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Ideas of Saul A. Kripke, by Text

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

1959 A Completeness Theorem in Modal Logic
p.9 The variable domain approach to quantified modal logic invalidates the Barcan Formula
     Full Idea: Kripke's variable domain approach to quantified modal logic famously invalidates the Barcan Formula.
     From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Ori Simchen - The Barcan Formula and Metaphysics §3
     A reaction: [p.9 and p.16] In a single combined domain all the possibilia must be present, but with variable domains objects in remote domains may not exist in your local domain. BF is committed to those possible objects.
p.256 The Barcan formulas fail in models with varying domains
     Full Idea: Kripke showed that the Barcan formula ∀x□A⊃□∀xA and its converse fail in models which require varying domains.
     From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Timothy Williamson - Truthmakers and Converse Barcan Formula §1
     A reaction: I think this is why I reject the Barcan formulas for metaphysics - because the domain of metaphysics should be seen as varying, since some objects are possible in some contexts and not in others. Hmm…
p.286 Propositional modal logic has been proved to be complete
     Full Idea: At the age of 19 Saul Kripke published a completeness proof of propositional modal logic.
     From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Feferman / Feferman - Alfred Tarski: life and logic Int V
p.315 With possible worlds, S4 and S5 are sound and complete, but S1-S3 are not even sound
     Full Idea: Kripke gave a possible worlds semantics to a whole range of modal logics, and S4 and S5 turned out to be both sound and complete with this semantics. Hence more systems could be designed. S1-S3 failed in soundness, leading to 'impossible worlds'.
     From: report of Saul A. Kripke (A Completeness Theorem in Modal Logic [1959]) by Marcus Rossberg - First-order Logic, 2nd-order, Completeness §4
1970 Naming and Necessity lectures
p.-10 Kripke assumes that mind-brain identity designates rigidly, which it doesn't
     Full Idea: In his attempted disproof of materialism about the mind, Kripke assumes that the physical description is a rigid designator, but this seems to be begging the question against the causal theory, which says the description is non-rigid.
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970]) by David M. Armstrong - Pref to new 'Materialist Theory' p.xiv
     A reaction: A crucial part of this is that Armstrong believes that the laws of nature are contingent, and hence mind-brain identity has to be. Personally I incline to say that the identity is rigid, but that Kripke is still wrong.
p.1 Kripke has breathed new life into the a priori/a posteriori distinction
     Full Idea: The a priori/a posteriori is still taken seriously, and has had new life breathed into it by the work of Saul Kripke.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by E.J. Lowe - The Possibility of Metaphysics 1.1
     A reaction: The distinction may be a good one, despite a blurred borderline. Did Egyptian quantity surveyors begin to suspect that Pythagoras's Theorem was a necessary truth, though they couldn't prove it? A priori understanding creeps into experience.
p.4 Kripke's modal semantics presupposes certain facts about possible worlds
     Full Idea: Kripke's modal semantics presupposes that worlds are maximal and consistent, that there is a unique actual world, and that worlds are coherent (e.g. lack contradiction, obey conjunction).
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Edward N. Zalta - Deriving Kripkean Claims with Abstract Objects
p.9 Kripke's metaphysics (essences, kinds, rigidity) blocks the slide into sociology
     Full Idea: Kripke's metaphysics of essences, natural kinds, and rigid designation gave philosophers a means of avoiding the relativist path that was bound to end in the tears of sociology.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by J Ladyman / D Ross - Every Thing Must Go 1.2
     A reaction: They are contemptuous of Kripke's project, but this is the core of it. He was making a stand against Kuhn, and trying to build a metaphysics for realism. Good for Kripke.
p.30 Some references, such as 'Neptune', have to be fixed by description rather than baptism
     Full Idea: Kripke explicitly allows for the introduction of names through initial reference-fixing via descriptions. Versions of the causal theory of reference that disallow this would have a difficult time explaining how the name 'Neptune' came to refer.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Zoltán Gendler Szabó - Nominalism 4.2 n35
     A reaction: The initial reference to Neptune has to be by description, but you could still give a baptismal account once it is discovered. The direct contact now takes precedence. Suppose another similar planet was found nearby...
p.54 Test for rigidity by inserting into the sentence 'N might not have been N'
     Full Idea: Kripke offers an intuitive test for telling whether a term is rigid: try the term in the sentence-frame "N might not have been N". (For example, try the terms 'Nixon' and 'President of the USA').
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by William Lycan - Philosophy of Language Ch.4
     A reaction: Helpful, but if you try it, the results do not seem to be conclusive. You are left saying 'Well, it depends what you mean by...' Think of possible worlds with a crippled Nixon, twin Nixons, an honest Nixon, a robot Nixon, a dark skinned Nixon...
p.71 Kripke makes reference a largely social matter, external to the mind of the speaker
     Full Idea: Kripke's theory brought a social element into the function of language: a speaker is socially connected to others who may know far more than she does about the reference of her terms, and the mechanism of reference is now not in her mind, but is external.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Colin McGinn - The Making of a Philosopher Ch. 3
     A reaction: Hence this theory of reference leads on to Putnam's 'wide content' and Twin Earth. I remain unconvinced. See ideas under 'Thought'.
p.77 Kripke avoids difficulties of transworld identity by saying it is a decision, not a discovery
     Full Idea: Objects we find in the actual world might have been so different than they actually are that it appears impossible to identify the same objects from world to world. Kripke sidesteps the problem by saying transworld identity is a decision, not a discovery.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Dale Jacquette - Ontology Ch.2
     A reaction: This is the strategy that opposes Lewis's proposal of 'counterpart' objects that have properties in common. It is also the source of Kripke's causal theory of reference, and hence a key to massive modern debates.
p.79 If consciousness could separate from brain, then it cannot be identical with brain
     Full Idea: Kripke's argument is that the possibility of conscious properties coming apart from material properties shows that they cannot be identical with material properties.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by David Papineau - Thinking about Consciousness 3.3
     A reaction: A nice clear and simple summary. How can the possibility of coming apart be demonstrated? Only, it seems, by using our imaginations. But that is quite a good guide in areas we know well, but not in recondite areas like the brain.
p.101 Nominal essence may well be neither necessary nor sufficient for a natural kind
     Full Idea: Kripke's tiger example shows that a nominal essence is not necessary for the existence of a natural kind; examples from Putnam show that a nominal essence is not sufficient either.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Alexander Bird - Philosophy of Science Ch.3
     A reaction: None of the characteristics of a tiger is essential to it. The appearance of water doesn't fix its reference. The move is towards an external view, that what matters for natural kinds is the real essence, not human conventions about it. I agree.
p.119 Kripke separates necessary and a priori, proposing necessary a posteriori and contingent a priori examples
     Full Idea: It is now recognised that the apriori and the necessary don't always have to go together, ..and Kripke has suggested examples of necessary-aposteriori and contingent-apriori beliefs.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Paul O'Grady - Relativism Ch.4
     A reaction: The simple point is that whether something is necessary or contingent is a quite separate question from how we come to know that they are. There isn't a new mode of reality called 'necessary a posteriori'.
p.131 Kripke has demonstrated that some necessary truths are only knowable a posteriori
     Full Idea: Kripke has demonstrated the existence of necessary truths such as "water is H2O" whose necessity is only knowable a posteriori.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by David J.Chalmers - The Conscious Mind 2.4.2
p.132 If we lose track of origin, how do we show we are maintaining a reference?
