Online research in philosophy

The aim of this paper is to argue that there are categorical properties as well as causal powers, and that the world would not exist as we know it without them. For categorical properties are needed to define the powers—to locate them, and to specify their laws of action. These categorical properties, I shall argue, are not dispositional. For their identities do not depend on what they dispose their bearers to do. They are, as Alexander Bird would say, ’quiddities’. But there is nothing wrong with quiddities. And, in the second half of this paper, I shall defend the thesis that all categorical properties are quiddities.

Standardly, mental properties like beliefs, desires, fears, etc. are analysed as relations between the agent, to whom the predicate is ascribed, and a proposition, which is the intentional content of this property. According to this relational analysis, having a thought implies having its content present to the mind. This has wide-ranging philosophical implications, e.g. for the possibility of children and animals having intentional mental properties, or for the problem of knowing one’s own thoughts. Further, according to the relational analysis, the causal efficacy of mental properties must be in virtue of their content. This implies that folk-psychological explanations acquire a special status, for they employ mental properties as the explanans of behaviour. Mental properties can be conceived of as causally efficacious, and hence like standard scientific explanans, only if a satisfactory account is provided how they are causally efficacious in virtue of their semantic content. A successful account of this sort, I submit, does not exist as of yet; hence it seems, on the relational account, that folk psychological explanations are non-scientific, if they are explanations at all.

Sydney Shoemaker’s ‘Subset Account’ offers a new take on determinable properties and the realization relation as well as a defense of non-reductive physicalism from the problem of mental causation. At the heart of this account are the claims that (1) mental properties are determinable properties and (2) the causal powers that individuate a determinable property are a proper subset of the causal powers that individuate the determinates of that property. The second claim, however, has led to the accusation that the effects caused by the instantiation of a determinable property will also be caused by the instantiation of the determinates of that property—so instead of solving the problem of mental causation, the Subset Account ends up guaranteeing that the effects of mental properties (and all other types of determinable property) will be causally overdetermined! In this paper, I explore this objection. I argue that both sides in this debate have failed to engage the question at the heart of the objection: Given that both a determinable property and its determinates have the power to cause some effect (E), does it follow that both will actually cause E when the relevant conditions obtain? To make genuine progress towards answering this question, we need to take a serious look at the metaphysics of causation. With the debate properly reframed and issues about the metaphysics of causation front and center, I explore the question of whether the Subset Account is doomed to result in problematic causal overdetermination.

The view that properties have their causal powers essentially, which I will here call property essentialism, has advocates in Chris Swoyer,[1] Sydney Shoemaker [2], Alan Chalmers [3], Brian Ellis [4] and Caroline Lierse [5], among a few other authors in recent literature. I am partial to this view as well and I will shortly explain the grounds I find compelling in favor of it. However, we will also see that the essentialist view of properties and laws does not adequately do quite so much as might be hoped. Property essentialism has the straightforward result that at least causal laws are metaphysically necessary. A natural view of such laws is that they are analyses of the essential nature of basic properties in terms of their essential causal powers. Brian Ellis proposes that conservation laws and other laws that may not be exactly causal are best thought of as characterizing the essential properties of worlds. But this further essentialist thesis is not directly relevant to the issues I want to address here.

Owens (1993) argues that one cannot accept the anti-individualistic conclusions of arguments inspired by Twin Earth thought experiments and still maintain that folk psychological states causally explain behavior. Saidel (1994) has argued that Owens' argument illegitimately individuates the contents of folk psychological states widely and causal powers narrowly. He suggests that causal powers may well be wide, and that the conditions that militate in favor of wide content also militate in favor of wide causal powers; mutatis mutandis for narrow content and narrow causal powers. I argue that these suggestions are in error, and hence that Saidel's criticism is ineffective. Owens' original point is therefore likely to stand.

One of several problems concerning the possibility of mental causation is that the causal potential of a supervenient property seems to be absorbed by its supervenience base if that base and the supervenient property are not identical. If the causal powers of the supervenient property are a proper subset of the causal powers of the supervenience base then, according to the causal individuation of properties, the supervenience base seems to do all the causal work and the supervenient property appears to be futile. Against this consequence it is possible to argue, first, that the relevant properties of causes must be in some sense proportional to the relevant properties of their effects and, second, that the principle of causal closure serving as a premise in the supervenience argument is probably false. The constraint that the relevant properties of causes should be proportional to the relevant properties of their effects together with the falsity of the closure principle leads to a restoration of the causal efficacy of supervenient properties.

Sydney Shoemaker has attempted to save mental causation by a new account of realization. As Brian McLaughlin argues convincingly, the account has to face two major problems. First, realization does not guarantee entailment. So even if mental properties are realized by physical properties, they need not be entailed by them. This is the first, rather general metaphysical problem. A second problem, which relates more directly to mental causation is that Shoemaker must appeal to some kind of proportionality as a constraint on causation in order to avoid redundant mental causation. I argue that, in addition, a “piling problem” arises, since causal powers seem to be bestowed twice. Then, I try to sketch an alternative view of the relation between causal powers and properties—a reductionist view—which fares better on some accounts. But it may have to face another and, perhaps, serious problem, the “problem of the natural unity of properties”. Finally, I will pose a question about the relation between causal powers and causation.

In discussions on mental causation and externalism, it is often assumed that extrinsic, or relational, properties cannot have causal efficacy. In this paper I argue that this assumption is based on a category mistake, in that causal efficacy (dependence among events or states of affairs) is confused with causal influence (persistence of and interaction among objects). I then argue that relational properties are indeed causally efficacious, which I explain with the help of Dretske's notion of a 'structuring cause'.