Powers

Causal properties are dispositional (rather than categorical) and dispositions are powers: ‘a power is essentially a disposition to do something’ (Mumford 2009, 96). Therefore, ‘Dispositional monism is the view that natural properties and relations are “pure powers”’ (Bird 2007, 513).

Among the new dispositionalists^[146] we find two positions on the dispositional nature of properties. Authors such as Mumford hold that all properties are dispositional (a view which Molnar 2003 has called‘pandispositionalism’). But other authors, such as Ellis, disagree arguing that there are some properties that are not dispositional. Specifically, they do not consider geometric and structural properties to be dispositional. Thus, they divide properties into two types: dispo­sitional and non-dispositional.

The new dispositionalists do agree that the relations between properties and causal powers are real, not merely analytical. The natural properties that exist in the world include a series of causal powers which are dispositions or powers. Mumford (2011, 54) explains,‘Causes and powers are closely connected (...) A vase breaks when struck, for instance, because of its fragility, while sugar dissolves in water because it is soluble’. The idea is that an ontology of powers offers a good explanation of causality, something that was explored by earlier authors such as Bhaskar (1975), Salmon (1982), Harre and Madden (1975), among others.

Mechanisms were defined above as entities ‘doing something’.

Powers are the basic building block of a dispositional metaphysics. They are activated and interact to produce results. Transfer notion has place here since dispositionalism can be understood as a transfer theory insofar “causation will be the passing of the powers” (Mumford and Anjum 2013, 108). Therefore, the transference would not be as in the case of Salmon (1984, 133) energy, information, marks, signs and propensities. The theory of special relativity requires us to dis­tinguish between causal and pseudo causal processes. Causal processes are capable of transmitting energy, information, propensities, etc. pseudocausal processes are not. A car moving on the road is a causal process, it interacts with its surroundings in a number of ways, transmitting causal influence. Its shadow does not (Salmon 1984, 143).^[147] For Salmon, the basic causal mechanism is a causal process that transmits propensities.

While Salmon frames causality mainly in terms of a theory of propensities, Cartwright (1989, 2007a, b) defends a theory of capacities. At the heart of her theory lie causal capacities: C causes E because C has the capacity to do so, and this capacity is something that Cs carry with them from one situation to another (Cartwright 1989, 146).^[148] The property of being aspirin carries with it the capacity to relieve headaches. Capacities are closely related to powers, although Cartwright (2007a, 25) prefers the notion of capacities.^[149]

The new dispositionalists (Mumford, Ellis, Molnar, Chakravartty, Bird and Shoemaker, among others) prefer the concept of powers.

As Mumford (2009, 102) reminds us, ‘powers are the causes of their manifes­tations’. But the fact that a manifestation does not occur doesn’t mean that the powers (or capacities) are not there. The properties of nitroglycerine, and thus its powers, are in the pills even if they do not manifest, because nobody took them, for example, or someone took them along with another medication that blocks their manifestations. Powers do not have to manifest in order to exist; they are dispositions.

We must distinguish between the existence of a power (or capacity), its exercise and its manifest results:‘Dispositions can fail to manifest because of some inter­fering factors or because the conditions just happen not to be conducive’ (Mumford 2009, 95). The exercise of a power can produce manifest results but it also can be interfered with, causing the manifest results not to be produced. The main reasons why the results of a power may be interfered with are interactions, either between powers themselves or with other factors of the situation.

Therefore, finks or masks prevent the manifestations of a power from occurring in the circumstances in which they would normally be activated (Vihvelin 2004, Smith 2003, Fara 2008, Clarke 2009, and many others). Thus, ‘A poison’s power to kill when ingested can be masked by an ingested antidote. A glass’s fragility can be masked by internal packing that prevents breakage even if the glass is struck’ (Clarke 2009, 325). The gravitational pull between two celestial bodies can be completely masked because the pull from a third body, a nearby planet, for instance, is much stronger.

In the interaction between powers, one power can neutralise another, as when an acid and a base interact (as Cartwright (1989, 163) notes in her discussion of capacities). For example, in social sciences, the interaction between the power to adapt preferences to conditions (as in the case of sour grapes discussed by Elster) and the power for wishful thinking (preferring that which is beyond one's possi­bilities) can cancel the effects of the former, thus neutralising it. The interaction (in an individual) between the spillover effect (if a person follows a pattern of beha­viour P in X they will follow this same pattern of behaviour in Y) and the com­pensation effect (if a person does not follow a pattern of behaviour P in X they will not follow this same pattern of behaviour in Y) can be cancelled (both dispositions o powers).

The fact that the manifest results of an exercised power may not occur (when not interfered with) also depends on environmental circumstances. The exercise of the power (or set of powers) combined with other environmental factors is what explains this fact. The result may differ from one occasion on which the capacity is exercised to another.

All these facts strongly affect conditionality and pose important difficulties, even for the conditional reformulated by Lewis (1997), since he admits that the intrinsic properties which constitute the causal bases of powers are altered by the working of finks and masks. The fact that some dispositions are indeterminist also poses dif­ficulties for the conditional. In this case, even if there is no interference, the stimuli for the manifestation of a disposition do not guarantee that it will occur: ‘the stimulus might be present, the causal basis retained and all masks absent, and still the manifestation might or might not occur' (Clarke 2009, 326).

Therefore, even if a power (or disposition) has a universal type of manifestation, sometimes this manifestation may not occur. This means that causality, while universal, is not deterministic. Mumford (2009) holds that powers involve asui generis modality, and he therefore places powers somewhere between necessity and contingency: ‘The modal force of a power is neither entirely necessary nor entirely contingent but something in between' (Mumford 2009, 95). The existence of a power is not determined by its continuous explicitation in each of its manifestations.

However, the manifestations must take place once the interference is gone. Therefore, we can explain why a power does not manifest itself and, if possible, eliminate the interfering factor in order to demonstrate that if it were not for this factor the manifestations would occur, which means that the power exists even if it does not manifest itself.

For now, we are dealing with powers whose manifestations are sometimes cancelled out or masked by interactions with other properties or other factors of the situation. To assert a property is simply to say that a certain entity has the power to behave in a certain way, producing certain effects or manifestations if nothing prevents it from doing so.

Besides being relational, another interesting aspect of powers is that they work together with additive effects (and sometimes subtractive effects, as Mumford (2009) points out).^[152] Events are produced by powers working together, but also by powers acting against each other.

Therefore, the effect produced may vary, as it is the result of a set of powers, all of which contribute to its production. But this set of powers is not necessarily absolutely stable or fixed. One or more of the powers that make it up might change. Thus, power X, whose contribution has not changed, is present in the context of a set of powers in which there have been changes, and therefore the final effect produced by the set of powers is different from the one produced on other occa­sions. This is how a different event can be produced even if the contribution made by a particular power (but not the final result) always remains the same.

The notion of contribution, which emphasises both the individual and joint contributions of powers to the final result, was proposed by Mumford. In his words, ‘This contribution is what we have to equate with the power's manifestation' (Mumford 2009, 104). Therefore, it is not that the same power has different manifestations and causes different effects, but rather that insofar as these effects are produced by a set of powers, any change in this set translates to different or variable results. As in the case of distinguishing between the exercise of a power and its manifestation, to explain how the same power can be involved in the production of different results imply to account for why causality is not deterministic.

6