     Full Idea: Perhaps Kripke's argument for the necessity to a thing of its actual origin is that the speculator has to be able to rebut the charge that he has lost his grasp of his subject of discourse if he conceives of this subject with changed parents or origin.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by David Wiggins - Sameness and Substance Renewed 4.10
     A reaction: On the whole Wiggins opposes necessity of origin (cf. Forbes, who defends it). If this idea is right, then any means of ensuring reference will do the job, and it clearly wouldn't be an argument that guaranteed necessity of origin.
p.133 Kripke argues, of the Queen, that parents of an organism are essentially so
     Full Idea: If we generalise what Kripke says about the Queen, then he is arguing that the parents of any organism are essentially the parents of that organism.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Graeme Forbes - The Metaphysics of Modality 6.1
     A reaction: It strikes me that we have to be extremely careful in specifying what it is that Kripke is saying. I take it that either Kripke is saying something rather uninteresting, or he is saying what Forbes suggests. Parenthood is essential, not just necessary.
p.161 Instead of being regularities, maybe natural laws are the weak a posteriori necessities of Kripke
     Full Idea: By defending a posteriori necessary statements, Kripke introduced the concept of a necessity in nature that was weaker than logical necessity; ..as a result, the dominant view of laws as mere regularities started to be seriously challenged.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Stathis Psillos - Causation and Explanation §6.1
     A reaction: Most of Kripke's examples of discovered necessities seem to be identities, which seem to be as strong as any logical necessity. I'm not sure I can make sense of a 'less strong necessity'. Necessity sounds all-or-nothing to me.
p.161 Saying that natural kinds are 'rigid designators' is the same as saying they are 'indexical'
     Full Idea: Kripke's doctrine that natural kind words are rigid designators and our doctrine that they are indexical are two ways of making the same point.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Hilary Putnam - Meaning and Reference p.161
     A reaction: I think I prefer Putnam's terminology, because it is more modest in its claims Kripke gets into trouble when a natural kind in some other possible world is only subtly different from the original. How 'rigid'? Putnam sticks to how the word gets started.
p.165 Kripke derives accounts of reference and proper names from assumptions about worlds and essences
     Full Idea: One might think that the direction of Kripke's arguments goes the other way - that conclusions about reference and proper names were derived in part from controversial metaphysical assumptions about possible worlds and essential properties.
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970]) by Robert C. Stalnaker - Reference and Necessity Intro
     A reaction: Nathan Salmon is famous for charging Kripke with trying to get a metaphysics from a semantics, but this remark of Stalnaker's seems much more accurate. Kripke certainly assumes realism, and robust identity.
p.167 Kripke's essentialist necessary a posteriori opened the gap between conceivable and really possible
     Full Idea: With Kripke's essentialist route to the necessary a posteriori came a sharp distinction between conceivability and genuine possibility - ways things could conceivably be versus ways things could really be (or have been).
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970]) by Scott Soames - Significance of the Kripkean Nec A Posteriori p.167
     A reaction: A key idea, for me. I love 'could there be a bonfire on the moon?' Imagining it is easy-peasy. 'Could wood combine with oxygen when there is no oxygen present?' We imagined it all right, but did we 'conceive' it?
p.167 Kripke separated semantics from metaphysics, rather than linking them, making the latter independent
     Full Idea: Kripke's contribution was not to connect metaphysical and semantic issues, but to separate them: to provide a context in which questions about essences of things could be posed independently of assumptions about semantic rules of reference.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Robert C. Stalnaker - Reference and Necessity Intro
     A reaction: In other words, Kripke set metaphysics free from the tyranny of Quine, and facilitated its modern rebirth. Bravo.
p.168 Kripke gets to the necessary a posteriori by only allowing conceivability when combined with actuality
     Full Idea: Kripke's first (superior) route to necessary a posteriori has a sharp distinction between how the universe could conceivably and really be. ..On this picture conceivability is a fallible but useful guide, when combined with knowledge of actuality.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Scott Soames - Significance of the Kripkean Nec A Posteriori p.168
     A reaction: [compressed from p.168 and 170] To dismiss conceivability is ridiculous (see Williamson on that), and this formula of Soames sound right. To understand possibility, you have to study actuality (across time and space). Study history!
p.179 For Kripke, essence is origin; for Putnam, essence is properties; for Wiggins, essence is membership of a kind
     Full Idea: Kripke makes the origin of an organism essential to it, according to Putnam the fundamental physical properties of a thing are essential, Wiggins sees an organism's essence in belonging to a particular kind, etc.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Thomas Mautner - Penguin Dictionary of Philosophy p.179
     A reaction: This is helpful for seeing where the problems remain, if you embrace essentialism (as I feel inclined to do). It is vital to remember Putnam's point, that we could suddenly discover that cats are alien robots. This seems to undermine Kripke and Wiggins.
p.180 Kripke claims that some properties, only knowable posteriori, are known a priori to be essential
     Full Idea: Kripke's first (good) route to the necessary a posteriori is based on the idea that certain properties of objects that they can be known to have only a posteriori, may be known a priori to be essential properties of anything that has them.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Scott Soames - Significance of the Kripkean Nec A Posteriori p.180
     A reaction: Interesting, and a key issue. I think this is precisely where I disagree with the Kripkean view of necessities. Logicians want to know a priori what is essential for identity, but scientists want to know what makes things tick. See Kripke on pain.
p.181 An essence is the necessary properties, derived from an intuitive identity, in origin, type and material
     Full Idea: For Kripke an object's essence simply consists of its necessary properties. ...His essential properties of individual objects follow from our intuitions about their identity. ...They are of three sorts: of origin, of sortals, and of material.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Charlotte Witt - Substance and Essence in Aristotle 6 n3
     A reaction: This is because Kripke is only interested in identity, whereas Aristotle is interested in explanation. The sorts are efficient, formal, material. Big Q: could Aristotle's account of essence do all the work that is required of essences by Kripke?
p.187 Kripke was more successful in illuminating necessity than a priority (and their relations to analyticity)
     Full Idea: Kripke was far more successful in illuminating the nature of necessity, and distinguishing it from both apriority and analyticity, than he was in illuminating the nature of apriority, and distinguishing that from analyticity.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Scott Soames - Significance of the Kripkean Nec A Posteriori p.187
p.193 If Kripke names must still denote a thing in a non-actual situation, the statue isn't its clay
     Full Idea: Kripke gives an account of proper names from which it follows that Goliath (the statue) cannot be identical the lumpl (the clay), ..because if a proper name denotes a thing in the actual world, then it denotes that same thing in non-actual situations.
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970]) by Allan Gibbard - Contingent Identity III
     A reaction: This strikes me as a powerful criticism of Kripke's claim - and has led to extensive discussion which I will now have to pursue. Watch this space.
p.203 Kripke's theory is important because it gives a collective account of reference
     Full Idea: What is important about Kripke's theory is not that the use of proper names is 'causal' - what is not? - but that the use of proper names is collective.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Hilary Putnam - Explanation and Reference II B
     A reaction: This is the best response to Kripke. Reference is achieved by thinkers and speakers, but it is also a team activity, as in the case of the elm, or of Amenhotep II.
p.204 The important cause is not between dubbing and current use, but between the item and the speaker's information
     Full Idea: Kripke has mislocated the important causal relation, which lies between the item's states and doings and the speaker's body of information - not between the item's being dubbed with a name and the speaker's contemporary use of it.
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970]) by Gareth Evans - The Causal Theory of Names §I
     A reaction: This feels sort of right. I sympathise with the much more social view of matters like reference, which grows out of Wittgenstein's anti-private language claims. I'm not sure where 'causation' come into Evans's picture.
p.220 Kripke individuates objects by essential modal properties (and presupposes essentialism)
     Full Idea: The difficulty is that Kripke individuates objects by their modal properties, by what they (essentially) could and could not be. Kripke's ontology presupposes essentialism; it can not be used to ground it.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Hilary Putnam - Why there isn't a ready-made world 'Essences'
p.308 Kripke says pain is necessarily pain, but a brain state isn't necessarily painful
     Full Idea: Kripke's argument against mind-brain identity is that a pain is necessarily pain (just as a stone is necessarily matter), but a brain state is not necessarily painful (just as a stone is not necessarily a doorstep).
