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All the ideas for 'Analyzing Modality', 'Absolute Necessities' and 'Defeasibility Theory'

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29 ideas

5. Theory of Logic / G. Quantification / 3. Objectual Quantification
'All horses' either picks out the horses, or the things which are horses [Jubien]
     Full Idea: Two ways to see 'all horses are animals' are as picking out all the horses (so that it is a 'horse-quantifier'), ..or as ranging over lots of things in addition to horses, with 'horses' then restricting the things to those that satisfy 'is a horse'.
     From: Michael Jubien (Analyzing Modality [2007], 2)
     A reaction: Jubien says this gives you two different metaphysical views, of a world of horses etc., or a world of things which 'are horses'. I vote for the first one, as the second seems to invoke an implausible categorical property ('being a horse'). Cf Idea 11116.
9. Objects / A. Existence of Objects / 1. Physical Objects
Being a physical object is our most fundamental category [Jubien]
     Full Idea: Being a physical object (as opposed to being a horse or a statue) really is our most fundamental category for dealing with the external world.
     From: Michael Jubien (Analyzing Modality [2007], 2)
     A reaction: This raises the interesting question of why any categories should be considered to be more 'fundamental' than others. I can only think that we perceive something to be an object fractionally before we (usually) manage to identify it.
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
Haecceities implausibly have no qualities [Jubien]
     Full Idea: Properties of 'being such and such specific entity' are often called 'haecceities', but this term carries the connotation of non-qualitativeness which I don't favour.
     From: Michael Jubien (Analyzing Modality [2007], 2)
     A reaction: The way he defines it makes it sound as if it was a category, but I take it to be more like a bare individual essence. If it has not qualities then it has no causal powers, so there could be no evidence for its existence.
10. Modality / A. Necessity / 2. Nature of Necessity
Absolute necessity might be achievable either logically or metaphysically [Hale]
     Full Idea: Maybe peaceful co-existence between absolute logical necessity and absolute metaphysical necessity can be secured, ..and absolute necessity is their union. ...However, a truth would then qualify as absolutely necessary in two quite different ways.
     From: Bob Hale (Absolute Necessities [1996], 4)
     A reaction: Hale is addressing a really big question for metaphysic (absolute necessity) which others avoid. In the end he votes for rejecting 'metaphysical' necessity. I am tempted to vote for rejecting logical necessity (as being relative). 'Absolute' is an ideal.
10. Modality / A. Necessity / 3. Types of Necessity
Maybe not-p is logically possible, but p is metaphysically necessary, so the latter is not absolute [Hale]
     Full Idea: It might be metaphysically necessary that p but logically possible that not-p, so that metaphysical necessity is not, after all, absolute.
     From: Bob Hale (Absolute Necessities [1996]), quoted by E.J. Lowe - The Possibility of Metaphysics 1.5
     A reaction: Lowe presents this as dilemma, but it sounds fine to me. Flying pigs etc. have no apparent logical problems, but I can't conceive of a possible world where pigs like ours fly in a world like ours. Earthbound pigs may be metaphysically necessary.
A strong necessity entails a weaker one, but not conversely; possibilities go the other way [Hale]
     Full Idea: One type of necessity may be said to be 'stronger' than another when the first always entails the second, but not conversely. This will obtain only if the possibility of the first is weaker than the possibility of the second.
     From: Bob Hale (Absolute Necessities [1996], 1)
     A reaction: Thus we would normally say that if something is logically necessary (a very strong claim) then it will have to be naturally necessary. If something is naturally possible, then clearly it will have to be logically possible. Sounds OK.
'Relative' necessity is just a logical consequence of some statements ('strong' if they are all true) [Hale]
     Full Idea: Necessity is 'relative' if a claim of φ-necessary that p just claims that it is a logical consequence of some statements Φ that p. We have a 'strong' version if we add that the statements in Φ are all true, and a 'weak' version if not.
     From: Bob Hale (Absolute Necessities [1996], 1)
     A reaction: I'm not sure about 'logical' consequence here. It may be necessary that a thing be a certain way in order to qualify for some category (which would be 'relative'), but that seems like 'sortal' necessity rather than logical.
10. Modality / A. Necessity / 5. Metaphysical Necessity
Metaphysical necessity says there is no possibility of falsehood [Hale]
     Full Idea: Friends of metaphysical necessity would want to hold that when it is metaphysically necessary that p, there is no good sense of 'possible' (except, perhaps, an epistemic one) in which it is possible that not-p.
     From: Bob Hale (Absolute Necessities [1996], 2)
     A reaction: We might want to say which possible worlds this refers to (and presumably it won't just be in the actual world). The normal claim would refer to all possible worlds. Adding a '...provided that' clause moves it from absolute to relative necessity.
