Giacomo Giannini

Power theorists are divided among those who think that a dispositionalist metaphysics imbues the physical world with a dynamic and active aspect, and those who deny that. So far there has been little success in clarifying the exact nature of the two positions and their disagreement beyond trading metaphors. In this paper we suggest that one way to elucidate the idea that powers are dynamic and active is to think that a robust conception of change must play a central role in power-based explanations. We use the grounding of modality as an example. We claim that friends of dynamic powers should embrace a specific version of Dispositionalism, one in which the modal facts change over time. We then argue that this view entails an especially strong version of Necessitism and Permanentism. In turn, according to an influential view in the philosophy of time, this amounts to adopting a Moving Spotlight Theory of time. We provide some details of this power-based moving spotlight theory, its features, and potential flaws.

Power theorists are divided among those who think that a dispositionalist metaphysics imbues the physical world with a dynamic and active aspect, and those who deny that. So far there has been little success in clarifying the exact nature of the two positions and their disagreement beyond trading metaphors. In this paper we suggest that one way to elucidate the idea that powers are dynamic and active is to think that a robust conception of change must play a central role in power-based explanations. We use the grounding of modality as an example. We claim that friends of dynamic powers should embrace a specific version of Dispositionalism, one in which the modal facts change over time. We then argue that this view entails an especially strong version of Necessitism and Permanentism. In turn, according to an influential view in the philosophy of time, this amounts to adopting a Moving Spotlight Theory of time. We provide some details of this power-based moving spotlight theory, its features, and potential flaws.

In this paper I argue that even the most radical metaphysics of powers (such as that adopted by Mumford and Anjum, Cartwright, or Groff) are compatible with eternalism. I first offer a taxonomy of powers ontologies, and attempt to characterise the difference between moderate and radical powers ontologies—the latter are characterised by an emphasis on production and dynamicity. I consider an argument by C. Friebe to the effect that the productive character of powers is inconsistent with Eternalism and find it wanting. I then elucidate the notion of dynamicity that radical powers theorists employ by making apparent their link with an ontology of irreducible processes. Finally, I respond to an argument by Donatella Donati to the effect that eternalism entails a reductive account of change which is inconsistent with process ontologies, and show that the the two are compatible. I conclude that we have no reason to think that radical powers metaphysics (and, a fortiori, every powers ontology) are not compatible with eternalism.

Dispositionalism is the theory of modality that grounds all modal truths in powers: all metaphysically possible and necessary truths are to be explained by pointing to some actual power, or absence thereof. One of the main reasons to endorse dispositionalism is that it promises to deliver an especially desirable epistemology of modality. However, so far this issue has not be fully investigated with the care it is due. The aim of this paper is to fill this gap. We will cast some doubts on whether the dispositionalist really is in a better position to explain our modal knowledge. In fact, we argue that there is a tension between some core tenets of a powers metaphysics and the very features that make dispositionalism the ideal backdrop for a desirable epistemology of modality. We conclude that this leaves dispositionalists who want to deliver the promised epistemology with a hard, currently unfulfilled, task.

Recently, Ioannidis, Livanios, and Psillos (2021) have argued that powers and laws play different explanatory roles, and both are needed to explain the regularities in a metaphyiscally robust fashion. They argue that existing governing laws and powers views are fatally flawed and lack the resources to offer a satisfactory explanation of the regularities. They develop a hybrid theory, which they call the Dualist Model (DM), in which both powers and governing laws play a distinctive explanatory role. They claim that such a dualist view combines all the virtues, and shares none of the vices, of standard non-Humean theories. In this paper I examine the Dualist Model, and assess whether such a hybrid position is indeed preferable. I will argue that the theory does not fare better than canonical powers nor governing laws views –– at least, with regard to the desiderata set out by Ioannidis, Psillos, and Livanios themselves. On the contrary, I will argue that DM inherits all the problems that they attribute to classic powers and governing laws views.

