Causation has been at the center of philosophical and scientific debates throughout the history of Western thought. The contemporary debate features two main opposing views. On the one side there is neo-Humeanism, the viewpoint championed by David Lewis according to which objects have causal powers in virtue of the distribution in space-time of the fundamental, intrinsic and categorical physical properties, and the (contingent) laws of nature that supervene on that distribution. This view traces back to David Hume’s skeptic and reductionist take on causation, and in different forms have been widely accepted for the past three centuries. On the other side there is neo-Aristotelianism, according to which objects have properties that are essentially causal (or even, objects are built out of properties that are essentially causal). Causation is the exercise of causal powers. This view traces back to Aristotle’s notions of potentiality, actuality, and essence. The past two or three decades have witnessed a very much increased interest in the neo-Aristotelian view; while the metaphysics of powers has been much developed, its applications also in various domains of philosophical inquiry have been intensely explored.Footnote 1 This special issue looks at how the metaphysics of powers can be fruitfully applied to several major problems in the contemporary philosophy of mind. Many questions in philosophy of mind are still open. For instance, just to name a few: what is the metaphysical relationship between consciousness and the physical? Are phenomenal properties reducible to physical properties, fundamental, or emergent? How are we to explain notions such as belief, agency, and free will? In this issue we collected a variety of answers to these and other questions, all characterized by a focus on the metaphysical notion of powers. We have organized the contributions into five groups. The first includes two articles devoted to mental powers and their relation to metaphysical emergence (Carruth and Paolini Paoletti); the second includes two articles focused more directly on the relation between powers and conscious experience (Gozzano and Yates); the third includes four articles investigating the relevance of powers in the contemporary debate on panpsychist Russellian monism (henceforth RM) (Mørch, Goff, Chan, and Klinge); the fourth includes two articles that explore in more detail the application of neo-Aristotelian hylomorphism to the philosophy of consciousness (Owen and Jaworski); and the last includes four articles devoted to exploring power-based accounts of agency, free will, belief, and affordances (Frost, van Miltenburg and Ometto, Koziolek, and Vetter).

In “Emergence, reduction and the identity and individuation of causal powers”, Alex Carruth argues that the debate between emergentism and reductionism about the mind can be settled by means of (or at the cost of—opponents might want to say) metaphysical emergence or strong emergence, namely the view that emergent entities have novel causal powers that are irreducible to the causal powers of their constituents. Carruth then proceeds to characterize the notion of causal powers at work within this account of emergence by focusing on two main questions about their nature: do powers have a single manifestation type (single-track) or multiple manifestation types (multi-track)? And, secondly, do powers manifest when triggered by a suitable stimulus, or do they act as mutual manifestation partners? Different answers to these questions yield different accounts of causal powers; which Carruth assesses for their pros and cons. Carruth proceeds to evaluate the bearing of these four views on the emergence-reduction debate, concluding that accepting in one’s ontology multi-track powers undermines the warrant for positing strong emergence; while single-track powers triggered into action by a stimulus support it.

In “Emergent powers”, Michele Paolini Paoletti maintains that the metaphysical emergence is best construed in terms of causal powers rather than other sorts of notions, and defends this view comparing it to alternative accounts of emergence. Paolini Paoletti defends a view of strongly emergent powers as all and only those powers that are possessed in virtue of lower-level powers, but that cannot be activated by any lower-level power nor lower-level condition. Paolini Paoletti proceeds to show that this view has advantages over other rival ones thanks to its capacity to account for the fact that emergent powers are both dependent on the emergence basis (for instantiation) and also independent from it (in their being novel).

In “The dispositional nature of phenomenal properties”, Simone Gozzano engages with the question of whether phenomenal properties might be best understood as powers. First, Gozzano shows that the view that phenomenal properties are categorical is incoherent. The incoherence rests on the categoricalist assumption of Humility, the view that knowing the causal role of properties does not allow us to know the nature of the properties that play those roles. However, as already remarked by Kripke and Lewis, in the case of phenomenal properties, epistemology and ontology coincide: what one knows is what there is. From this follows the inconsistency of phenomenal categoricalism. Departing from a categoricalist view of phenomenal properties, Gozzano defends the view that phenomenal properties are dispositions essentially defined by their manifestation, a characteristic feeling, and whose causal profile is fixed across possible worlds. Gozzano concludes by showing that we need not and should not hold Humility, and how pandispositionalism represents a promising option for a physicalist view of phenomenal properties.

