Ideas of Saul A. Kripke, by Theme

[American, b.1940, Born at Bayshore. Formerly professor at Princeton University.]

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1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
Kripke separated semantics from metaphysics, rather than linking them, making the latter independent
1. Philosophy / F. Analytic Philosophy / 5. Against Analysis
Analyses of concepts using entirely different terms are very inclined to fail
2. Reason / D. Definition / 2. Aims of Definition
Some definitions aim to fix a reference rather than give a meaning
3. Truth / F. Semantic Truth / 2. Semantic Truth
Kripke's semantic theory has actually inspired promising axiomatic theories
Kripke offers a semantic theory of truth (involving models)
3. Truth / G. Axiomatic Truth / 1. Axiomatic Truth
The Tarskian move to a metalanguage may not be essential for truth theories
Certain three-valued languages can contain their own truth predicates
3. Truth / G. Axiomatic Truth / 3. KF Truth Axioms
Kripke classified fixed points, and illuminated their use for clarifications
4. Formal Logic / D. Modal Logic ML / 1. Modal Logic
Propositional modal logic has been proved to be complete
Possible worlds allowed the application of set-theoretic models to modal logic
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
Names are rigid, making them unlike definite descriptions
Names are rigid designators, which designate the same object in all possible worlds
5. Theory of Logic / F. Referring in Logic / 1. Naming / b. Names as descriptive
A bundle of qualities is a collection of abstractions, so it can't be a particular
A name can still refer even if it satisfies none of its well-known descriptions
We may fix the reference of 'Cicero' by a description, but thereafter the name is rigid
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
Proper names must have referents, because they are not descriptive
A name's reference is not fixed by any marks or properties of the referent
The function of names is simply to refer
Some references, such as 'Neptune', have to be fixed by description rather than baptism
A man has two names if the historical chains are different - even if they are the same!
5. Theory of Logic / G. Quantification / 4. Substitutional Quantification
The substitutional quantifier is not in competition with the standard interpretation
7. Existence / D. Theories of Reality / 1. Realism
Kripke's metaphysics (essences, kinds, rigidity) blocks the slide into sociology
9. Objects / A. Existence of Objects / 4. Individuation / b. Individuation by properties
Kripke individuates objects by essential modal properties (and presupposes essentialism)
9. Objects / A. Existence of Objects / 5. Simples
We might fix identities for small particulars, but it is utopian to hope for such things
9. Objects / C. Structure of Objects / 6. Constitution of an Object
Given that a table is made of molecules, could it not be molecular and still be this table?
If we imagine this table made of ice or different wood, we are imagining a different table
A different piece of wood could have been used for that table; constitution isn't identity
9. Objects / D. Essence of Objects / 2. Types of Essence
For Kripke, essence is origin; for Putnam, essence is properties; for Wiggins, essence is membership of a kind
9. Objects / D. Essence of Objects / 5. Essence as Kind
Atomic number 79 is part of the nature of the gold we know
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
An essential property is true of an object in any case where it would have existed
De re modality is an object having essential properties
9. Objects / D. Essence of Objects / 9. Essence and Properties
Important properties of an object need not be essential to it
9. Objects / D. Essence of Objects / 10. Essence as Species
Given that Nixon is indeed a human being, that he might not have been does not concern knowledge
9. Objects / D. Essence of Objects / 14. Knowledge of Essences
An essence is the necessary properties, derived from an intuitive identity, in origin, type and material
9. Objects / E. Objects over Time / 1. Objects over Time
No one seems to know the identity conditions for a material object (or for people) over time
9. Objects / E. Objects over Time / 12. Origin as Essential
If we lose track of origin, how do we show we are maintaining a reference?
Kripke argues, of the Queen, that parents of an organism are essentially so
Could the actual Queen have been born of different parents?