10. Modality / A. Necessity / 6. Logical Necessity
'Broadly' logical necessities are derived (in a structure) entirely from the concepts [Hale]
     Full Idea: 'Broadly' logical necessities are propositions whose truth derives entirely from the concepts involved in them (together, of course, with relevant structure).
     From: Bob Hale (Absolute Necessities [1996], 3)
     A reaction: Is the 'logical' part of this necessity bestowed by the concepts, or by the 'structure' (which I take to be a logical structure)?
Logical necessities are true in virtue of the nature of all logical concepts [Hale]
     Full Idea: The logical necessities can be taken to be the propositions which are true in virtue of the nature of all logical concepts.
     From: Bob Hale (Absolute Necessities [1996], p.10)
     A reaction: This is part of his story of essences giving rise to necessities. His proposal sounds narrow, but logical concepts may have the highest degree of generality which it is possible to have. It must be how the concepts connect that causes the necessities.
10. Modality / A. Necessity / 11. Denial of Necessity
De re necessity is just de dicto necessity about object-essences [Jubien]
     Full Idea: I suggest that the de re is to be analyzed in terms of the de dicto. ...We have a case of modality de re when (and only when) the appropriate property in the de dicto formulation is an object-essence.
     From: Michael Jubien (Analyzing Modality [2007], 5)
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
Conceptual necessities are made true by all concepts [Hale]
     Full Idea: Conceptual necessities can be taken to be propositions which are true in virtue of the nature of all concepts.
     From: Bob Hale (Absolute Necessities [1996], p.9)
     A reaction: Fine endorse essences for these concepts. Could we then come up with a new concept which contradicted all the others, and destroyed the necessity? Yes, presumably. Presumably witchcraft and astrology are full of 'conceptual necessities'.
10. Modality / C. Sources of Modality / 5. Modality from Actuality
Modal propositions transcend the concrete, but not the actual [Jubien]
     Full Idea: Where modal propositions may once have seemed to transcend the actual, they now seem only to transcend the concrete.
     From: Michael Jubien (Analyzing Modality [2007], 4)
     A reaction: This is because Jubien has defended a form of platonism. Personally I take modal propositions to be perceptible in the concrete world, by recognising the processes involved, not the mere static stuff.
Your properties, not some other world, decide your possibilities [Jubien]
     Full Idea: The possibility of your having been a playwright has nothing to do with how people are on other planets, whether in our own or in some other realm. It is only to do with you and the relevant property.
     From: Michael Jubien (Analyzing Modality [2007], 1)
     A reaction: I'm inclined to think that this simple point is conclusive disproof of possible worlds as an explanation of modality (apart from Jubien's other nice points). What we need to understand are modal properties, not other worlds.
Modal truths are facts about parts of this world, not about remote maximal entities [Jubien]
     Full Idea: Typical modal truths are just facts about our world, and generally facts about very small parts of it, not facts about some infinitude of complex, maximal entities.
     From: Michael Jubien (Analyzing Modality [2007], 1)
     A reaction: I think we should embrace this simple fact immediately, and drop all this nonsense about possible worlds, even if they are useful for the semantics of modal logic.
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
We have no idea how many 'possible worlds' there might be [Jubien]
     Full Idea: As soon as we start talking about 'possible world', we beg the question of their relevance to our prior notion of possibility. For all we know, there are just two such realms, or twenty-seven, or uncountably many, or even set-many.
     From: Michael Jubien (Analyzing Modality [2007], 1)
If there are no other possible worlds, do we then exist necessarily? [Jubien]
     Full Idea: Suppose there happen to be no other concrete realms. Would we happily accept the consequence that we exist necessarily?
     From: Michael Jubien (Analyzing Modality [2007], 1)
If all possible worlds just happened to include stars, their existence would be necessary [Jubien]
     Full Idea: If all of the possible worlds happened to include stars, how plausible is it to think that if this is how things really are, then we've just been wrong to regard the existence of stars as contingent?
     From: Michael Jubien (Analyzing Modality [2007], 1)
Possible worlds just give parallel contingencies, with no explanation at all of necessity [Jubien]
     Full Idea: In the world theory, what passes for 'necessity' is just a bunch of parallel 'contingencies'. The theory provides no basis for understanding why these contingencies repeat unremittingly across the board (while others do not).
     From: Michael Jubien (Analyzing Modality [2007], 1)
If other worlds exist, then they are scattered parts of the actual world [Jubien]
     Full Idea: Any other realms that happened to exist would just be scattered parts of the actual world, not entire worlds at all. It would just happen that physical reality was fragmented in this remarkable but modally inconsequential way.
