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10. Modality / C. Sources of Modality / 1. Sources of Necessity

[general views on what gives rise to necessity]

28 ideas
Divine nature makes all existence and operations necessary, and nothing is contingent [Spinoza]
     Full Idea: All things are conditioned by the necessity of the divine nature, not only to exist, but also to exist and operate in a particular manner, and there is nothing that is contingent.
     From: Baruch de Spinoza (The Ethics [1675], I Pr 29)
     A reaction: This obviously invites the response of the empiricist: how does he know that? Hume says he can't know it, and Leibniz says he knows it a priori. Traditionally, 'necessary' is the dubious term, but maybe it is 'contingent' which is meaningless.
Necessity cannot be extracted from an empirical proposition [Kant]
     Full Idea: It is a clear contradiction to try to extract necessity from an empirical proposition.
     From: Immanuel Kant (Critique of Practical Reason [1788], Pref)
     A reaction: This is precisely the idea which Kripke challenged, claiming that the necessary essences of natural kinds such as gold have to be discovered empirically. All my intuitions are with Kant (and Hume) on this, but it is a complex issue…
All necessity arises from causation, which is conditioned; there is no absolute or unconditioned necessity [Schopenhauer]
     Full Idea: Necessity has no meaning other than the irresistible sequence of the effect where the cause is given. All necessity is thus conditioned, and absolute or unconditioned necessity is a contradiction in terms.
     From: Arthur Schopenhauer (Abstract of 'The Fourfold Root' [1813], Ch.VIII)
     A reaction: I.e. there is only natural necessity, and no such thing as metaphysical necessity. But what about logical necessity(e.g. 2+3=5)? I think there may be metaphysical necessity, but we can't know much about it, and we are over-confident in assessing it.
The truth-maker for a truth must necessitate that truth [Armstrong]
     Full Idea: The truth-maker for a truth must necessitate that truth.
     From: David M. Armstrong (A World of States of Affairs [1997], p.115), quoted by Pascal Engel - Truth Ch.1
     A reaction: Armstrong's 'truth-make principle'. It seems to be a necessity which is neither natural nor analytic, making it metaphysically necessary. Or is it part of the definition of truth?
Metaphysical necessities are those depending on the essential nature of things [Ellis]
     Full Idea: A metaphysically necessary proposition is one that is true in virtue of the essential nature of things.
     From: Brian Ellis (The Metaphysics of Scientific Realism [2009], 6)
     A reaction: It take this to be what Kit Fine argues for, though it tracks back to Aristotle. I also take it to be correct, though one might ask whether there are any other metaphysical necessities, ones not depending on essences.
I don't think possible worlds reductively reveal the natures of modal operators etc. [Kripke]
     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.
De re necessity arises from the way the world is [Newton-Smith]
     Full Idea: A necessary truth is 'de re' if its necessity arises from the way the world is.
     From: W.H. Newton-Smith (The Rationality of Science [1981], VII.6)
If we are told the source of necessity, this seems to be a regress if the source is not already necessary [Blackburn]
     Full Idea: If we ask why A must be the case, and A is then proved from B, that explains it if B must be so. If the eventual source cites some truth F, then if F just is so, there is strong pressure to feel that the original necessity has not been explained.
     From: Simon Blackburn (Morals and Modals [1987], 1)
     A reaction: [compressed] Ross Cameron wrote a reply to this which I like. I'm fishing for the idea that essence is the source of necessity (as Kit Fine says), but that essence itself is not necessary (as only I say, apparently!).
If something underlies a necessity, is that underlying thing necessary or contingent? [Blackburn, by Hale/Hoffmann,A]
     Full Idea: Blackburn asks of what theorists propose as underlying the necessity of a proposition, the question whether they themselves are conceived as obtaining of necessity or merely contingently.
     From: report of Simon Blackburn (Morals and Modals [1987], p.120-1) by Bob Hale/ Aviv Hoffmann - Introduction to 'Modality' 1
     A reaction: I've seen a reply to this somewhere: I think the thought was that a necessity wouldn't be any less necessary if it had a contingent source, any more than the father of a world champion boxer has to be a world champion boxer.
Objectual modal realists believe in possible worlds; non-objectual ones rest it on the actual world [McFetridge]
     Full Idea: The 'objectual modal realist' holds that what makes modal beliefs true are certain modal objects, typically 'possible worlds'. ..The 'non-objectual modal realist' says modal judgements are made true by how things stand with respect to this world.