In “Neural synchrony and the causal efficacy of consciousness”, David Yates proposes a power-based physicalist account of consciousness aimed to overcome the causal exclusion problem. In this proposal, phenomenal properties are dependent powerful qualities, i.e., properties that have their causal roles in virtue of being the qualities they are, without inheriting powers from their realizers. With the aid of this metaphysical notion and a discussion of evidence from neuroscience, Yates argues that phenomenal properties are representational contents realized by neural synchronous oscillation, and as such can be construed as broadly physical, multiply realizable qualities which bestow novel causal powers to their basic physical realizers.

In “Does dispositionalism entail panpsychism?”, Hedda Hassel Mørch investigates an evident clash between Russellian monism and power metaphysics: according to the former, phenomenal properties are the categorical grounds of physical powers, whilst for the latter, powers are irreducible and do not need categorical grounds. Mørch offers a defense of mental dispositionality, the claim that phenomenal properties are the only fundamental dispositional properties we know or can positively conceive of. Mørch supports this thesis focusing on motivational phenomenal properties such as pain and pleasure, and claims that in combination with other premises, this view shows that dispositionalism entails panpsychism.

In “Revelation, consciousness+, and the phenomenal powers view”, Philip Goff continues the discussion of the causal efficacy of phenomenal properties focusing on Revelation, the thesis that we have introspective access to the essential nature of our conscious states, and the problematic consequence that revelation leads to an argument for epiphenomenalism. In contrast with Mørch’s view (previous chapter in this issue), Goff argues for the consciousness+ view, according to which experiences such as pain are only aspects of a more expansive property (in this case pain+) that has both phenomenal and non-phenomenal aspects, and shows how this view is able to resist the argument for epiphenomenalism by acknowledging that phenomenal properties do make a causal contribution but only as part of consciousness+ states.

In “Can the Russellian monist escape the epiphenomenalist’s paradox?”, Lok-Chi Chan discusses an objection to RM based on the paradox of phenomenal judgement: if qualia are epiphenomenal, then any judgement concerning qualia cannot be caused by (the possession of) qualia. Chan starts off by discussing the shortcomings of epiphenomenalism and the purported advantages of RM as discussed by Chalmers (1996) and Seager (2009); and puts forward a new argument, the Zombie Bases Argument, to show how a similar objection can be raised for RM, with a twist: while according to RM qualia possess powers, the Zombie Bases Argument shows that those powers are not connected to their categorical basis in such a way that our phenomenal judgments would be sensitive to the difference between qualitative bases and zombie bases. After addressing some potential counterarguments, Chan concludes that RM does not escape the paradox of phenomenal judgement, and therefore is in no better shape in this respect than epiphenomenalism.

In “The role of mental powers in panpsychism”, Fabian Klinge proposes a modified version of RM aimed to overcome three traditional problems that afflict it: the combination problem, the causal exclusion problem, and the structural exclusion problem. After introducing the three problems, Klinge discusses the shortcomings of Mørch’s phenomenal powers panpsychism with respect to the latter: for Klinge, the assumption that micro qualia act as categorical bases for microphysical dispositions renders Mørch’s view incapable of avoiding the structural exclusion problem. The author then proceeds to present a version of impure Russellianism in which microphenomenal states are embedded in relations to two additional types of dispositions. Klinge argues that a solution to the structural exclusion problem requires the existence of microintentions, and that by allowing for a specific type of mental-to-mental downward causation, the existence of microintentions provides emergent panpsychism with a solution to the causal exclusion problem too.

In the article titled “Aristotelian causation and neural correlates of consciousness”, Matthew Keith Owen presents an explanatory model of neural correlates of consciousness (NCC) informed by Aristotle’s and Aquinas’ hylomorphic views on soul and causation. Owen builds on the Aristotelian distinction between active and passive powers to formulate the central claim of neo-Thomistic hylomorphism, according to which mental powers (of the soul) and physical powers (of the body) are interdependent partner-powers, and the manifestation of active powers of either kind ontologically depends on the manifestation of passive powers of the other kind. After characterizing the notion of mind–body powers in more details, Owen argues that such an account explains the consistent regularities of NCC across human species by virtue of the metaphysical relation between type of form and biological/structural organization. Finally, the author delineates the Mind–Body Powers Model of the NCC, according to which NCC are explained by the interdependence of the mental and bodily powers co-manifested via the conscious state and its neural correlate.