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Georges Rey - Contemporary Philosophy of Mind 11.6.2
     A reaction: As with Descartes' argument from necessity for dualism, this seems to me to beg the question. It seems to me fairly self-evident that certain brain states have to be painful, just as stones always have to be hard or massive.
p.332 Kripke says internal structure fixes species; I say it is genetic affinity and a common descent
     Full Idea: Kripke stresses that membership of a single animal species requires identity or similarity of internal structure. In my view, what matters is genetic affinity - a common descent. Internal structure is merely a clue.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Michael Dummett - Could There Be Unicorns? 2
     A reaction: The crucial test question would be whether we can make a tiger artificially (even constructing the DNA). I would say that if you make a tiger, that's a tiger, so Kripke is right and Dummett is wrong. The species is what it is, not where it came from.
p.374 Kripke has a definitional account of kinds, but not of naming
     Full Idea: There seems to be an incongruity between Kripke's definitionalist account of the essence of kinds (and the induced necessities), and his definition-free account of naming.
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970]) by Joseph Almog - Nature Without Essence X
     A reaction: Putnam places more emphasis on baptising a prototypical example, just as we baptise named things.
p.399 Proper names must have referents, because they are not descriptive
     Full Idea: A common source of the view that proper names must have referents is that they are not descriptive (as expressed by Kripke).
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Mark Sainsbury - The Essence of Reference 18.2
     A reaction: Sainsbury observes that there might be some other way for a name to be intelligible, with describing or referring.
p.416 A rigid expression may refer at a world to an object not existing in that world
     Full Idea: In the Kripkean perspective, rigidity is understood in such a way that an expression may have as referent at a world an object which does not exist at that world.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Mark Sainsbury - The Essence of Reference 18.6
     A reaction: This means that 'the present King of France' is a rigid designator.
p.418 Names are rigid, making them unlike definite descriptions
     Full Idea: It was important to Kripke to contrast the rigidity of names with the non-rigidity of many or most definite descriptions.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970]) by Mark Sainsbury - The Essence of Reference 18.6
     A reaction: Philosophers always want sharp distinctions, but there are tricky names like 'Homer' and 'Jack the Ripper' where the name is stable, but its referent wobbles.
159 p.9 Kripke says his necessary a posteriori examples are known a priori to be necessary
     Full Idea: Kripke claims that all of his examples of the necessary a posteriori have the characteristic that we can know a priori that if they are true, they are necessarily true.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970], 159) by Penelope Mackie - How Things Might Have Been 1.4
     A reaction: That is, it seems, that they are not really necessary a posteriori! The necessity seems to only arrive with the addition of a priori judgements, thus endorsing the traditional view that necessity is only derivable a priori. Hm.
Lecture 1 p.24 That there might have been unicorns is false; we don't know the circumstances for unicorns
     Full Idea: I think it is not the case that there might have been unicorns. I wouldn't say it is necessary that there are no unicorns, but that we just can't say under what circumstances there would have been unicorns.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: His point seems to be that unicorns are insufficiently individuated by the legends, whereas a typical sample of an actual creature contains everything that will individuate the species.
Lecture 1 p.28 Descriptive reference shows how to refer, how to identify two things, and how to challenge existence
     Full Idea: Summary: in favour of the descriptive theory of names are it gives you a mechanism for doing the referring (and Mill doesn't), we can identify two descriptions if there is one referent, and it allows us to question the existence of a referent.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1) by PG - Db (ideas)
     A reaction: If this problem is seen in terms of mental files (with labels and contents) this whole problem becomes a lot clearer. I take reference to be the action of a thinker, not a function of language.
Lecture 1 p.34 Rather than 'a priori truth', it is best to stick to whether some person knows it on a priori evidence
     Full Idea: A priori is supposed to mean something which can be known independently of experience, …but possible for whom? God, or the Martians? …Instead of 'a priori truth' it is best to stick to whether some person knows it based on a priori evidence.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: [compressed] This is Kripke's famous attempt to establish that 'a priori' is strictly an epistemological term, and should not be taken as a term of metaphysics (or modal semantics?). I definitely prefer the Kripke view, though it downgrades the a priori.
Lecture 1 p.34 A priori truths can be known independently of experience - but they don't have to be
     Full Idea: The traditional characterisation (since Kant) goes: a priori truths are those which can be known independently of any experience - ..but that doesn't mean they MUST be known a priori.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: You may discover through experience that nine matches can't be divided into two equal piles, but Leibniz (and others) say you will only see the necessity of this a priori. No necessity is visible in the matches.
Lecture 1 p.38 A priori = Necessary because we imagine all worlds, and we know without looking at actuality?
     Full Idea: People think 'necessary' and 'a priori' mean the same for two reasons: we can assess what is feasible in all possible world by running them through our heads, and something known a priori avoids looking at the world, so it must be necessary.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: [compressed] Kripke denies this doctrine, and pulls the concepts apart. Kant seems to be the chief representative of the view he is attacking. Hossack defends the older view.
Lecture 1 p.42 Intuition is the strongest possible evidence one can have about anything
     Full Idea: I think something's having intuitive content is very heavy evidence in favour of it. I really don't know what more conclusive evidence one can have about anything, ultimately speaking.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: This seems to me a very appealing remark, especially coming from a great logician. It seems to me, though, that some intuitions are more rational than others, and we must occasionally give up intuitions that are proved wrong.
Lecture 1 p.43 No one seems to know the identity conditions for a material object (or for people) over time
     Full Idea: Adequate necessary and sufficient conditions for identity which do not beg the question are very rare. …I don't know of such conditions for identity of material objects over time, or for people. Everyone knows what a problem this is.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: Typical of Kripke, who only seems to commit to conclusions suggested to him by his modal logic, and is baffled by almost everything else. I think one can at least attempt an essentialist approach to this problem.
Lecture 1 p.44 Possible worlds aren't puzzling places to learn about, but places we ourselves describe
     Full Idea: A possible world isn't a distant country that we are coming across, or viewing through a telescope. …A possible world is given by the descriptive conditions we associate with it. …Possible worlds are stipulated, not discovered by powerful telescopes.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: His point is that it is absurd to be puzzling over the identity of what exists in some possible world, because the world is specified by us. If I say 'Nixon might have been a frog', I must be referring to Nixon. The problem is whether it is true.
Lecture 1 p.44 If we discuss what might have happened to Nixon, we stipulate that it is about Nixon
     Full Idea: There is no reason why we cannot stipulate that, in talking about what would have happened to Nixon in a certain counterfactual situation, we are talking about what would have happened to HIM.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: For many people (including me now, I think) this lays to rest the supposed problem of 'transworld identity' wrestled with by Kaplan and Lewis.
Lecture 1 p.47 Given that Nixon is indeed a human being, that he might not have been does not concern knowledge
     Full Idea: Suppose Nixon actually turned out to be an automaton. That might happen. But that is a question about our knowledge. The question of whether he might not have been a human being, given that he is one, is not a question about knowledge.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: Given that you are sitting, might you be standing? Yes. Given that you are human, might you be non-human? No. Maybe!
Lecture 1 p.47 Given that a table is made of molecules, could it not be molecular and still be this table?
     Full Idea: This table is composed of molecules. …Could anything be this very object and not be composed of molecules? …It's hard to imagine under what circumstances you would have this very object and find that it is not composed of molecules.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: This is the thesis of essentiality of constitution. Given that it is square, might it have been round? Yes. Given that it is wood, might it have been metal? No? Given that it is molecular, might it have been plasma? No. ….Maybe.
