be tested, negotiated, and repaired through the unfolding sequence of interaction.
Movement of thought
1. Participants enter an interaction with only partly overlapping knowledge. 2. They treat selected information as mutually accessible and available for continuation. 3. An utterance uses this ground to establish reference and initiate inferences. 4. A response, question, or objection tests whether the presumed overlap actually holds. 5. The exchange leaves an altered ground on which the next linguistic action can build.
Scientific use case
Conversation analysis can trace introductions of referents, presuppositions, acknowledgements, and repairs across turns. Experiments can vary what speakers witnessed together and measure when they choose fuller descriptions.
Example
After walking through a building together, one person says, “Let us meet again at the threshold.” The definite description succeeds because both treat one salient threshold as jointly identifiable.
Counterexample
If two people independently know the same fact but have no reason to assume the other's knowledge, it does not automatically belong to their common ground. Shared information is not necessarily mutually recognised as shared.
Distinction
Distinguish common ground from coincident knowledge, context, and discourse worlds. It requires treated mutual availability; context is broader, while a discourse world may contain introduced fictional or hypothetical entities.
Effect on thought and perception
Common ground determines what may remain unspoken, which references succeed, and which inferences become immediately available within an interaction.
Resonance
Each utterance meets what has already been sounded together and changes its reverberation as the condition for a subsequent response.
Cite this entry
Reich, Michael (Hrsg./ed.): „Common ground“. Atlas der Sprache, AT-PRA-0004. ATLAS 260, data model 1.6.0. https://atlasoflanguage.com/concept/AT-PRA-0004The address remains stable; editorial content may evolve. Editorial reading state: 2026-10-15. Include your access date for precise references.
Historical background
Locke makes successful communication depend partly on speakers not treating an established language as a private code. His appeal to common use supplies a historical comparison for common ground, but not the later technical model of what interlocutors mutually take for granted. Shared word conventions are only one possible component of that model. The Atlas should distinguish knowing the same vocabulary from knowing that both parties recognise a relevant fact or commitment. An original example asks whether an instruction can rely on a previous agreement that only one participant remembers. That question goes beyond Locke’s selected passage. The historical source illuminates a coordination problem while leaving the modern English term, its theoretical definitions and interactional evidence to direct later research. Familiar words alone cannot certify shared understanding.
How conceptual history changes the analysis
Common ground is publicly coordinated availability, not merely parallel knowledge. Analysis must identify how participants can recognise that an assumption is shared for the present exchange.
References for the historical section
- John Locke, An Essay Concerning Human Understanding, Books III–IV; Project Gutenberg ebook 10616 · Book III, IX §4 and XI §11: shared signification and common use
Selected passage, not a complete genealogy or an English first-attestation claim. Original Atlas applications are editorial interpretations, not reported experiments. Named historical passage read in transcription; no complete edition collation or adoption of historical normative assumptions.