     From: Ian McFetridge (Logical Necessity: Some Issues [1986], §2)
     A reaction: I am an enthusiastic 'non-objectual modal realist'. I accept the argument that real possible worlds have no relevance to the actual world, and explain nothing (see Jubien). The possibilities reside in the 'powers' of this world. See Molnar on powers.
To analyse modality, we must give accounts of objects, properties and relations [Jubien]
     Full Idea: The ultimate analysis of possibility and necessity depends on two important ontological decisions: the choice of an analysis of the intuitive concept of a physical object, and the other is the positing of properties and relations.
     From: Michael Jubien (Possibility [2009], Intro)
     A reaction: In the same passage he adopts Quine's view of objects, leading to mereological essentialism, and a Platonic view of properties, based on Lewis's argument for taking some things at face value. One might start with processes and events instead.
Modality concerns relations among platonic properties [Jubien]
     Full Idea: I think modality has to do with relations involving the abstract part of the world, specifically with relations among (Platonic) properties.
     From: Michael Jubien (Possibility [2009], 3.2)
     A reaction: [Sider calls Jubien's the 'governance' view, since abstract relations govern the concrete] I take Jubien here (having done a beautiful demolition job on the possible worlds account of modality) to go spectacularly wrong. Modality starts in the concrete.
The subject of a proposition need not be the source of its necessity [Fine,K]
     Full Idea: We naturally suppose, if a subject-predicate proposition is necessary, that the subject of the proposition is the source of the necessity. But that singleton 2 contains 2 is necessary, whether the number or the set is the subject of the proposition.
     From: Kit Fine (Essence and Modality [1994], p. 9)
     A reaction: A very nice addition to his general attack on the idea that essence should be accounted for in terms of his necessity. He asks a beautifully simple question: for each necessity that we accept, what is the source of that necessity?
Each basic modality has its 'own' explanatory relation [Fine,K]
     Full Idea: I am inclined to the view that ....each basic modality should be associated with its 'own' explanatory relation.
     From: Kit Fine (Guide to Ground [2012], 1.01)
     A reaction: He suggests that 'grounding' connects the various explanatory relations of the different modalities. I like this a lot. Why assert any necessity without some concept of where the necessity arises, and hence where it is grounded? You've got to eat.
Every necessary truth is grounded in the nature of something [Fine,K]
     Full Idea: It might be held as a general thesis that every necessary truth is grounded in the nature of certain items.
     From: Kit Fine (Guide to Ground [2012], 1.11)
     A reaction: [He cites his own 1994 for this] I'm not sure if I can embrace the 'every' in this. I would only say, more cautiously, that I can only make sense of necessity claims when I see their groundings - and I don't take a priori intuition as decent grounding.
The role of semantic necessity in semantics is like metaphysical necessity in metaphysics [Fine,K, by Hale/Hoffmann,A]
     Full Idea: Fine's paper argues that the notion of semantic necessity has a role to play in understanding the nature and content of semantics comparable to the role of metaphysical necessity in metaphysics.
     From: report of Kit Fine (Semantic Necessity [2010]) by Bob Hale/ Aviv Hoffmann - Introduction to 'Modality' 2
Each area of enquiry, and its source, has its own distinctive type of necessity [Fine,K]
     Full Idea: The three sources of necessity - the identity of things, the natural order, and the normative order - have their own peculiar forms of necessity. The three main areas of human enquiry - metaphysics, science and ethics - each has its own necessity.
     From: Kit Fine (The Varieties of Necessity [2002], 6)
     A reaction: I would treat necessity in ethics with caution, if it is not reducible to natural or metaphysical necessity. Fine's proposal is interesting, but I did not find it convincing, especially in its view that metaphysical necessity doesn't intrude into nature.
Rather than define counterfactuals using necessity, maybe necessity is a special case of counterfactuals [Williamson, by Hale/Hoffmann,A]
     Full Idea: Instead of regarding counterfactuals as conditionals restricted to a range of possible worlds, we can define the necessity operator by means of counterfactuals. Metaphysical necessity is a special case of ordinary counterfactual thinking.
     From: report of Timothy Williamson (Modal Logic within Counterfactual Logic [2010]) by Bob Hale/ Aviv Hoffmann - Introduction to 'Modality' 2
     A reaction: [compressed] I very much like Williamson's approach, of basing these things on the ordinary way that ordinary people think. To me it is a welcome inclusion of psychology into metaphysics, which has been out in the cold since Frege.
It seems that we cannot show that modal facts depend on non-modal facts [Hale]
     Full Idea: I think we may conclude that there is no significant version of modal supervenience which both commands acceptance and implies that all modal facts depend asymmetrically on non-modal ones.