Socrates can't have a necessary origin, because he might have had no 'origin'
9. Objects / F. Identity among Objects / 1. Concept of Identity
With the necessity of self-identity plus Leibniz's Law, identity has to be an 'internal' relation
9. Objects / F. Identity among Objects / 5. Self-Identity
A relation can clearly be reflexive, and identity is the smallest reflexive relation
9. Objects / F. Identity among Objects / 6. Identity between Objects
Identity statements can be contingent if they rely on descriptions
If Hesperus and Phosophorus are the same, they can't possibly be different
9. Objects / F. Identity among Objects / 8. Leibniz's Law
The indiscernibility of identicals is as self-evident as the law of contradiction
9. Objects / F. Identity among Objects / 9. Sameness
A vague identity may seem intransitive, and we might want to talk of 'counterparts'
10. Modality / A. Necessity / 2. Nature of Necessity
Kripke says his necessary a posteriori examples are known a priori to be necessary
10. Modality / A. Necessity / 7. Natural Necessity
What is often held to be mere physical necessity is actually metaphysical necessity
Instead of being regularities, maybe natural laws are the weak a posteriori necessities of Kripke
Physical necessity may be necessity in the highest degree
What many people consider merely physically necessary I consider completely necessary
10. Modality / B. Possibility / 1. Possibility
Unicorns are vague, so no actual or possible creature could count as a unicorn
10. Modality / C. Sources of Modality / 1. Sources of Necessity
I don't think possible worlds reductively reveal the natures of modal operators etc.
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
Kripke separates necessary and a priori, proposing necessary a posteriori and contingent a priori examples
A priori = Necessary because we imagine all worlds, and we know without looking at actuality?
10. Modality / D. Knowledge of Modality / 2. A Priori Contingent
The meter is defined necessarily, but the stick being one meter long is contingent a priori
The very act of designating of an object with properties gives knowledge of a contingent truth
10. Modality / D. Knowledge of Modality / 3. A Posteriori Necessary
"'Hesperus' is 'Phosphorus'" is necessarily true, if it is true, but not known a priori
Theoretical identities are between rigid designators, and so are necessary a posteriori
It is necessary that this table is not made of ice, but we don't know it a priori
Kripke has demonstrated that some necessary truths are only knowable a posteriori
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Instead of talking about possible worlds, we can always say "It is possible that.."
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
Possible worlds are useful in set theory, but can be very misleading elsewhere
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Possible worlds aren't puzzling places to learn about, but places we ourselves describe
Probability with dice uses possible worlds, abstractions which fictionally simplify things
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
If we discuss what might have happened to Nixon, we stipulate that it is about Nixon
Transworld identification is unproblematic, because we stipulate that we rigidly refer to something
A table in some possible world should not even be identified by its essential properties
Identification across possible worlds does not need properties, even essential ones
10. Modality / E. Possible worlds / 3. Transworld Objects / b. Rigid designation
A 'rigid designator' designates the same object in all possible worlds
Test for rigidity by inserting into the sentence 'N might not have been N'
Kripke avoids difficulties of transworld identity by saying it is a decision, not a discovery
If Kripke names must still denote a thing in a non-actual situation, the statue isn't its clay
A rigid expression may refer at a world to an object not existing in that world
We do not begin with possible worlds and place objects in them; we begin with objects in the real world
It is a necessary truth that Elizabeth II was the child of two particular parents
We cannot say that Nixon might have been a different man from the one he actually was
Kaplan's 'Dthat' is a useful operator for transforming a description into a rigid designation
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
Modal statements about this table never refer to counterparts; that confuses epistemology and metaphysics
The best known objection to counterparts is Kripke's, that Humphrey doesn't care if his counterpart wins
10. Modality / E. Possible worlds / 3. Transworld Objects / e. Possible Objects
That there might have been unicorns is false; we don't know the circumstances for unicorns
12. Knowledge Sources / A. A Priori Knowledge / 1. Nature of the A Priori
Kripke has breathed new life into the a priori/a posteriori distinction
Rather than 'a priori truth', it is best to stick to whether some person knows it on a priori evidence
A priori truths can be known independently of experience - but they don't have to be
