more on this theme     |     more from this thinker


Single Idea 15414

[filed under theme 5. Theory of Logic / F. Referring in Logic / 2. Descriptions / b. Definite descriptions ]

Full Idea

By contrast to rigidly designating proper names, …the denotation of definite descriptions is (in general) not rigid but flexible.

Gist of Idea

The denotation of a definite description is flexible, rather than rigid

Source

John P. Burgess (Philosophical Logic [2009], 2.9)

Book Ref

Burgess,John P.: 'Philosophical Logic' [Princeton 2009], p.35


A Reaction

This modern way of putting it greatly clarifies why Russell was interested in the type of reference involved in definite descriptions. Obviously some descriptions (such as 'the only person who could ever have…') might be rigid.


The 28 ideas from 'Philosophical Logic'

Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess]
Philosophical logic is a branch of logic, and is now centred in computer science [Burgess]
Classical logic neglects the non-mathematical, such as temporality or modality [Burgess]
Formalising arguments favours lots of connectives; proving things favours having very few [Burgess]
'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess]
'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess]
All occurrences of variables in atomic formulas are free [Burgess]
We only need to study mathematical models, since all other models are isomorphic to these [Burgess]
Models leave out meaning, and just focus on truth values [Burgess]
With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess]
The temporal Barcan formulas fix what exists, which seems absurd [Burgess]
The denotation of a definite description is flexible, rather than rigid [Burgess]
We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess]
Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess]
Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess]
General consensus is S5 for logical modality of validity, and S4 for proof [Burgess]
De re modality seems to apply to objects a concept intended for sentences [Burgess]
Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess]
Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess]
It is doubtful whether the negation of a conditional has any clear meaning [Burgess]
Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess]
We can build one expanding sequence, instead of a chain of deductions [Burgess]
The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess]
The Cut Rule expresses the classical idea that entailment is transitive [Burgess]
The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess]
Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess]
Is classical logic a part of intuitionist logic, or vice versa? [Burgess]
It is still unsettled whether standard intuitionist logic is complete [Burgess]