     From: Bob Hale (Necessary Beings [2013], 03.4.3)
     A reaction: This is the conclusion of a sustained and careful discussion, recorded here for interest. I'm inclined to think that there are very few, if any, non-modal facts in the world, if those facts are accurately characterised.
Explanation of necessity must rest on something necessary or something contingent [Hale]
     Full Idea: The dilemma is that to give the ultimate source of any necessity, we must either appeal to something which could not have been otherwise (i.e. is itself necessary), or advert to something which could have been otherwise (i.e. is itself merely contingent).
     From: Bob Hale (The Source of Necessity [2002], p.301)
     A reaction: [Hale is summarising Blackburn's view, and going on to disagree with it] Hale looks for a third way, but Blackburn seems to face us with quite a plausible dilemma.
Why is this necessary, and what is necessity in general; why is this necessary truth true, and why necessary? [Hale]
     Full Idea: We must distinguish between explaining particular necessities and explaining necessity in general; and we ought to distinguish between explaining, in regard to any necessary truth, why it is true, and explaining why it is necessary.
     From: Bob Hale (The Source of Necessity [2002], p.308)
     A reaction: Useful. The pluralist view I associate with Fine says we can explain types of necessity, but not necessity in general. If we seek truthmakers, there is a special case of what adds the necessity to the truth.
The explanation of a necessity can be by a truth (which may only happen to be a necessary truth) [Hale]
     Full Idea: My claim is that there are non-transitive explanations of necessities, where what explains is indeed necessary, but what explains the necessity of the explanandum is not the explanation's necessity, but its truth simpliciter.
     From: Bob Hale (The Source of Necessity [2002], p.311)
     A reaction: The big idea is to avoid a regress of necessities. The actual truths he proposes are essentialist. An interesting proposal. It might depend on how one views essences (as giving identity, or causal power)
Humeans say that we decide what is necessary [Sider]
     Full Idea: The spirit of Humeanism is that necessity is not a realm to be discovered. We draw the lines around what is necessary.
     From: Theodore Sider (Writing the Book of the World [2011], 12.3)
     A reaction: I disagree, but it is hard to argue the point. My intuitions are that the obvious necessities of logic and mathematics reflect the way nature has to be. The deepest necessities are patterns (about which God has no choice).
Modal terms in English are entirely contextual, with no modality outside the language [Sider]
     Full Idea: English modals are context-dependent through and through; there is no stable 'outer modality'.
     From: Theodore Sider (Writing the Book of the World [2011], 12.7)
     A reaction: Sider has been doing so well up to here. To me this is swallowing the bait of linguistic approaches to philosophy which he has fought so hard to avoid.
Are necessary truths rooted in essences, or also in basic grounding laws? [Rosen]
     Full Idea: Fine says a truth is necessary when it is a logical consequence of the essential truths, but maybe it is a consequence of the essential truths together with the basic grounding laws (the 'Moorean connections').
     From: Gideon Rosen (Metaphysical Dependence [2010], 13)
     A reaction: I'm with Fine all the way here, as we really don't need to clog nature up with things called 'grounding laws', which are both obscure and inexplicable. Fine's story is the one for naturalistically inclined philosophers.
Blackburn fails to show that the necessary cannot be grounded in the contingent [Cameron]
     Full Idea: I conclude that Blackburn has not shown that any grounding of the necessary in the contingent (the Contingency Horn of his dilemma) is doomed to failure.
     From: Ross P. Cameron (On the Source of Necessity [2010], 2)
     A reaction: [You must read the article for details of Cameron's argument!] He goes on to also reject the Necessity Horn (that there is a regress if necessities must rely on necessities).
Possible worlds are just not suitable truthmakers for modality [Jacobs]
     Full Idea: Possible worlds are just not the sorts of things that could ground modality; they are not suitable truthmakers.
     From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], §3)
     A reaction: Are possible world theorists actually claiming that the worlds 'ground' modality? Maybe Lewis is, since all those concrete worlds had better do some hard work, but for the ersatzist they just provide a kind of formal semantics, leaving ontology to others.
Maybe truths are necessitated by the facts which are their truthmakers [Mumford/Anjum]
     Full Idea: Some truthmaker theorists are truthmaker necessitarians, believing that the way facts in the world make certain propositions true is by necessitating them.
     From: S.Mumford/R.Lill Anjum (Getting Causes from Powers [2011], 3.10)
     A reaction: [The cite Armstrong 2007:5-6] I don't believe in this sort of proposition (which turns out, on close inspection, to be just another way of referring to 'the facts'). Propositions are our attempts to express facts, so they can't be necessitated.