You’ll have to explain further the point of this thread?

It means there is a feasible potential for said person buying an ice cream. Just because an outcome is binary it doesn’t make the prediction absolute - or it wouldn’t be a ‘prediction’. Uncertainty is a necessary part of human life.

What’s the real issue here?

Is there a chance you are referring to ‘trope nominalism’?

There certainly seems to be a ‘nominalist’ leaning here?

It means there is some possible world where that happens.

The simple answer is that "Mary might buy ice cream" is true iff there is an accessible world in which Mary buys ice cream. The heart of your question is: what is meant by an accessible world? The simplest answer is: a possible world $w$ is accessible from our world iff $w$ can be imagined without contradiction. A more restrictive answer is: $w$ is accessible from our world iff $w$ can be obtained from our world through physical processes. A more metaphysically adventurous answer is: $w$ is accessible from our world iff $w$ exists. The last answer probably commits you to strong forms of modal realism. In general, I think you need to make your question more precise in order to elicit interesting discussion.

It means that we don't know whether they will or they wont buy ice cream.

Accessibility relations tend to be reflexive.

"If I punch my laptop screen, it might break" doesn't have to mean "There is another possible world in which my laptop screen is broken as a result of my punching it" surely? It could equally mean that it is something which might happen in this one.

Must this be the same kind of possibility as stipulating another possible (counterfactual, developmentally entailed, temporally precedent...)?

"If I punch my laptop screen, it might break" doesn't have to mean "There is another possible world in which my laptop screen is broken as a result of my punching it" surely? It could equally mean that it is something which might happen in this one. — fdrake

That bolded "another" is the problem here. It doesn't have to be another possible world, just some possible world. It can be this one, or another, and still be some one.

Also since that's a conditional sentence, it's not even saying that there is some possible world where you do punch your laptop screen, it's saying that in some subset of the possible worlds where you punch your laptop screen (which could be a set of zero possible worlds, if you would never do that) it breaks.

That bolded "another" is the problem here. It doesn't have to be another possible world, just some possible world. It can be this one, or another, and still be some one. — Pfhorrest

"If I punch my laptop screen, it might break"
"What does that might mean?"
"In some possible world"
"That includes this one?"
"Yes, the actual world is a possible world since it is a reflexive accessibility relation"
"Doesn't that mean if I punch my laptop screen, it will break?"
"No, it only might, because we don't know if the world where the laptop screen breaks when you punch it is this world or another world"

Yeah, that sounds accurate. I'm not sure if you're just confirming you understand the discussion so far correctly, or trying to highlight a problem with it, or something?

Just some thoughts on my frustrations with modal logic and how it relates to any metaphysics of possibility.

That the last step doesn't say anything about what it would mean for the laptop screen to break; to be capable of breaking when struck hard enough. There's a whole metaphysics of potential and actuality which is just elided by making the connection between how the actual world develops and what it may possibly become of precisely the same character.

What allows us to assign accessible worlds to each other in a network of accessibility is a nascent understanding of modality; a physics, a metaphysics, a criterion of logical consistency etc; which is modelled by stipulated properties of the accessibility relation in question. This is the elided metaphysics. A method of presenting an account of (a type of) possibility is much different from determining what an adequate account of (that type of) possibility is; or only a partial picture. A modal logic and its characterising accessibility relation is a map, the domain studied and its metaphysics of development is the territory.

EG: Causal possibilities often have order-like (antisymmetric, transitive) accessibility relations - this just says that cause always precedes effect. But we know that that has issues in some domains. How you'd find out about the issues which change the principles a modal logic works by isn't just about selecting "the right theorems", it's about assessing whether the axioms and theorems (the whole structure) fit the domain. And this is tricky, since:

"Might" has lots of valences, as does "possible", but when we speak of possibility in terms of possible worlds, we implicitly quantify possibility in the discussion over accessibility relations; each of which has a distinct picture of possibility within it. To say "possibility is just saying that the thing happens in some possible world" isn't an account of possibility of the event, what it means for that event to be possible (like what it means for a political party to be electable), it's a way of deferring the question that confuses map and territory; or modelling device and targeted domain.