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
Analytic judgements are a priori, even when their content is empirical
The a priori analytic truths involving fixing of reference are contingent
12. Knowledge Sources / E. Direct Knowledge / 1. Intuition
Intuition is the strongest possible evidence one can have about anything
14. Science / B. Scientific Theories / 1. Scientific Theory
Identities like 'heat is molecule motion' are necessary (in the highest degree), not contingent
15. Nature of Minds / A. Nature of Mind / 1. Mind / a. Mind
I regard the mind-body problem as wide open, and extremely confusing
17. Mind and Body / A. Mind-Body Dualism / 7. Zombies
It seems logically possible to have the pain brain state without the actual pain
Identity theorists must deny that pains can be imagined without brain states
17. Mind and Body / E. Physicalism / 1. Physicalism
Kripke assumes that mind-brain identity designates rigidly, which it doesn't
17. Mind and Body / E. Physicalism / 7. Anti-Physicalism / e. Modal argument
Identity theorists seem committed to no-brain-event-no-pain, and vice versa, which seems wrong
Pain, unlike heat, is picked out by an essential property
Kripke says pain is necessarily pain, but a brain state isn't necessarily painful
Identity must be necessary, but pain isn't necessarily a brain state, so they aren't identical
18. Thought / A. Modes of Thought / 10. Rule Following
'Quus' means the same as 'plus' if the ingredients are less than 57; otherwise it just produces 5
No rule can be fully explained
18. Thought / B. Mechanics of Thought / 4. Mental Files
Puzzled Pierre has two mental files about the same object
19. Language / A. Language / 7. Private Language
The sceptical rule-following paradox is the basis of the private language argument
19. Language / B. Meaning / 12. Denial of Meanings
Kripke's Wittgenstein says meaning 'vanishes into thin air'
If you ask what is in your mind for following the addition rule, meaning just seems to vanish
19. Language / C. Semantics / 4. Truth-Conditions Semantics
Community implies assertability-conditions rather than truth-conditions semantics
19. Language / C. Semantics / 7. Two-Dimensional Semantics
Rigid designation creates a puzzle - why do some necessary truths appear to be contingent?
19. Language / D. Theories of Reference / 3. Direct Reference / a. Direct reference
Kripke has a definitional account of kinds, but not of naming
Kripke derives accounts of reference and proper names from assumptions about worlds and essences
19. Language / D. Theories of Reference / 3. Direct Reference / b. Causal reference
We may refer through a causal chain, but still change what is referred to
The important cause is not between dubbing and current use, but between the item and the speaker's information
19. Language / D. Theories of Reference / 3. Direct Reference / c. Social reference
Kripke's theory is important because it gives a collective account of reference
We refer through the community, going back to the original referent
We refer to a man via our connection with a language community, going back to the man himself
A description may fix a reference even when it is not true of its object
19. Language / D. Theories of Reference / 4. Descriptive Reference / a. Sense and reference
Frege's 'sense' is ambiguous, between the meaning of a designator, and how it fixes reference
19. Language / D. Theories of Reference / 4. Descriptive Reference / b. Reference by description
Descriptive reference shows how to refer, how to identify two things, and how to challenge existence
It can be necessary that Aristotle had the properties commonly attributed to him
Even if Gödel didn't produce his theorems, he's still called 'Gödel'
26. Natural Theory / B. Concepts of Nature / 6. Natural Kinds / e. Necessity of kinds
Gold's atomic number might not be 79, but if it is, could non-79 stuff be gold?
'Cats are animals' has turned out to be a necessary truth
26. Natural Theory / B. Concepts of Nature / 6. Natural Kinds / f. Reference to natural kinds
Terms for natural kinds are very close to proper names
The properties that fix reference are contingent, the properties involving meaning are necessary
26. Natural Theory / B. Concepts of Nature / 6. Natural Kinds / g. Critique of kinds
Nominal essence may well be neither necessary nor sufficient for a natural kind
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / b. Scientific necessity
Scientific discoveries about gold are necessary truths
The scientific discovery (if correct) that gold has atomic number 79 is a necessary truth
Once we've found that heat is molecular motion, then that's what it is, in all possible worlds
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / d. Knowing essences
Science searches basic structures in search of essences
27. Natural Reality / C. Biology / 5. Species
Tigers may lack all the properties we originally used to identify them
'Tiger' designates a species, and merely looking like the species is not enough
The original concept of 'cat' comes from paradigmatic instances