Lecture 1 p.48 An essential property is true of an object in any case where it would have existed
     Full Idea: When we think of a property as essential to an object we usually mean that it is true of that object in any case where it would have existed.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: This seems to equate essence with necessary properties, which is the view attacked nicely be Fine in 1994. I take essence (in Aristotle's sense) to be quite different from necessary properties (in being non-trivial, for example).
Lecture 1 p.48 Names are rigid designators, which designate the same object in all possible worlds
     Full Idea: I will call something a 'rigid designator' if in every possible world it designates the same object, ..and I will maintain the intuitive thesis that names are rigid designators.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: The immediate problem seems to be objects that change across possible worlds. Did nature rigidly designate Aristotle (e.g. by his DNA)? Could Aristotle have been shorter, female, cleverer, his own twin? Is the River Thames rigid?
Lecture 1 p.49 Transworld identification is unproblematic, because we stipulate that we rigidly refer to something
     Full Idea: It is because we refer (rigidly) to Nixon, and stipulate that we are speaking of what might have happened to him (under certain circumstances), that 'transworld identifications' are unproblematic in such cases.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: This responds to those who say you need transworld identification before you can rigidly designate something, which has 'reversed the cart and horse' says Kripke. Nice.
Lecture 1 p.52 A table in some possible world should not even be identified by its essential properties
     Full Idea: A table should not be identified with the set or 'bundle' of its properties, nor with the subset of its essential properties. Don't ask: how can I identify this table in another possible world, except by its properties? I have the table in my hands.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: You identify the table by what's in front of you, but the essence might be relevant to deciding how far this table could change and remain this table.
Lecture 1 p.52 A bundle of qualities is a collection of abstractions, so it can't be a particular
     Full Idea: I deny that a particular is nothing but a 'bundle of qualities', whatever that may mean. If a quality is an abstract object, a bundle of qualities is an object of an even higher degree of abstraction, not a particular.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: Supports the 'baptism' view of reference, rather than Searle's bundle of descriptions. It shows that theories of reference must tie in with theories of universals, and that Searle is a nominalist. Is Kripke trying to duck metaphysical responsibility?
Lecture 1 p.53 Identification across possible worlds does not need properties, even essential ones
     Full Idea: Some properties of an object may be essential to it, in that it could not have failed to have them. But these properties are not used to identify the object in another possible world, for such an identification is not needed.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: So how DO you identify objects in other possible worlds, or in this one? You may say he was baptised 'Aristotle' so that's rigid, but if Athens is full of pseudo-Aristotles I want to pick out the real one. I say Kripke muddles epistemology and ontology.
Lecture 1 p.53 We do not begin with possible worlds and place objects in them; we begin with objects in the real world
     Full Idea: We do not begin with worlds (which are supposed somehow to be real), and then ask about criteria of transworld identification; on the contrary, we begin with objects, which we have, and can identify, in the real world.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: This gives us clearly Kripke's underlying empiricist metaphysics, I take it. I find the realism of it appealing, but am uneasy about the idea of an object as basic, when Heraclitus said that they tend to fluctuate. Platonism waits in the wings.
Lecture 1 p.56 The meter is defined necessarily, but the stick being one meter long is contingent a priori
     Full Idea: In 'one meter is the length of stick S at t', one designator (one meter) is rigid and the other (length of S at t) is not. 'S is one meter long at t' is contingent, as it could have a different length. In this sense, there are contingent a priori truths.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: [very compressed] Not convincing. He is proposing that a truth is knowable a priori, though knowledge of it is utterly dependent on a ceremony having taken place. It would not be true if that event hadn't taken place, so how can be it be known a priori?
Lecture 1 p.60 Some definitions aim to fix a reference rather than give a meaning
     Full Idea: Some things called definitions really intend to fix a reference rather than to give the meaning of a phrase, to give a synonym.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 1)
     A reaction: His example is pi. Some definitions relate to reality (e.g. ostensive definition), and others are part of a language game. But then some concepts are dictated to us by reality, and others are arbitrarily invented by us for convenience.
Lecture 2 p.74 It can't be necessary that Aristotle had the properties commonly attributed to him
     Full Idea: It is just not, in any intuitive sense of necessity, a necessary truth that Aristotle had the properties commonly attributed to him.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: This replies to Searle's claim that to be Aristotle he must have a fair number of the properties. Even if Searle is right, you can hardly pick the properties out individually and claim they are necessary. Kripke pulls epistemology away from metaphysics.
Lecture 2 p.77 Important properties of an object need not be essential to it
     Full Idea: Important properties of an object need not be essential, unless 'importance' is used as a synonym for essence.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: Kripke's examples are the writings of Aristotle and the actions of Hitler, but these don't strike me as being 'properties' of those people. They are not intrinsic. Kripke, of course, is concerned with how we identify them, not who they actually are.
Lecture 2 p.86 A name can still refer even if it satisfies none of its well-known descriptions
     Full Idea: Suppose the vote yields no object, that nothing satisfies most, or even any, substantial number, of the φ's. Does that mean the name doesn't refer? No.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: As example he gives the case of 'Gödel' referring to the famous man, even if none of the descriptions of him are true. In Note 42 he blames the descriptivists for relying too much on famous people.
Lecture 2 p.93 We may refer through a causal chain, but still change what is referred to
     Full Idea: There may be a causal chain from our use of the term 'Santa Claus' to a certain historical saint, but still children, when they use this, by this time probably do not refer to that saint.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: This is quite a significant concession to critics of the causal theory. I take it that community agreement is much more significant for reference than the actual causal chain, which may be riddled with errors from beginning to end, and so isn't causal.
Lecture 2 p.94 We refer through the community, going back to the original referent
     Full Idea: It's in virtue of our connection with other speakers in the community, going back to the referent himself, that we refer to a certain man.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: There may be two theories of reference getting tangled up here. Going back to the origin is one thing, and relying on the community is another. Do I always know who I am referring to? 'The funniest man in London'.
Lecture 2 p.94 Analyses of concepts using entirely different terms are very inclined to fail
     Full Idea: Philosophical analyses of some concept like reference, in completely different terms which make no mention of reference, are very apt to fail.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: Kripke consistently criticises analysic, and philosophical 'theories'. It is why he wanted a 'direct' theory of reference, with just you and the object.
Lecture 2 p.98 Identity statements can be contingent if they rely on descriptions
     Full Idea: If the man who invented bifocals was the first Postmaster General of the United States - that they were one and the same - it's contingently true. …So when you make identity statements using descriptions, that can be a contingent fact.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
Lecture 2 p.99 Physical necessity may be necessity in the highest degree
     Full Idea: Physical necessity might turn out to be necessity in the highest degree. But that's a question which I don't wish to prejudge.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: Presumably necessity 'in the highest degree' is 'metaphysical' necessity, but Kripke is a bit coy about that. This is the germ of modern scientific essentialism.
Lecture 2 p.99 Identities like 'heat is molecule motion' are necessary (in the highest degree), not contingent
     Full Idea: I hold that characteristic theoretical identifications like 'heat is the motion of molecules', are not contingent truths but necessary truths, and I don't just mean physically necessary, but necessary in the highest degree.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: This helps to keep epistemology and ontology separate. The contingency was in the epistemology. That the identity is 'physically necessary' seems obvious; that it is necessary 'in the highest degrees' implies an essentialist view of nature.
Lecture 2 p.104 If Hesperus and Phosophorus are the same, they can't possibly be different
     Full Idea: If Hesperus and Phosphorus are one and the same, then in no other possible world can they be different.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 2)
     A reaction: If we ask whether one object could possibly be two objects, and deny that possibility, then Kripke's novel thought seems just right and obvious.