Dispositionalism is the view that it is possible that p iff sometimes, something has an iterated potentiality to be such that p. Recently a formidable challenge has been raised against it: the paradox of necessary perfect masks (Vetter & Busse 2022). A mask is perfect if it guarantees that, come what may, the manifestation will not come about as long as the mask is present, and it is necessary if it cannot be removed or destroyed. This generates a contradiction for Dispositionalism. In this paper, I offer a novel solution to the paradox, which I call the Degree Solution. As the name suggests, it is centred around the role that degrees of potentiality play in grounding modality. My strategy to dispel the paradox comprises of three steps. First, I will argue that degrees of potentialities play a role in grounding modal truths: only non-zero potentialities ground modal truths. Then, I will argue that that degree of potentialities are extrinsic second order properties of potentialities –– and, in particular, that they depend on the modal status of both their stimuli/disposition partners and masks. I will argue that necessary perfect masks reduce the degree of a potentiality to zero, thereby preventing them from grounding a modal truth and preventing the contradiction to arise. Thirdly, I argue that there are zero-degree potentialities, that they are not ad hoc and have genuine explanatory power. They offer the theory important expressive resources to make sense of our intuitions concerning cases of ‘impossible dispositions’ (Jenkins & Nolan 2013) and perhaps also the resources to account for the truth and falsity of some non-vacuous counter-possible and counter-nomic conditionals. Necessary perfect masks are not the ‘big bad bug’ of dispositionalism. On the contrary, taking them seriously leads us to discover new and welcome features of the theory.

Dispositions come in degrees. Powers theorists have suggested that this is explained by the fact that powers come in degrees, too. Degrees of powers have usually been characterised in terms of the robustness of the modal connection between power, stimulus, and manifestation. However, modal strength cannot account for all our comparative judgements between dispositions. In this paper, I argue that there is also a different kind of degrees of powers, which I dub intensity. Intensity is connected to the relation between the magnitude of stimuli and manifestations. I first develop a number of models for intensity degrees; then, I argue that intensity is conceptually independent from modal strength, and that it can do important explanatory work.

Dispositionalism is the theory of modality according to which all (metaphysical and natural) modal truths are made true by some actual irreducibly dispositional property. The relationship between Dispositionalism and time is yet to be satisfactorily explored. In this paper we contribute to this task by examining how Dispositionalism deals with ‘dated truths’: propositions involving a specific time, e.g. “It might rain at 12.30”. We examine two possible accounts: the first, 'Dated Manifestations Strategy', is the idea that powers are very fine-grained, and tend towards temporally very specific manifestations. We argue that such strategy should not be adopted, for it leads to unnecessary violations of ontological parsimony; it is unable to accommodate an ontology of platonic universals; and it is incapable of offering a principled explanation of the forward-looking nature of powers. We offer an alternative account, the "Duration Strategy", which relies on an independently determined arrow of time and the existence of some “duration facts” that specify how long a power takes to bring about its manifestation. We argue that the Duration Strategy is to be preferred. We then flesh out the account by exploring the connection between powers, duration facts, and processes.

Vetter (2015) develops a localised theory of modality, based on potentialities of actual objects. Two factors play a key role in its appeal: its commitment to Hardcore Actualism, and to Naturalism. Vetter’s commitment to Naturalism is in part manifested in her adoption of Aristotelian universals. In this paper, we argue that a puzzle concerning the identity of unmanifested potentialities cannot be solved with an Aristotelian conception of properties. After introducing the puzzle, we examine Vetter’s attempt at amending the Aristotelian conception in a way that avoids the puzzle, and conclude that this amended version is no longer to be considered naturalistic. Potentiality theory cannot be both actualist and naturalist. We then argue that, if naturalism is to be abandoned by the actualist, there are good reasons to adopt a Platonist conception of universals, for they offer a number of theoretical advantages and allow us to avoid some of the problems facing Vetter’s theory.