Edit: another part of this limitation is that possibility and necessity in a modal logic really are statements about graph connectivity; which worlds are connected to which other worlds, whether a path exists and what facts hold in the reachable nodes; not about what it means for one world to transition into another; what it means for something to have a capacity to develop in this or that way. It could be said that what it means for an entity E to have a capacity to develop in way X is for the characteristic properties of development associated with X to be in an accessible world from E, but there's still that question of transition, the development of E in way X is as much about transition properties as connectivity properties of the accessibility graph. So yes, it might happen, but the way matters; such graphs picture state transition with arbitrary means. "How could it happen?" "I don't care because it's possible"

Agree, nodding in the direction of modal logic by rephrasing the problem statement using possible world semantics is ass-backwards when answering someone who asks about the meaning of modal talk outside the context of formal logic. We should rather start by analyzing the modal language, and from there, since language games are usually more than just an abstract exercise, we can proceed to grounding modal talk in some explanatory framework - naturalizing it, for example.

I think I disagree. The best analysis of modal language we possess is possible worlds semantics. By systematically translating modal talk into talk about possible worlds, questions about counterfactuals can be made precise. The question then becomes: which accessibility relations are germane to our universe? The metaphysics are not elided, but simply shifted to your prescriptions for possible answers. If you are satisfied with considering folk models, then the folk understanding of causality is sufficient to interpret the accessibility relation.

In other words, if you want accessible worlds to be imaginable worlds, or physically reachable worlds, or whatever, you should state that beforehand. It doesn't make sense to ask about the meaning of "might" without also specifying what you consider an acceptable answer. But specifying an acceptable answer determines a metaphysics, and therefore circumscribes the set of accessible worlds.

I think I disagree. — quickly

For the most part it looks like a difference in emphasis to me.

The question then becomes: which accessibility relations are germane to our universe? — quickly

Which is not something that can be decided by modal logic in full. You pick the axioms that capture whatever sense of modality seems relevant. Hell, you might even want to pick theorems and find axioms that produce them. "Possibly necessary => necessary => true in this world" is very attractive if you want the modal ontological argument to go through. Otherwise - "It is possibly necessary (in the sense of a covering law) that light requires the aether as a transmission medium, therefore it is necessary that light requires the aether as a medium, therefore light requires the aether as a medium", and it does not.

So maybe the accessibility relation can't be an equivalence relation for modalities concerning physical law; but for transcendent a-priori rationally considered possibilities...

It isn't just a matter of modelling, there's a matter of deciding which modalities are meaningful to model and in what context.

But specifying an acceptable answer determines a metaphysics, and therefore circumscribes the set of accessible worlds. — quickly

But this is very backwards, at least in part, if you're using a modal logic to represent metaphysical intuitions, the metaphysical intuitions, the axioms and the theorems all interact; a feeding forward of "acceptable answers" into "metaphysical accounts" makes the appropriate metaphysics for a domain rather arbitrary; or if not arbitrary, we consider the acceptable answers through metaphysical arguments, and at that point we're not just talking about the formal structure of a modal logic either. The extra logical considerations in part determine what logical structure seems appropriate to represent them, so do in part the theorems and axioms of the logic.

Edit: there's also the transition problem I highlighted. The possible world where a ball rolls down a hill instead of being stuck at the top of it is accessible from the one where the ball is at the top of it in the sense of physical possibility; but the sense of physical potential which mechanises this transition between the possible worlds (stuck now, rolling) simultaneously establishes the possibility (because it could happen in some way) but does not care how it happened at all. It emaciates any metaphysics of potential tied to the actual by suspending any consideration of how things work.

I think I disagree. The best analysis of modal language we possess is possible worlds semantics. By systematically translating modal talk into talk about possible worlds, questions about counterfactuals can be made precise. — quickly

I think this is a mistake. In order to make sense of a phenomenon - modal talk - you pick a simple formal model that captures some of its structure, and then you try to make sense of your model by studying more of its structure and trying to relate it back to phenomenology. This is what's backwards. You shouldn't lose sight of the phenomenology, and don't expect to find in your model any insight that you didn't front-load there.

On the flip side, as @fdrake points out, modal logic is too impoverished a model to capture the varieties and ambiguities of meaning and function of modal talk.

