Docs / Studies / Studies.Kaplan1989
Kaplan, D. (1989). In Themes from Kaplan (pp. 481–563). Oxford University Press
A sentence is valid in Kaplan's logic of demonstratives when it is true at every context, and
necessary when what it says at every context is true at every world. Necessity implies validity
(Kaplan.Character.IsNecessary.isAPriori), but necessitation fails
as soon as there are two worlds, and for
sentences whose content does not vary with the context it holds only if every world is the world
of a context. α = dthat[α]
is valid, and necessary exactly when α is directly
referential; I exist and I am here now are
valid but contingent.
ProperContext): over every tuple, I exist would be true at every context only if every agent
existed at every world, and so would be necessary.Validity implies necessity for every sentence exactly when there is at most one world.
The identity of a term with its rigidification is necessary exactly when the term is directly referential.
For sentences whose content is the same at every context, Kaplan's stable characters, validity implies necessity exactly when every world is the world of some context.
A context is proper when its agent exists at its world and is at its position at its time there.
Used by ProperContext
Used in Schlenker2004a
The proper contexts.
Built from
Used by existsAgent, locatedAgent, isAPriori_existsAgent, isAPriori_locatedAgent, actualContext, model_isAPriori_not_isNecessary
The character of I exist: the agent of the context exists at the world of evaluation.
Built from
Used by isAPriori_existsAgent, model_isAPriori_not_isNecessary
The character of I am here now: the agent of the context is at its position at its time in the world of evaluation.
Built from
Used by isAPriori_locatedAgent, model_isAPriori_not_isNecessary
Built from ,
I am here now is valid.
Built from ,
The actual world and one alternative.
Derives DecidableEq, Repr.
Used by existsAt, locatedAt, worldOfEvaluation
The only agent exists at the actual world alone.
Built from
The agent is wherever it exists.
Built from
The only proper context of the model.
Built from , ,
I exist and I am here now are valid but not necessary: the actual world is the world of the only proper context, and what both say there is false at the alternative, where no one exists.
Built from , , , ,
The description the world of evaluation, which is not directly referential.
Built from