Dispositionalism is the theory of modality according to which all (metaphysical and natural) modal truths are made true by some actual irreducibly dispositional property. The relationship between Dispositionalism and time is yet to be satisfactorily explored. In this paper we contribute to this task by examining how Dispositionalism deals with ‘dated truths’: propositions involving a specific time, e.g. “It might rain at 12.30”. We examine two possible accounts: the first, 'Dated Manifestations Strategy', is the idea that powers are very fine-grained, and tend towards temporally very specific manifestations. We argue that such strategy should not be adopted, for it leads to unnecessary violations of ontological parsimony; it is unable to accommodate an ontology of platonic universals; and it is incapable of offering a principled explanation of the forward-looking nature of powers. We offer an alternative account, the "Duration Strategy", which relies on an independently determined arrow of time and the existence of some “duration facts” that specify how long a power takes to bring about its manifestation. We argue that the Duration Strategy is to be preferred. We then flesh out the account by exploring the connection between powers, duration facts, and processes.

Establishing Dispositionalism as a viable theory of modality requires the successful fulfilment of two tasks: (i) showing that all modal truths can be derived from truths about actual powers, and (ii) offering a suitable metaphysics of powers. These two tasks are intertwined: difficulties in one can affect the chances of success in the other. In this paper, I generalise an objection to Dispositionalism by Jessica Leech and argue that the theory in its present form is ill-suited to account for de re truths about merely possible entities. I argue that such difficulty is rooted in a problem in the metaphysics of powers. In particular, I contend that the well-known tension between two key principle of powers ontology, namely Directedness (all powers are “for” their manifestation) and Independence (some powers might fail to bring about their manifestation) has received an unsatisfactory solution so far, and that it is this unsatisfactory solution concerning the status of “unmanifested manifestations” that makes it hard for Dispositionalism to account for mere possibilia. I develop a novel account of the status of unmanifested manifestations and an overall metaphysics of powers which allows to better respond to Leech's objection and handle mere possibilia. The central idea of the proposal is that unmanifested manifestations are akin to mere logical existents, and are best characterised as non-essentially non-located entities.

Dispositionalism is the theory of modality that grounds all modal truths in powers: all metaphysically possible and necessary truths are to be explained by pointing to some actual power, or absence thereof. One of the main reasons to endorse dispositionalism is that it promises to deliver an especially desirable epistemology of modality. However, so far this issue has not be fully investigated with the care it is due. The aim of this paper is to fill this gap. We will cast some doubts on whether the dispositionalist really is in a better position to explain our modal knowledge. In fact, we argue that there is a tension between some core tenets of a powers metaphysics and the very features that make dispositionalism the ideal backdrop for a desirable epistemology of modality. We conclude that this leaves dispositionalists who want to deliver the promised epistemology with a hard, currently unfulfilled, task.

In this paper I argue that even the most radical metaphysics of powers (such as that adopted by Mumford and Anjum, Cartwright, or Groff) are compatible with eternalism. I first offer a taxonomy of powers ontologies, and attempt to characterise the difference between moderate and radical powers ontologies—the latter are characterised by an emphasis on _production_ and _dynamicity_. I consider an argument by C. Friebe to the effect that the productive character of powers is inconsistent with Eternalism and find it wanting. I then elucidate the notion of _dynamicity_ that radical powers theorists employ by making apparent their link with an ontology of irreducible processes. Finally, I respond to an argument by Donatella Donati to the effect that eternalism entails a reductive account of change which is inconsistent with process ontologies, and show that the the two are compatible. I conclude that we have no reason to think that radical powers metaphysics (and, a fortiori, every powers ontology) are not compatible with eternalism.