Lecture 3 p.35 Identity must be necessary, but pain isn't necessarily a brain state, so they aren't identical
     Full Idea: The identity theorist, it appears, can admit that the identity is necessary if true without substantially altering his position, but Kripke argues that the identity between pain and some brain states is not necessary.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3) by Stephen P. Schwartz - Intro to Naming,Necessity and Natural Kinds §IV
     A reaction: This appears to depend on being able to imagine the pain occurring with a different brain state, or no brain state. Bad argument. See Idea 5819.
Lecture 3 p.106 A name's reference is not fixed by any marks or properties of the referent
     Full Idea: It is in general not the case that the reference of a name is determined by some uniquely identifying marks, some unique properties satisfied by the referent and known or believed to be true of that referent by the speaker.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: He is proposing, instead, his historical/causal theory. There does seem to be a problem with objects which have a historical 'baptism', and then entirely change their properties. Kripke us desperate for a simple account of reference.
Lecture 3 p.108 "'Hesperus' is 'Phosphorus'" is necessarily true, if it is true, but not known a priori
     Full Idea: An identity statement between names (such as 'Hesperus' and 'Phosphorus'), when true at all, is necessarily true, even though one may not know it a priori.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: This seems correct, but one should not read too much into it. What should we say if Venus fissions into two, one for the morning, one for the evening? That identity implies x=x doesn't prove the existence of unchanging essences.
Lecture 3 p.110 De re modality is an object having essential properties
     Full Idea: De re modality is an object having essential properties.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: [Plucked out of context] It is because Kripke says there are necessities about things, and not just about statements about things, that he has caused a revival of essentialism. Fine has famously said modality depends on essence.
Lecture 3 p.112 Could the actual Queen have been born of different parents?
     Full Idea: Could the Queen - could this woman herself - have been born of different parents from the parents from whom she actually came?
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: Tricky! No, because the past is fixed? Could the Queen have visited Russia when she was 20? I suppose so. Might she not have had parents, given who she is? I don't see why not. Could this desk have been made by someone else? Why not?
Lecture 3 p.113 It is a necessary truth that Elizabeth II was the child of two particular parents
     Full Idea: How could a person originating from different parents, from a totally different sperm and egg, be this very woman (Elizabeth II)? ..It seems to me that anything coming from a different origin would not be this very object.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: Since baby Elizabeth could have been smuggled into the palace in a bedpan, it seems to me that her properties now are rather more obvious than her origin. I fear the only necessity here is that you can't change the past. An intriguing puzzle.
Lecture 3 p.114 If we imagine this table made of ice or different wood, we are imagining a different table
     Full Idea: Though we can imagine a table identical to this one in this room, but made of ice (or different wood), it seems to me that this is not to imagine this table as made of ice, but to imagine another table, resembling this one, made of ice.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: This is the Necessity of Constitution thesis, which I doubt. Might this table have had one leg different? Why not? Then you have a Ship of Theseus question. How much could be different? How much of the constitution is necessary?
Lecture 3 p.117 Analytic judgements are a priori, even when their content is empirical
     Full Idea: All analytic judgements are a priori even when the concepts are empirical, as, for example, 'Gold is a yellow metal'; for to know this I require no experience beyond my concept of gold as a yellow metal.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: So I relate a priori to 'turquoise is a shade of red', even though my concepts are confused? It is my concept, perhaps, but it is false. I thought a priori had something to do with knowing, not with reporting the confused nonsense in my mind?
Lecture 3 p.121 Tigers may lack all the properties we originally used to identify them
     Full Idea: We might find out that tigers had none of the properties by which we originally identified them.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: This sounds like a can of worms. If I baptise someone 'the tallest man in the room', and it turns out he isn't, I withdraw my baptism. Why would I never withdraw 'tiger'? I suppose Kripke is right.
Lecture 3 p.121 'Tiger' designates a species, and merely looking like the species is not enough
     Full Idea: We can say in advance that we use the term 'tiger' to designate a species, and that anything not of this species, even though it looks like a tiger, is not in fact a tiger.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: This is the 'baptismal' direct reference theory applied to species as well as to particular names. It seem to hinge on an internal structure being baptised, despite ignorance of what that structure is. Cf nominal essence? 'Tiger' denotes their essence?
Lecture 3 p.122 The original concept of 'cat' comes from paradigmatic instances
     Full Idea: The original concept of cat is: that kind of thing, where the kind can be identified by paradigmatic instances.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: Kripke evokes Putnam at this point, since he is famous for this proposal. Note that Kripke uses the plural, invoking more than one instance. Presumably we must abstract the fur colours from the instances?
Lecture 3 p.123 Gold's atomic number might not be 79, but if it is, could non-79 stuff be gold?
     Full Idea: Gold could turn out not to have atomic number 79. …But given that gold does have the atomic number 79, could something be gold without having the atomic number 79?
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: The question seems to be 'is atomic number 79 essential to gold?', and on p.124 Kripke seems to say 'yes'. I agree. But how do we decide which features are essential to gold? Why do we think molten gold does count as gold?
Lecture 3 p.125 The scientific discovery (if correct) that gold has atomic number 79 is a necessary truth
     Full Idea: Scientific discoveries about what gold is are not contingent truths, but are necessary truths in the strictest possible sense. ..If scientists are right, then it will be necessary and not contingent that gold be an element with atomic number 79.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: I think this glorious and controversial claim is correct. It is hard to find supporting arguments, but the picture of nature that emerges (where the essences of the stuffs precede the laws of their behaviour) seems to me far more coherent.
Lecture 3 p.125 Scientific discoveries about gold are necessary truths
     Full Idea: Statement representing scientific discoveries about what this stuff (gold) is are not contingent truths but necessary truths in the strictest possible sense.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: People take him to mean 'metaphysically necessary' here. How do we distinguish the 'scientific' discoveries, which are necessary, from the more casual discoveries, which may not be? Presumably being yellow is also necessary?
Lecture 3 p.125 Atomic number 79 is part of the nature of the gold we know
     Full Idea: It is part of the nature of gold as we have it to be an element with atomic number 79.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: The word 'nature' directly invokes Aristotle's concept of an essence. Scientific essentialism arises from the idea that by discovering the atomic number, we have somehow 'arrived' at the essence, and enquiry is reaching its terminus.
Lecture 3 p.127 Terms for natural kinds are very close to proper names
     Full Idea: According to the view I advocate, terms for natural kinds are much closer to proper names than is ordinarily supposed. …'Common name' is appropriate for species …and also for certain mass terms such as 'gold' and 'water'.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
Lecture 3 p.133 Once we've found that heat is molecular motion, then that's what it is, in all possible worlds
     Full Idea: We have discovered a phenomenon (heat) which in all possible worlds will be molecular motion - which could not have failed to be molecular motion, because that's what the phenomenon is.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: He refers to the identification as an 'essential property' of the phenomenon (and not merely a necessity). For my taste, Kripke uses the word 'property' too widely.
Lecture 3 p.135 The properties that fix reference are contingent, the properties involving meaning are necessary
     Full Idea: Bear in mind the contrast between the a priori but perhaps contingent properties carried with a natural kind term, given by the way its reference was fixed, and the analytic (and hence necessary) properties a term may carry, given by its meaning.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: The second half of this is the 'new essentialism'. Complex. We need to distinguish 'reference' from 'definition'. The 'analytic properties' seem to be the definition, but we sometimes change our definitions (e.g. of units of time).
Lecture 3 p.138 'Cats are animals' has turned out to be a necessary truth
     Full Idea: 'Cats are animals' has turned out to be a necessary truth.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: False! As Putnam has pointed out, we could yet discover that cats are subtly designed alien robots. This is a revealing error by Kripke, showing his desire to move from a useful logical clarification to an excessively amibitious metaphysics.
