Ideas from 'A Powers Theory of Modality' by Jonathan D. Jacobs [2010], by Theme Structure

[found in 'Philosophical Studies' (ed/tr -) [- ,]].

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3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
Unlike correspondence, truthmaking can be one truth to many truthmakers, or vice versa
                        Full Idea: I assume a form of truthmaking theory, ..which is a many-many relation, unlike, say correspondence, so that one entity can make multiple truths true and one truth can have multiple truthmakers.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 1)
                        A reaction: This sounds like common sense, once you think about it. One tree makes many things true, and one statement about trees is made true by many trees.
8. Modes of Existence / A. Relations / 3. Structural Relations
If structures result from intrinsic natures of properties, the 'relations' between them can drop out
                        Full Idea: If a relation holds between two properties as a result of their intrinsic natures, then it appears the relation between the properties is not needed to do the structuring of reality; the properties themselves suffice to fix the structure.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.1)
                        A reaction: [the first bit quotes Jubien 2007] He cites a group of scientific essentialists as spokesmen for this view. Sounds right to me. No on seems able to pin down what a relation is - which may be because there is no such entity.
8. Modes of Existence / C. Powers and Dispositions / 1. Powers
Science aims at identifying the structure and nature of the powers that exist
                        Full Idea: Scientific practice seems aimed precisely at identifying the structure and nature of the powers that exist.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.3)
                        A reaction: Good. Friends of powers should look at this nice paper by Jacobs. There is a good degree of support for this view from pronouncements of modern scientists. If scientists don't support it, they should. Otherwise they are trapped in the superficial.
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
Powers come from concrete particulars, not from the laws of nature
                        Full Idea: The source of powers is not the laws of nature; it is the powerful nature of the ordinary properties of concrete particulars.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.2)
                        A reaction: This pithily summarises my own view. People who think the powers of the world derive from the laws either have an implicit religious framework, or they are giving no thought at all to the ontological status of the laws.
10. Modality / A. Necessity / 10. Impossibility
Possibilities are manifestations of some power, and impossibilies rest on no powers
                        Full Idea: To be possible is just to be one of the many manifestations of some power, and to be impossible is to be a manifestation of no power.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.2.1)
                        A reaction: [This remark occurs in a discussion of theistic Aristotelianism] I like this. If we say that something is possible, the correct question is to ask what power could bring it about.
10. Modality / B. Possibility / 1. Possibility
States of affairs are only possible if some substance could initiate a causal chain to get there
                        Full Idea: A non-actual state of affairs in possible if there actually was a substance capable of initiating a causal chain, perhaps non-deterministic, that could lead to the state of affairs that we claim is possible.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.2)
                        A reaction: [He is quoting A.R. Pruss 2002] That seems exactly right. Of course the initial substance(s) might create a further substance, such as a transuranic element, which then produces the state of affairs. I favour this strongly actualist view.
10. Modality / B. Possibility / 9. Counterfactuals
Counterfactuals invite us to consider the powers picked out by the antecedent
                        Full Idea: A counterfactual is an invitation to consider what the properties picked out by the antecedent are powers for (where Lewis 1973 took it to be an invitation to consider what goes on in a selected possible world).
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.4.3)
                        A reaction: A beautifully simple proposal from Jacobs, with which I agree. This seems to be an expansion of the Ramsey test for conditionals, where you consider the antecedent being true, and see what follows. What, we ask Ramsey, would make it follow?
10. Modality / C. Sources of Modality / 1. Sources of Necessity
Possible worlds are just not suitable truthmakers for modality
                        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.
10. Modality / C. Sources of Modality / 5. Modality from Actuality
All modality is in the properties and relations of the actual world
                        Full Idea: Properties and the relations between them introduce modal connections in the actual world. ..This is a strong form of actualism, since all of modality is part of the fundamental fabric of the actual world.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4)
                        A reaction: This is the view of modality which I find most congenial, with the notion of 'powers' giving us the conceptual framework on which to build an account.
10. Modality / C. Sources of Modality / 6. Necessity from Essence
We can base counterfactuals on powers, not possible worlds, and hence define necessity
                        Full Idea: Together with a definition of possibility and necessity in terms of counterfactuals, the powers semantics of counterfactuals generates a semantics for modality that appeals to causal powers and not possible worlds.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 1)
                        A reaction: Wonderful. Just what the doctor ordered. The only caveat is that if we say that reality is built up from fundamental powers, then might those powers change their character without losing their identity (e.g. gravity getting weaker)?
10. Modality / E. Possible worlds / 1. Possible Worlds / c. Possible worlds realism
Concrete worlds, unlike fictions, at least offer evidence of how the actual world could be
                        Full Idea: Lewis's concrete worlds give a better account of modality (than fictional worlds). When I learn that a man like me drives a truck, I gain evidence for the fact that I can drive a truck.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 3)
                        A reaction: Cf. Idea 12464. Jacobs still rightly rejects this as an account of possibility, since the possibility that I might drive a truck must be rooted in me, not in some other person who drives a truck, even if that person is very like me.
10. Modality / E. Possible worlds / 1. Possible Worlds / e. Against possible worlds
If some book described a possibe life for you, that isn't what makes such a life possible
                        Full Idea: Suppose somewhere deep in the rain forest is a book that includes a story about you as a truck-driver. I doubt that you would be inclined the think that that story, that book, is the reason you could have been a truck driver.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 3)
                        A reaction: This begins to look like a totally overwhelming and obvious reason why possible worlds (especially as stories) don't give a good metaphysical account of possibility. They provide a semantic structure for modal reasoning, but that is entirely different.
Possible worlds semantics gives little insight into modality
                        Full Idea: If we want our semantics for modality to give us insight into the truthmakers for modality, then possible worlds semantics is inadequate.
                        From: Jonathan D. Jacobs (A Powers Theory of Modality [2010], 4.4)
                        A reaction: [See the other ideas of Jacobs (and Jubien) for this] It is an interesting question whether a semantics for a logic is meant to give us insight into how things really are, or whether it just builds nice models. Satisfaction, or truth?