     From: Michael Jubien (Analyzing Modality [2007], 1)
     A reaction: This is aimed explicitly at Lewis's modal realism, and strikes me as correct. Jubien's key point here is that they are irrelevant to modality, just as foreign countries are irrelevant to the modality of this one.
Worlds don't explain necessity; we use necessity to decide on possible worlds [Jubien]
     Full Idea: The suspicion is that the necessity doesn't arise from how worlds are, but rather that the worlds are taken to be as they are in order to capture the intuitive necessity.
     From: Michael Jubien (Analyzing Modality [2007], 1)
     A reaction: It has always seemed to me rather glaring that you need a prior notion of 'possible' before you can start to talk about 'possible worlds', but I have always been too timid to disagree with the combination of Saul Kripke and David Lewis. Thank you, Jubien!
10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts
We mustn't confuse a similar person with the same person [Jubien]
     Full Idea: If someone similar to Humphrey won the election, that nicely establishes the possibility of someone's winning who is similar to Humphrey. But we mustn't confuse this possibility with the intuitively different possibility of Humphrey himself winning.
     From: Michael Jubien (Analyzing Modality [2007], 1)
11. Knowledge Aims / B. Certain Knowledge / 3. Fallibilism
Indefeasibility does not imply infallibility [Grundmann]
     Full Idea: Infallibility does not follow from indefeasibility.
     From: Thomas Grundmann (Defeasibility Theory [2011], 'Significance')
     A reaction: If very little evidence exists then this could clearly be the case. It is especially true of historical and archaeological evidence.
13. Knowledge Criteria / A. Justification Problems / 1. Justification / c. Defeasibility
Can a defeater itself be defeated? [Grundmann]
     Full Idea: Can the original justification of a belief be regained through a successful defeat of a defeater?
     From: Thomas Grundmann (Defeasibility Theory [2011], 'Defeater-Defs')
     A reaction: [Jäger 2005 addresses this] I would have thought the answer is yes. I aspire to coherent justifications, so I don't see justifications as a chain of defeat and counter-defeat, but as collective groups of support and challenge.
Simple reliabilism can't cope with defeaters of reliably produced beliefs [Grundmann]
     Full Idea: An unmodified reliabilism does not accommodate defeaters, and surely there can be defeaters against reliably produced beliefs?
     From: Thomas Grundmann (Defeasibility Theory [2011], 'Defeaters')
     A reaction: [He cites Bonjour 1980] Reliabilism has plenty of problems anyway, since a generally reliable process can obviously occasionally produce a bad result. 20:20 vision is not perfect vision. Internalist seem to like defeaters.
You can 'rebut' previous beliefs, 'undercut' the power of evidence, or 'reason-defeat' the truth [Grundmann]
     Full Idea: There are 'rebutting' defeaters against the truth of a previously justified belief, 'undercutting' defeaters against the power of the evidence, and 'reason-defeating' defeaters against the truth of the reason for the belief.
     From: Thomas Grundmann (Defeasibility Theory [2011], 'How')
     A reaction: That is (I think) that you can defeat the background, the likelihood, or the truth. He cites Pollock 1986, and implies that these are standard distinctions about defeaters.
Defeasibility theory needs to exclude defeaters which are true but misleading [Grundmann]
     Full Idea: Advocates of the defeasibility theory have tried to exclude true pieces of information that are misleading defeaters.
     From: Thomas Grundmann (Defeasibility Theory [2011], 'What')
     A reaction: He gives as an example the genuine news of a claim that the suspect has a twin.
Knowledge requires that there are no facts which would defeat its justification [Grundmann]
     Full Idea: The 'defeasibility theory' of knowledge claims that knowledge is only present if there are no facts that - if they were known - would be genuine defeaters of the relevant justification.
     From: Thomas Grundmann (Defeasibility Theory [2011], 'What')
     A reaction: Something not right here. A genuine defeater would ensure the proposition was false, so it would simply fail the truth test. So we need a 'defeater' for a truth, which must therefore by definition be misleading. Many qualifications have to be invoked.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
'Moderate' foundationalism has basic justification which is defeasible [Grundmann]
     Full Idea: Theories that combine basic justification with the defeasibility of this justification are referred to as 'moderate' foundationalism.
     From: Thomas Grundmann (Defeasibility Theory [2011], 'Significance')
     A reaction: I could be more sympathetic to this sort of foundationalism. But it begins to sound more like Neurath's boat (see Quine) than like Descartes' metaphor of building foundations.