Lecture 3 p.138 Science searches basic structures in search of essences
     Full Idea: Science attempts, by investigating basic structural traits, to find the nature, and thus the essence (in the philosophical sense) of the kind.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: The 'necessity' of essences should be treated with caution, but this account of science strikes me as right, with the inbuilt assumption that the 'laws' are the consequence of the essences. A regularity becomes a law when it is explained by an essence.
Lecture 3 p.140 Theoretical identities are between rigid designators, and so are necessary a posteriori
     Full Idea: Theoretical identities, according to the conception I advocate, are generally identities involving rigid designators and therefore are examples of the necessary a posteriori.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: This doesn't open up a huge new realm of a posteriori necessity. We just cured some of our ignorance. I remain unconvinced that the Morning Star is necessarily the Evening Star, except in the boring way that if it is, it is. Venus could fission.
Lecture 3 p.146 It seems logically possible to have the pain brain state without the actual pain
     Full Idea: Prima facie, it would seem that it is a least logically possible the brain state corresponding to pain should have existed (Jones's brain could have been in exactly that state at the time in question) without Jones feeling any pain at all.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: This is Kripke's commitment to the possibility of zombies, which are only possible if the mind-body connection is a contingent one, and he shows that there are no contingent 'identities'. The answer is necessary identity, and no zombies.
Lecture 3 p.149 Identity theorists seem committed to no-brain-event-no-pain, and vice versa, which seems wrong
     Full Idea: The identity theorist is committed to the view that there could not be a C-fibre stimulation which was not a pain, nor a pain which was not a C-fibre stimulation; these consequences are certainly surprising and counterintuitive.
     From: Saul A. Kripke (Naming and Necessity lectures [1970], Lecture 3)
     A reaction: If Kripke saw a glow in an area of his brain every time he felt a pain, he would cease to find it 'counterintuitive'. Far from this conclusion being 'surprising', its opposite is absurd. Pain with no brain event? C-fibres blaze away, and I feel nothing?
p.110- p.152 Socrates can't have a necessary origin, because he might have had no 'origin'
     Full Idea: Against Kripke's thesis of 'necessity of origin' I will just point out the intuitive force of the claim that Socrates - that very person - could, logically, have had no beginning to his existence at all, or have come into existence ex nihilo.
     From: comment on Saul A. Kripke (Naming and Necessity lectures [1970], p.110-) by E.J. Lowe - The Possibility of Metaphysics 6.5
     A reaction: It also strikes me that one base-pair difference in his DNA (by a mutation, or a fractionally different parent) would still leave him as Socrates. People are not good candidates for 'rigid' designation. Counterparts seems a better account here.
p.143-4 p.1 Rigid designation creates a puzzle - why do some necessary truths appear to be contingent?
     Full Idea: Kripke's proposal that referential expressions like indexicals, demonstratives, proper names and natural kind terms are de jure rigid designators created a puzzle - it entails 'modal illusions', truths that are in fact necessary appear to be contingent.
     From: report of Saul A. Kripke (Naming and Necessity lectures [1970], p.143-4) by Maciŕ/Garcia-Carpentiro - Introduction to 'Two-Dimensional Semantics' 1
     A reaction: They are identifying this puzzle as the source of the need for two-dimensional semantics. Kripke notes that rigid designators may have their reference fixed by non-rigid descriptions.
1971 Identity and Necessity
p.172 A 'rigid designator' designates the same object in all possible worlds
     Full Idea: By 'rigid designator' I mean a term that designates the same object in all possible worlds.
     From: Saul A. Kripke (Identity and Necessity [1971])
     A reaction: I am persistently troubled by the case of objects which are slightly different in another possible world. Does 'Aristotle' refer to him as young or old? Might the very same man have had a mole on his cheek?
p.167 p.167 The function of names is simply to refer
     Full Idea: The function of names is simply to refer.
     From: Saul A. Kripke (Identity and Necessity [1971], p.167)
     A reaction: This is Kripke reverting to the John Stuart Mill view of names. If I say "you are a right Casanova" I don't simply refer to Casanova. In notorious examples like 'Homer' reference is fine, but the object of reference is a bit elusive.
p.176 p.176 We cannot say that Nixon might have been a different man from the one he actually was
     Full Idea: It seems that we cannot say "Nixon might have been a different man from the man he in fact was", unless we mean it metaphorically. He might have been a different sort of person.
     From: Saul A. Kripke (Identity and Necessity [1971], p.176)
     A reaction: The problem is that being a 'different sort of person' could become more and more drastic, till Nixon is unrecognisable. I don't see how I can stipulate that a small and dim mouse is Richard Nixon, even in a possible world with magicians.
p.180 p.180 It is necessary that this table is not made of ice, but we don't know it a priori
     Full Idea: Although the statement that this table (if it exists at all) was not made of ice, is necessary, it certainly is not something that we know a priori.
     From: Saul A. Kripke (Identity and Necessity [1971], p.180)
     A reaction: One of the key thoughts in modern philosophy. Kit Fine warns against treating it as a new and exciting toy, but it is a new and exciting toy. Scientific essentialism, which I so want to be true, is built on this proposal.
p.183 p.183 We may fix the reference of 'Cicero' by a description, but thereafter the name is rigid
     Full Idea: We may fix the reference of 'Cicero' by use of some descriptive phrase, such as 'author of these works'. But once we have this reference fixed, we then use the name 'Cicero' rigidly to designate the man who in fact we have identified by his authorship.
     From: Saul A. Kripke (Identity and Necessity [1971], p.183)
     A reaction: Even supposedly rigid names can shift reference, as Evans's example of 'Madagascar' shows (Idea 9041). Reference is a much more social activity than Kripke is willing to admit. There is a 'tradition' of reference (Dummett) for the name 'Cicero'.
p.184 n16 p.184 Modal statements about this table never refer to counterparts; that confuses epistemology and metaphysics
     Full Idea: Statements about the modal properties of this table never refer to counterparts. However, if someone confuses the epistemological problems and the metaphysical problems he will be well on the way to the counterpart theory of Lewis.
     From: Saul A. Kripke (Identity and Necessity [1971], p.184 n16)
     A reaction: I can't make out what we should say about a possible object which is very nearly this table. Kripke needs the table to have a clear and unwavering essence, but tables are not that sort of thing. How would Kripke define 'physical object'?
p.190 p.190 Identity theorists must deny that pains can be imagined without brain states
     Full Idea: The identity theorist has to hold that we are under some illusion in thinking that we can imagine that there could have been pains without brain states.
     From: Saul A. Kripke (Identity and Necessity [1971], p.190)
     A reaction: The origin of Robert Kirk's idea that there might be zombies. Kripke is wrong. Of course Kripke and his friends can imagine disembodied pains; the question is whether being able to imagine them makes them possible, which it doesn't.
p.190 n19 p.190 Pain, unlike heat, is picked out by an essential property
     Full Idea: 'Heat' is a rigid designator, which is picked out by the contingent property of being felt in a certain way; pain, on the other hand, is picked out by an essential (indeed necessary and sufficient) property.
     From: Saul A. Kripke (Identity and Necessity [1971], p.190 n19)
     A reaction: Hm. I could pick out your pain by your contingent whimpering behaviour. I can spot my own potential pain by a combination of bodily damage and pain killing tablets. I suspect him of the same blunder as Descartes on this one.
1972 Naming and Necessity notes and addenda
Add (a) p.157 Unicorns are vague, so no actual or possible creature could count as a unicorn
     Full Idea: If the unicorn myth is supposed to be a particular species, with insufficient internal structure to determine it uniquely, then there is no actual or possible species of which we can say that it would have been the species of unicorns.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], Add (a))
     A reaction: Dummett and Rumfitt discuss this proposal elsewhere.