There is a tension between Dispositionalism––the view that all metaphysical modality is grounded in actual irreducible dispositional properties––and the possibility of time travel. This is due to the fact that Dispositionalism makes it much harder to solve a potentiality-based version of the grandfather paradox. We first present a potentiality-based version of the grandfather paradox, stating that the following theses are inconsistent: 1) time travel is possible, 2) powers fully ground modality, 3) self-defeating actions are impossible, 4) time-travellers retain their intrinsic powers upon time-travelling, and 5) time-travellers are ordinary agents with basic intrinsic potentialities. We then consider a number of potential solutions, and find them wanting. We argue that the metaphysical impossibility of performing a self-defeating action acts as a necessary perfect mask––while time-travel lets us “slip” the potentiality under the mask, thus generating the contradiction. We conclude considering what are the options for the dispositionalist.

In this paper we examine whether and how powers ontologies can back formal causation. We attempt to answer three questions: i) what is formal causation; ii) whether we need formal causation, and iii) whether formal causation need powers and whether it can be grounded in powers. We take formal causal explanations to be explanations in which something's essence features prominently in the explanans. Three kinds of essential explanations are distinguished: constitutive, consequential, and those singling out something's propria. This last kind of explanation has been somewhat overlooked in the literature, but we argue that it features in much of the most relevant uses of formal explanations in philosophy and science. These are the explanations for why an object has certain propertis that are not, properly speaking, parts of its essence, but that belong to it more intimately than just being part of its consequential essence: they are the properties that ‘flow’ from something's essence. It is argued that a powers metaphysics is uniquely placed to make sense of this last phenomenon. We then distinguish three grades of involvement in which powers might be salient for formal causal explanations: i) powers might be the subject matter of the essence operator, ii) the essence of something might include (or be exhausted) by powers, or iii) powers can explain how propria can flow from something's constitutive existence.

In this paper I argue that even the most radical metaphysics of powers (such as that adopted by Mumford & Anjum, Cartwright, or Groff) are compatible with eternalism. I first offer a taxonomy of powers ontologies, and attempt to characterise the difference between moderate and radical powers ontologies – the latter are characterised by an emphasis on production and dynamicity. I consider an argument by C. Friebe to the effect that the productive character of powers is inconsistent with Eternalism and find it wanting. I then elucidate the notion of dynamicity that radical powers theorists employ by making apparent their link with an ontology of irreducible processes. Finally, I respond to an argument by Donatella Donati to the effect that eternalism entails a reductive account of change which is inconsistent with process ontologies, and show that the the two are compatible. I conclude that we have no reason to think that radical powers metaphysics (and, a fortiori, every powers ontology) are not compatible with eternalism.

In this dissertation, I develop a metaphysics of powers to ground Dispositionalism, the theory of the source of modality according to which all alethic modal truths are grounded in dispositional properties instantiated in the actual world. I consider a number of key theses that powers metaphysics display, and investigate which can be incorporated in the metaphysical base of Dispositionalism, and how. In the first part I examine the interaction of two core principles of powers ontologies: Directedness, the thesis that powers ‘point at’ their manifestations, and Independence, the thesis that powers can fail to manifest. These two principles are in tension: there is an argument, known as Too Much Possibility, to the effect that they are inconsistent. I examine various strategies to resist the argument. These involve Physical Intentionality, numerical identity between power and manifestation, process ontologies, and platonic universals. I conclude that they are all unsatisfactory. In the second part, I develop a ‘minimal metaphysics of powers’ that is immune from the threat of Too Much Possibility. This involves considering unmanifested manifestations to be akin to Mere Logical Existents. I argue that the best way to avoid the tension at the heart of powers ontologies is to conceive of unmanifested manifestations as non-essentially non-spatiotemporally located entities. I then consider some consequences of minimal metaphysics: I examine which ontological category the manifestations of power can belong to, and what are the prospects of grounding metaphysical, as opposed to natural, modality. Finally, in the third part, I investigate whether further key theses of powers ontologies can be incorporated into the minimal metaphysics. This leads to discuss the relationship of the minimal metaphysics with grounding and dependency relations, the metaphysics of time, the truthmaking principle, and tendential theories of powers.