In “Hylomorphism and the construct of consciousness” William Jaworski defends the thesis that the hard problem of consciousness rests on an implicit theoretical commitment that is incompatible with hylomorphism. Consequently, he maintains, if hylomorphism is true, there is no hard problem of consciousness. Jaworski’s starting point is the idea that at least some things in the world are composed of matter with a specific configuration or structure. After introducing the notions of structured activities and enactive perception, the author offers a hylomorphic account of phenomenal character, and explores how it differs from physicalism, its implications for the notion of explanation, and some objections. Building on the proposed version of hylomorphism, Jaworski maintains that phenomenal experience is a kind of structured activity that can be exhaustively accounted for in terms of (i) the powers of conscious beings, (ii) the subsystems in which those powers are embodied, and (iii) the kind of coordination or structure that unifies the activities of those subsystems into conscious events.

In “What could a two-way power be?”, Kim Frost engages with the question of whether the notion of two-way powers can be used to distinctively characterize free agents. “Two-way power” is a medieval term that refers to the Aristotelian view of powers that have two different kinds of exercise/manifestation; for instance, in the case of agency, the power to act can be exercised by acting or by refraining from acting. Frost raises a dilemma for two-way powers: either the two manifestation-types are similar enough to be captured by a unified description, and therefore two-way powers are really one-way powers; or they are not, but then two-way powers seem to reduce to a combination of one-way powers: one for each manifestation-type. Frost provides a solution to the dilemma based on Aristotle’s notion of rational powers and on the rejection of canonicalism (the view that equates exercising a power with doing what the power is specified as a power to do) that results in a novel view of agency as a two-way power that implies a (causal) power to do and a (non-causal) power to refrain, accompanied by the self-conscious understanding of the significance of refraining.

In “Free will and mental powers” Neils van Miltenburg and Dawa Ometto contribute to an ongoing discussion concerning what distinguishes the power to act from other powers; and well complement Frost’s essay in this volume. Van Miltenburg and Ometto begin by identifying difficulties of which existing agent-causal accounts are prey, and argue that, notwithstanding some theoretical advantages, characterizing the power to act as a two-way power does not capture the rational nature of the power to act. The authors argue that the peculiar self-determining character of the power to act is a consequence of its intrinsically rational nature, which includes self-conscious activity. Contra O’Connor (2005) and Lowe (2013), the authors claim that the agent’s knowledge and reasons are not just part of the set-up within which the power to act is exercised; rather the activity of making up one’s mind in practical reasoning coincides with exercising the power to act.

In “Belief as the power to judge” Nicholas Koziolek defends a novel type of dispositional approach for which belief is the power to judge. Koziolek begins with positing the ignorance principle, i.e., the claim that it is possible to believe the premises of an obviously valid inference without believing its conclusion. For the author, dispositionalism has the resources to provide an elegant explanation for the truth of the ignorance principle; not however in its standard or classical formulation. Koziolek argues that classical dispositionalism faces a dilemma: by characterizing belief as a disposition (say, to behave in a particular way), it either fails, or it entails anti-realism about belief. The author’s proposed solution is to combine dispositionalism with two theses concerning belief. Firstly, belief is a power that has its causal-explanatory powers essentially and in virtue of which one is disposed to behave in a particular way (rather than the disposition itself). Secondly, belief is the power to judge, where judgement is defined in terms of epistemic acts (and their components). Koziolek concludes that this theory of belief can both explain the truth of the ignorance principle and secure the fact that belief has some of its causal-explanatory powers essentially.

In “Perceiving potentiality: a metaphysics for affordances” Barbara Vetter proposes a power-based account of affordances, the notion introduced by James J. Gibson to refer to “what things furnish, for good or ill.” (Gibson 1979). Part of the debate on ecological psychology is focused on the question whether we perceive affordances (Reed 1996; Nanay 2011). In this paper, Vetter starts from the assumption that we do, and asks the further and deeper question: what exactly are affordances? Vetter begins by setting out four desiderata for any sound account of affordances and by giving a sketch of the anti-Humean view of dispositions that will be used. The two are then conjoined to provide a view of affordances as (a species of) potentialities that satisfy the four desiderata: (i) affordances entail real possibilities, (ii) are objective features, (iii) depend (in part) on abilities and dispositions of the individual, and (iv) must be perceivable (and are typically perceived in successful affordance perception). In light of this positive result, Vetter claims that associating anti-Humeanism and affordance-based theory of perception is beneficial for both views: on one hand, the notion of affordances is beneficial to dispositionalism in showing that knowledge of dispositions has a solid empirical basis in perception itself; on the other hand, dispositionalism provides independent grounds to believe in the existence of potentialities, of which affordances are a species, and allows us to accommodate both relational and non-relational views of affordances within a single anti-Humean framework.