But this is very backwards, at least in part, if you're using a modal logic to represent metaphysical intuitions, the metaphysical intuitions, the axioms and the theorems all interact; a feeding forward of "acceptable answers" into "metaphysical accounts" makes the appropriate metaphysics for a domain rather arbitrary; or if not arbitrary, we consider the acceptable answers through metaphysical arguments, and at that point we're not just talking about the formal structure of a modal logic either. The extra logical considerations in part determine what logical structure seems appropriate to represent them, so do in part the theorems and axioms of the logic. — fdrake

I think this is a mistake. In order to make sense of a phenomenon - modal talk - you pick a simple formal model that captures some of its structure, and then you try to make sense of your model by studying more of its structure and trying to relate it back to phenomenology. This is what's backwards. You shouldn't lose sight of the phenomenology, and don't expect to find in your model any insight that you didn't front-load there. — SophistiCat

The position I want to defend goes something like this. Consider a counterfactual sentence like "If you had hit the baseball, the window would have broken." Before asking whether this sentence is true, you need to restrict the set of possible answers. For example, here are three possible answers that fail to satisfy most people in most circumstances: (a) the sentence is false because the universe is deterministic; (b) the sentence is true because it describes a logically consistent universe; (c) the sentence is true if modern physics is false. The reason these answers are usually unsatisfying is that most people would consider them irrelevant to determining the truth-value of the sentence in most circumstances in which the sentence arises. For example, I can't imagine any of those responses being used to settle a legal dispute between a neighborhood association and a city government building a baseball field in an adjacent park. Of course, you can always imagine situations where these responses are appropriate. My specific contention is that once the set of acceptable answers is determined, the metaphysical and logical questions are mostly settled and usually irrelevant. The "phenomenology" and "intuitions" are mostly determined by asking someone what they're looking for in an answer.

In my own field (computer science), questions about the truth of sentences often devolve into questions about the provability of sentences in various formal systems. It only makes sense to ask questions about truth and provability once you've determined which systems you're interested in. The choice of system encodes various metaphysical and logical commitments, but is usually driven by practical concerns. For example, if you're interested in provable sentences with computable witnesses, you would avoid adding non-constructive axioms to your theory. It turns out that you can't even ask what it means for a sentence to be true or false without first specifying the range of systems you're interested in.

I hope I'm not missing the point of your objections.

My specific contention is that once the set of acceptable answers is determined, the metaphysical and logical questions are mostly settled and usually irrelevant. The "phenomenology" and "intuitions" are mostly determined by asking someone what they're looking for in an answer. — quickly

I agree that once you "determine a set of acceptable answers" the "metaphysical and logical questions are mostly settled", but that process of "determining the set of acceptable answers" is precisely part of settling the metaphysical and logical questions.

The only reason, I think, that metaphysical questions concerning modality seem largely irrelevant to you (in this context) is that you (seem to) think that "determining the set of acceptable answers" has nothing to do with reasoning metaphysically about modality. Note that you expressed this using the word "acceptable"; itself a modality. Reasoning about the sense of "acceptable" there; what is appropriate for the situation is in part extra-logical; you have to think about the logic from the outside while negotiating its axiomatisation to ensure it works well for the sense of modality in question.

This isn't so much a weakness of a modal logic, it's a recognition of its limitation in scope. It's a map, there's a territory, and we negotiate which map (modal logic) to use based on the territory.

My specific contention is that once the set of acceptable answers is determined, the metaphysical and logical questions are mostly settled and usually irrelevant. The "phenomenology" and "intuitions" are mostly determined by asking someone what they're looking for in an answer. — quickly

I guess this turns on the question of what sort of an answer we are looking for: descriptive, explanatory or prescriptive. If descriptive, then reducing the subject to a formal modal logic provides a rough sketch of an answer, but it loses much of the meat in the process of reduction, and the result is only approximate at best, because in reality our modal talk/thinking does not perfectly conform to this system.

If we want an explanatory or a prescriptive answer, then the issues mentioned above really stick out. We need a good reason for concluding that a particular formal system drives our modal talk, or that it's what we ought to aspire to - other than that it's simple and convenient and something that we know how to describe.

I agree with @fdrake and @SophistiCat that I was "confusing the map with the territory." I will try to separate the core of my argument from your well-deserved critique that I was eliding metaphysical issues by reducing questions about modality to questions about formal systems.

