The Agency Theory of Causality and the Context Dependence Issue

As we have seen in the previous section, many authors have stressed the context dependence of levels that had already been clearly indicated by the new mechanist philosophers, especially by Craver. In almost all cases, the context dependence has been connected with an interventionist account of causality.

Perhaps with some oversimplification, it is now customary to distinguish two types of an interventionist theory of causation: the agency theory, which is usually attributed to Peter Menzies and Huw Price, and the manipula- bility theory, usually ascribed to Daniel Hausman and James Woodward (see, for example, Menzies (1989); Menzies and Price (1993); Price (1991), (1992), (2007); Hausman (1997), (1998); Hausman and Woodward (1999); Woodward (2003), (2011)). We agree that the adoption of Woodward’s interventionist theory of causality yields a picture of scientific practice that is more realistic than the other accounts of causality may ever expect to achieve. However, in spite of the unquestionable merits of Woodward’s theory, we cannot agree with its separating the notion of causality from that of human intervention. For this reason, we shall adopt in our approach a particular development of the agency theory of von Wright, Price and Menzies, according to which the close link between intervention and causality cannot be understood without reference to the free agency of human beings.² In this section, we shall very briefly sketch how this account does justice both to the linguistic-pragmatic and to the objective-ontic factors of causal imputation, both of which are necessary in order to identify mechanisms, levels and components in a context-relative way.

According to the Agency Theory of Causality, the notions of cause and effect depend essentially on our ability to intervene in the worlds as agents. As von Wright expressed it: “It is established that there is a causal connection between p and q when we have satisfied ourselves that, by manipulating the one factor, we can achieve or bring it about that the other is, or is not, there. We usually satisfy ourselves as to this by making experiments” (von Wright 1971: 72; see also von Wright 1989).

One of the most marked traits of the agency theory of causation is its connection with any “pragmatic” theory of scientific explanation. However, the relativity of causal imputations and explanations to our practical interests and values does not exclude objectivity and invariance, avoiding some criticism that agency theory of causation has raised. That is, the relativity of causal imputations is fully compatible with a specific objective or, in Salmon’s terms, “ontic” interpretation of causality. It is, in fact, well known that any given phenomenon is preceded by an infinite number of events or conditions, each one of which can be said to be its cause. To take a well-known example in the literature, all the conditions connected to the lighting of a match are, properly speaking, co-causes of that event: the match must not be wet; one must apply the right pressure; the rough surface on which one rubs the match must be in good condition and not too worn; the external temperature must not be under a certain threshold, etc. Similarly, a cold is not caused by the virus alone, but also by factors such as the climate, the state of the patient’s immune system, the patient’s previous history, an environment that is not lethal for the virus etc. (e.g., Gardiner 1952: part 1, chapter 2). This is sometimes called the “parity argument,” and it is generally considered a fundamental problem for the interventionist theory of causation (see Waters 2007), but the agency theory’s framework is actually able to grasp and usefully distinguish causes from concomitant conditions in the process of scientific understanding.

In fact, what is or is not considered the cause of an event depends on the agent’s adopted point of view, which is closely connected to his values and practical possibilities. Without values and concepts that guide our actions and confer meaning to them, we would be unable to make any causal imputations in the vast sea of reality where everything interacts with everything else, and consequently we would be unable to formulate any laws of nature. Not all of an event’s infinite causes have an equal claim to being its cause: we usually take into consideration only one or some of its causes, namely those that are relevant to our purposes and that we believe are, in principle, changeable. For the camper who wants to light a fire, the fact that the match is damp is regarded as more important than the chemical composition of the match’s head, because it is more easily changeable. For this reason, humidity, rather than chemistry, is normally held to be the contextually decisive cause of the failure to light camp fires.

However, the choice between the various conditions of an event is not haphazard or arbitrary. It is governed by rules or reasons that, in principle, can be reconstructed and appropriated in the first person by any owner of a body and a mind. On the one hand, cause and effect are certainly our concepts, i.e. human constructs dependent on our cognitive interests. On the other hand, they are made in order to grasp and dominate reality. The fact that we make these concepts in view of our theoretical interests and practical possibilities does not exclude the objective reality of the causal processes that they serve to bring to light. And that for two reasons: first, because the pragmatic context in which an agent, guided by her/his practical interests and by his/her knowledge about the situation in which she/ he finds himself is an objective and independently existing reality; second, because the objectivity of scientific explanations and the independence of reality (including causal relations) from the epistemic subject are closely connected with the concepts and values through which the subject regards reality: once these have been fixed, what is known is independent of us just because it is a part of reality. The particular interests and practical possibilities of intervening in the situation in which the camper finds himself may lead him to consider humidity, rather than chemistry, to be the cause of the failure to light camp fires, but there is no desire or preference or choice which can change the causal laws of nature connecting the phenomena of humidity and combustion.³

Now, this context dependence of causality, if it is combined with a pragmatic-experimental notion of “mechanism,” connects the heuristic aspect of levels highlighted by Craver (cf. Section 1) with the context dependence developed by Mitchell. In our opinion, the agency theory of causation easily avoids naive and incoherent concepts of levels of explanation in biology, because of its ability to accurately distinguish between the linguistic- pragmatic and the objective-ontic factors of causal imputation. In particular, the agency theory of causation has the epistemological tools to answer Eronen’s recent criticism of the mechanist concepts of “level” and “component” (Eronen 2013, 2015). As we shall see, this objection does not present a difficulty for Craver and most of the other mechanist philosophers, to the extent that a context-dependent, but not relativistic, notion of mechanism, level and component is consistently held.