Add (g) p.164 What many people consider merely physically necessary I consider completely necessary
     Full Idea: My third lecture suggests that a good deal of what contemporary philosophy regards as mere physical necessity is actually necessary tout court.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], Add (g))
     A reaction: He avoids the term 'metaphysically necessary', which most people would not use for this point.
Add (g) p.164 What is often held to be mere physical necessity is actually metaphysical necessity
     Full Idea: My third lecture suggests that a good deal of what contemporary philosophy regards as mere physical necessity is actually necessary 'tout court'.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], Add (g))
     A reaction: This huge claim rides in on the back of Kripke's very useful clarifications. It is the 'new essentialism', and seems to me untenable in this form. There is no answer to Hume's request for evidence of necessity. Why can't essences (and laws) change?
note 12 p.198 The best known objection to counterparts is Kripke's, that Humphrey doesn't care if his counterpart wins
     Full Idea: The most famous objection to counterparts is Kripke's objection that Hubert Humphrey wouldn't care if he thought that his counterpart might have won the 1972 election. He wishes that he had won it.
     From: report of Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 12) by Theodore Sider - Reductive Theories of Modality 3.10
     A reaction: Like Sider, I find this unconvincing. If there is a world in which I don't exist, but my very close counterpart does (say exactly me, but with a finger missing), I am likely to care more about such a person than about complete strangers.
note 15 p.48 Possible worlds are useful in set theory, but can be very misleading elsewhere
     Full Idea: The apparatus of possible worlds has (I hope) been very useful as far as the set-theoretic model-theory of quantified modal logic is concerned, but has encouraged philosophical pseudo-problems and misleading pictures.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 15)
     A reaction: This is presumably a swipe at David Lewis, who claims possible worlds are real. The fact that the originator of possible worlds sees them as unproblematic doesn't mean they are. Fine if they are a game, but if they assert truth, they need a metaphysics.
note 18 p.51 A vague identity may seem intransitive, and we might want to talk of 'counterparts'
     Full Idea: When the identity relation is vague, it may seem intransitive; a claim of apparent identity may yield an apparent non-identity. Some sort of 'counterpart' notion may have some utility here.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 18)
     A reaction: He firmly rejects the full Lewis apparatus of counterparts. The idea would be that a river at different times had counterpart relations, not strict identity. I like the word 'same' for this situation. Most worldly 'identity' is intransitive.
note 18 p.51 We might fix identities for small particulars, but it is utopian to hope for such things
     Full Idea: Maybe strict identity only applies to the particulars (the molecules) in a case of vague identity. …It seems, however, utopian to suppose that we will ever reach a level of ultimate, basic particulars for which identity relations are never vague.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 18)
     A reaction: I agree with this. Ladyman and Ross laugh at the unscientific picture found in dreams of 'simples'.
note 22 p.60 Kaplan's 'Dthat' is a useful operator for transforming a description into a rigid designation
     Full Idea: It is useful to have an operator which transforms each description into a term which rigidly designates the object actually satisfying the description. David Kaplan has proposed such an operator and calls it 'Dthat'.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 22)
note 34 p.80 A description may fix a reference even when it is not true of its object
     Full Idea: In some cases an object may be identified, and the reference of a name fixed, using a description which may turn out to be false of its object.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 34)
     A reaction: This is clearly possible. Someone could be identified as 'the criminal' when they were actually innocent. Nevertheless, how do you remember which person was baptised 'Aristotle' if you don't hang on to a description, even a false one?
note 37 p.87 Even if Gödel didn't produce his theorems, he's still called 'Gödel'
     Full Idea: If a Gödelian fraud were exposed, Gödel would no longer be called 'the author of the incompleteness theorem', but he would still be called 'Gödel'. The description, therefore, does not abbreviate the name.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 37)
     A reaction: Clearly we can't make the description a necessary fact about Gödel, but that doesn't invalidate the idea that successful reference needs some description. E.g. Gödel is a person.
note 50 p.109 A relation can clearly be reflexive, and identity is the smallest reflexive relation
     Full Idea: Some philosophers have thought that a relation, being essentially two-termed, cannot hold between a thing and itself. This position is plainly absurd ('he is his own worst enemy'). Identity is nothing but the smallest reflexive relation.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 50)
     A reaction: I have no idea what 'smallest' means here. I can't be 'to the left of myself', so not all of my relations can be reflexive. I just don't understand what it means to say something is 'identical with itself'. You've got the thing - what have you added?
note 56 p.134 A different piece of wood could have been used for that table; constitution isn't identity
     Full Idea: Could the artificer not, when he made the table, have taken other pieces? Surely he could. [n37: I venture to think that Kripke's argument in note 56 for the necessity of constitution depends on treating constitution as if it were identity].
     From: comment on Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 56) by David Wiggins - Sameness and Substance Renewed 4.11
     A reaction: Suppose the craftsman completed the table, then changed a piece of wood in it for some reason. Has he now made a second table and destroyed the first one? Wiggins seems to be right.
note 63 p.122 The a priori analytic truths involving fixing of reference are contingent
     Full Idea: If statements whose a priori truth is known via the fixing of a reference are counted as analytic, then some analytic truths are contingent.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 63)
note 77 p.155 I regard the mind-body problem as wide open, and extremely confusing
     Full Idea: I regard the mind-body problem as wide open, and extremely confusing.
     From: Saul A. Kripke (Naming and Necessity notes and addenda [1972], note 77)
     A reaction: Kripke opposes reductive physicalism, but is NOT committed to dualism. He seems to be drawn to Davidson or Nagel (see his note 73). I think his discussion of contingent mind-brain identity is confused.
1975 Outline of a Theory of Truth
p.6 Kripke's semantic theory has actually inspired promising axiomatic theories
     Full Idea: Kripke has a semantic theory of truth which has inspired promising axiomatic theories of truth.
     From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Leon Horsten - The Tarskian Turn 01.2
     A reaction: Feferman produced an axiomatic version of Kripke's semantic theory.
p.20 Kripke offers a semantic theory of truth (involving models)
     Full Idea: One of the most popular semantic theories of truth is Kripke's theory. It describes a class of models which themselves involve a truth predicate (unlike Tarski's semantic theory).
     From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Leon Horsten - The Tarskian Turn 02.3
     A reaction: The modern versions explored by Horsten are syntactic versions of this, derived from Feferman's axiomatisation of the Kripke theory.
p.94 Certain three-valued languages can contain their own truth predicates
     Full Idea: Kripke showed via a fixed-point argument that certain three-valued languages can contain their own truth predicates.
     From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Anil Gupta - Truth
     A reaction: [Gupta also cites Martin and Woodruff 1975] It is an odd paradox that truth can only be included if one adds a truth-value of 'neither true nor false'. The proposed three-valued system is 'strong Kleene logic'.
p.210 Kripke classified fixed points, and illuminated their use for clarifications
     Full Idea: Kripke's main contribution was …his classification of the different consistent fixed points and the discussion of their use for discriminating between ungrounded sentences, paradoxical sentences, and so on.
     From: report of Saul A. Kripke (Outline of a Theory of Truth [1975]) by Volker Halbach - Axiomatic Theories of Truth 15.1
5.1 p.93 The Tarskian move to a metalanguage may not be essential for truth theories
     Full Idea: Kripke established that, contrary to the prevalent Tarskian dogma, attributions of truth do not always force a move to a metalanguage.