The only reason, I think, that metaphysical questions concerning modality seem largely irrelevant to you (in this context) is that you (seem to) think that "determining the set of acceptable answers" has nothing to do with reasoning metaphysically about modality. Note that you expressed this using the word "acceptable"; itself a modality. Reasoning about the sense of "acceptable" there; what is appropriate for the situation is in part extra-logical; you have to think about the logic from the outside while negotiating its axiomatisation to ensure it works well for the sense of modality in question. — fdrake

I was using "acceptable" as a substitute for "satisfying," which I think eliminates the circularity you pointed out. In general, I think the metaphysical questions are settled (modulo pragmatically irrelevant concerns) once you've determined what you want to know about any particular sentence. In your example ("If I punch the laptop screen, it might break"), you can imagine context determining which answers are satisfying, and therefore which metaphysics are appropriate to adopt. For example, an engineer might be satisfied with a description of the screen's material properties. This might not satisfy the philosopher, but it will satisfy anyone asking whether actual punches will break actual screens.

I guess this turns on the question of what sort of an answer we are looking for: descriptive, explanatory or prescriptive. If descriptive, then reducing the subject to a formal modal logic provides a rough sketch of an answer, but it loses much of the meat in the process of reduction, and the result is only approximate at best, because in reality our modal talk/thinking does not perfectly conform to this system. — SophistiCat

The descriptive ones. If someone asks whether the laptop screen would have broken had they punched it, she would typically not be satisfied with the answer: metaphysically, all counterfactual sentences are vacuously true. This doesn't mean there aren't interesting metaphysical questions about modality (some of which have been brought up in this thread), only that questions about the meaning of modal operators in actual sentences uttered by actual speakers are uninteresting once the question "What are you looking for in an answer?" is settled.

My view seems pretty unpopular, so i will give it a name: apathetic instrumentalism.

I was using "acceptable" as a substitute for "satisfying," which I think eliminates the circularity you pointed out. — quickly

Highlighting a circularity wasn't really my intention. Noting that you used 'acceptable' there was a rhetorical move to highlight the territory knowledge required to set up a modal logic. The status of this knowledge is problematic. If it is imagined as a system of established propositions (which can be encoded as axioms) expressing the metaphysical character of the domain, we have to ask what process of reasoning, discovery and description allows the formation of that system of propositions and allows us to tailor it to the domain in question. This, precisely, is practicing metaphysics as it is relevant to the domain in question.

For example, an engineer might be satisfied with a description of the screen's material properties. This might not satisfy the philosopher, but it will satisfy anyone asking whether actual punches will break actual screens. — quickly

Maybe the engineer and the philosopher might have a common interest here. The engineering description of the compressive strength of the laptop screen engenders a series of metaphysical questions and is accompanied with its own metaphysical insights. Maybe the engineer and the philosopher would think, in an Aristotelian vein, that the compressive strength of the laptop was a potential of it - characteristic properties that engender and constrain what laptop screen will do and what it can do. The only way the screen can break is if the thrown punch can exceed the compressive strength. In context, these are "territory" considerations.

The "possible worlds" in which the laptop screen breaks develop out of the ones in which it is punched through, maybe, being subjected to a compressive force sufficiently greater than its compressive strength. Spelling out the transition mechanism of "worlds where the laptop is punched" to "worlds where the laptop breaks given a punch x": these are those worlds in which the laptop screen's compressive strength is sufficiently less than that of the punch. You then check to see if the domain of possible thrown punches (by a particular agent) is capable of applying enough force to the laptop screen to break it. Then the worlds where the laptop screen breaks given a sufficiently strong punch are connected to the worlds where that punch is thrown. These are mere "map" considerations (albeit given a rather stultifying framework for making such a map, in which we already have (weak) existential commitments to possible worlds, more than the bodies in play).

Neither the philosopher nor the engineer should be particularly happy with "it is possible that the laptop screen breaks when it is punched because it is a physical possibility", or "the laptop screen might break when struck because the possible world where the laptop screen breaks when struck is connected to the ones where the laptop is struck"...How, why does it have that status? In context? There's metaphysics elsewhere, prior to it, setting up that logic is a lot about rearranging representations when we already know how to move them about.

I'm going to have to take some time to consider your response.

You’ll have to explain further the point of this thread?

A discussion about the definition of "might", "possibly", "chance" "maybe" or "possibility". I am going to go ahead and guess that Amergin's answer is correct.

It means that we don't know whether they will or they wont buy ice cream.