     From: report of Saul A. Kripke (Outline of a Theory of Truth [1975], 5.1) by Anil Gupta - Truth
     A reaction: [Gupta also cites Martin and Woodruff 1975]
1976 A Problem about Substitutional Quantification?
p.165 The substitutional quantifier is not in competition with the standard interpretation
     Full Idea: Kripke proposes that the substitutional quantifier is not a replacement for, or in competition with, the standard interpretation.
     From: report of Saul A. Kripke (A Problem about Substitutional Quantification? [1976]) by Ruth Barcan Marcus - Nominalism and Substitutional Quantifiers p.165
1979 A Puzzle about Belief
p.221 Puzzled Pierre has two mental files about the same object
     Full Idea: In Kripke's puzzle about belief, the subject has two distinct mental files about one and the same object.
     From: comment on Saul A. Kripke (A Puzzle about Belief [1979]) by François Recanati - Mental Files 17.1
     A reaction: [Pierre distinguishes 'London' from 'Londres'] The Kripkean puzzle is presented as very deep, but I have always felt there was a simple explanation, and I suspect that this is it (though I will leave the reader to think it through, as I'm very busy…).
1980 Naming and Necessity preface
p.03 p.3 The indiscernibility of identicals is as self-evident as the law of contradiction
     Full Idea: It seems to me that the Leibnizian principle of the indiscernibility of identicals (not to be confused with the identity of indiscernibles) is as self-evident as the law of contradiction.
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.03)
     A reaction: This seems obviously correct, as it says no more than that a thing has whatever properties it has. If a difference is discerned, either you have made a mistake, or it isn't identical.
p.03 p.3 With the necessity of self-identity plus Leibniz's Law, identity has to be an 'internal' relation
     Full Idea: It is clear from (x)□(x=x) and Leibniz's Law that identity is an 'internal' relation: (x)(y)(x=y ⊃ □x=y). What pairs (w,y) could be counterexamples? Not pairs of distinct objects, …nor an object and itself.
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.03)
     A reaction: I take 'internal' to mean that the necessity of identity is intrinsic to the item(s), and not imposed by some other force.
p.08 n9 p.8 A man has two names if the historical chains are different - even if they are the same!
     Full Idea: Two totally distinct 'historical chains' that be sheer accident assign the same name to the same man should probably count as creating distinct names despite the identity of the referents.
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.08 n9)
     A reaction: A nice puzzle for his own theory. 'What's you name?' 'Alice, and Alice!'
p.14 p.14 The very act of designating of an object with properties gives knowledge of a contingent truth
     Full Idea: If a speaker introduced a designator into a language by a ceremony, then in virtue of his very linguistic act, he would be in a position to say 'I know that Fa', but nevertheless 'Fa' would be a contingent truth (provided F is not an essential property).
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.14)
     A reaction: If someone else does the designation, I seem to have contingent knowledge that the ceremony has taken place. You needn't experience the object, but you must experience the ceremony, even if you perform it.
p.15 p.15 Instead of talking about possible worlds, we can always say "It is possible that.."
     Full Idea: We should remind ourselves the 'possible worlds' terminology can always be replaced by modal talk, such as "It is possible that…"
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.15)
     A reaction: Coming from an originator of the possible worlds idea, this is a useful reminder that we don't have to get too excited about the ontological commitments involved. It may be just a 'way to talk', and hence a tool, rather than a truth about reality.
p.16 p.16 Probability with dice uses possible worlds, abstractions which fictionally simplify things
     Full Idea: In studying probabilities with dice, we are introduced at a tender age to a set of 36 (miniature) possible worlds, if we (fictively) ignore everything except the two dice. …The possibilities are abstract states of the dice, not physical entities.
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.16)
     A reaction: Interesting for the introduction by the great man of the words 'fictional' and 'abstract' into the discussion. He says elsewhere that he takes worlds to be less than real, but more than mere technical devices.
p.19 n18 p.19 I don't think possible worlds reductively reveal the natures of modal operators etc.
     Full Idea: I do not think of 'possible worlds' as providing a reductive analysis in any philosophically significant sense, that is, as uncovering the ultimate nature, from either an epistemological or a metaphysical view, of modal operators, propositions etc.
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.19 n18)
     A reaction: I think this remark opens the door for Kit Fine's approach, of showing what modality is by specifying its sources. Possible worlds model the behaviour of modal inferences.
p.19 n18 p.19 Possible worlds allowed the application of set-theoretic models to modal logic
     Full Idea: The main and the original motivation for the 'possible worlds analysis' - and the way it clarified modal logic - was that it enabled modal logic to be treated by the same set theoretic techniques of model theory used successfully in extensional logic.
     From: Saul A. Kripke (Naming and Necessity preface [1980], p.19 n18)
     A reaction: So they should be ascribed the same value that we attribute to classical model theory, whatever that is.
1982 Wittgenstein on Rules and Private Language
p.-6 Kripke's Wittgenstein says meaning 'vanishes into thin air'
     Full Idea: Quine and Kripke's Wittgenstein attempt to argue that there are no facts about meaning, that the notion of meaning, as Kripke puts it, 'vanishes into thin air'.
     From: report of Saul A. Kripke (Wittgenstein on Rules and Private Language [1982]) by Alexander Miller - Philosophy of Language Pref
     A reaction: A tempting solution to the problem. If, though, it is possible for someone to say something that is self-evidently meaningless, or to accuse someone of speaking (deep down) without meaning, then that needs explaining.
p.160 The sceptical rule-following paradox is the basis of the private language argument
     Full Idea: Kripke argues that the 'rule-following paradox' is essential to the more controversial private language argument, and introduces a radically new form of scepticism.
     From: report of Saul A. Kripke (Wittgenstein on Rules and Private Language [1982]) by Robert Hanna - Rationality and Logic 6.1
     A reaction: It certainly seems that Kripke is right to emphasise the separateness of the two, as the paradox is quite persuasive, but the private language argument seems less so.
p.163 Community implies assertability-conditions rather than truth-conditions semantics
     Full Idea: If we take account of the fact that a speaker is in a community, then we must adopt an assertability-conditions semantics (based on what is legitimately assertible), and reject truth-conditional semantics (based on correspondence to the facts).
     From: report of Saul A. Kripke (Wittgenstein on Rules and Private Language [1982]) by Robert Hanna - Rationality and Logic 6.1
     A reaction: [Part of Hanna's full summary of Kripke's argument] This sounds wrong to me. There are conditions where it is agreed that a lie should be told. Two people can be guilty of the same malapropism.
2 p.9 'Quus' means the same as 'plus' if the ingredients are less than 57; otherwise it just produces 5
     Full Idea: I will define 'quus' by x-quus-y = x + y, if x, y < 57, and otherwise it equals 5. Who is to say that this is not the function I previously meant by '+'?
     From: Saul A. Kripke (Wittgenstein on Rules and Private Language [1982], 2)
     A reaction: Kripke's famous example, to illustrate the big new scepticism introduced by Wittgenstein's questions about the rationality of following a rule. I suspect that you have to delve into psychology to understand rule-following, rather than logic.
2 p.22 If you ask what is in your mind for following the addition rule, meaning just seems to vanish
     Full Idea: What can there be in my mind that I make use of when I follow a general rule to add in the future? It seems that the entire idea of meaning vanishes into thin air.
     From: Saul A. Kripke (Wittgenstein on Rules and Private Language [1982], 2)
     A reaction: Introspection probably isn't the best way to investigate the phenomenon of meaning. Indeed it seems rather old-fashioned and Cartesian. Kripke says, though, that seeking 'tacit' rules is even worse [end of note 22].
3 p.82 No rule can be fully explained
     Full Idea: Every explanation of a rule could conceivably be misunderstood.
     From: Saul A. Kripke (Wittgenstein on Rules and Private Language [1982], 3)
     A reaction: This is Kripke's summary of what he takes to be Wittgenstein's scepticism about rules.