Johannes Persson

In this article I examine whether an influential theory of mechanisms proposed by Peter Machamer, Lindley Darden and Carl Craver can accommodate polygenic effects. This theory is both interesting and problematic, I will argue, because it ascribes a central role to activities. In it, activities are needed not only to constitute mechanisms but also to perform their causal role. These putative functions of activities become problematic in certain situations where several causes or elements of a mechanism contribute simultaneously, i.e. with certain forms of polygenic causation. The problematic form of polygeny, polygeny 2, occurs when the polygenic contribution concerns one and the same property or aspect of the affected object. When the result of such causation is that nothing happens, the theory suggested by Machamer and his colleagues cannot be applied. More generally, it seems that, whenever polygeny 2 is involved, the Machamer approach leads to an impoverished conception of mechanism

The thesis addresses the nature of causation. It is argued that causation exists and is as local as its causes and effects. As a consequence, the position advocated is contrary to the as yet prevailing view that no 'causal tie' between cause and effect exists. Moreover, it is suggested that this tie can be perceived. The essay attempts to elucidate the nature of causes, effects, and causal mechanisms. It is argued that they are facts rather than particulars or universals. Furthermore it is suggested that these facts can be conceived of as tropes. Finally, in the light of this thesis a few traditional issues are discussed: what is the relation between causation and explanation? How should we conceive of causal laws? Does the idea of mechanisms with different degrees of reliability further our understanding of the determinism/indeterminism issue?

Knowledge of factors that trigger human response to climate change is crucial for effective climate change policy communication. Climate change has been claimed to have low salience as a risk issue because it cannot be directly experienced. Still, personal factors such as strength of belief in local effects of climate change have been shown to correlate strongly with responses to climate change and there is a growing literature on the hypothesis that personal experience of climate change explains responses to climate change. Here we provide, using survey data from 845 private forest owners operating in a wide range of bio-climatic as well as economic-social-political structures in a latitudinal gradient across Europe, the first evidence that the personal strength of belief and perception of local effects of climate change, highly significantly explain human responses to climate change. A logistic regression model was fitted to the two variables, estimating expected probabilities ranging from 0.07 to 0.81 for self-reported adaptive measures taken. Adding socio-demographic variables improved the fit, estimating expected probabilities ranging from 0.022 to 0.91. We conclude that to explain and predict adaptation to climate change, the combination of personal experience and belief must be considered

Philosophers of science have often favoured reductive approaches to how-possibly explanation. This article identifies three alternative conceptions making how-possibly explanation an interesting phenomenon in its own right. The first variety approaches “how possibly X?” by showing that X is not epistemically impossible. This can sometimes be achieved by removing misunderstandings concerning the implications of one’s current belief system but involves characteristically a modification of this belief system so that acceptance of X does not result in contradiction. The second variety offers a potential how-explanation of X. It is usually followed by a range of further potential how-explanations of the same phenomenon. In recent literature the factual claims implied by the second variety have been downplayed whereas the heuristic role of mapping the space of conceptual possibilities has been emphasized. I will focus especially on this truth-bracketing sense of potentiality when looking closer at the second variety in the paper. The third variety has attracted less interest. It presents a partial how-explanation of X. Typically it aims to establish the existence of a mechanism by which X could be and was generated. The third conception stands out as the natural alternative for the advocate of ontic how-possibly explanations. This article transfers Salmon’s view that explanation-concepts can be broadly divided into epistemic, modal, and ontic to the context of how-possibly explanations. Moreover, it is argued that each of the three above-mentioned varieties of how-possibly explanation occurs in science. To recognize this may be especially relevant for philosophers. We are often misled by the promises of various why-explanation accounts, and seem to have forgotten nearly everything about the diversity of how-possibly explanations

Facts are once again put to work in philosophical enterprises. The discussion in this paper is conducted under the presumption that we for this reason need to examine the nature of facts anew. To some extent it has been taken for granted that the question of properties and particulars is the primary problem to solve, and that the question of facts is secondary. This approach naturally leads to many of the old problems of facts and complexes. By taking facts as truly basic, we should see how we can construct the particulars and universals we still have need for. In order to further this idea, I suggest that facts may be though of as tropes or once-for-all occurrent properties. However, this characterisation of facts is acceptable only if tropes manage without substances or "thin" particulars for their instantiation.

BACKGROUND: Representing is about theories and theory formation. Philosophy of science has a long-standing interest in representing. At least since Ian Hacking's modern classic Representing and Intervening analytical philosophers have struggled to combine that interest with a study of the roles of intervention studies. With few exceptions this focus of philosophy of science has been on physics and other natural sciences. In particular, there have been few attempts to analyse the use of the notion of intervention in other disciplines where intervention studies are important, such as in nursing research. One unintended consequence of this is that the relations between representing and intervening tend to be less understood outside the natural sciences. OBJECTIVES AND DESIGN: This article highlights a number of possible topics on which nursing science and analytic philosophy of science can fruitfully interact. The basic idea is simple. Building on a characterisation of interventions in terms of what is intervened on and with respect to what, we suggest that interventions in nursing research typically are a blend of varieties belonging to the three dimensions of agency, epistemology, and ontology. The details of the blend determine the relation of the particular intervention study to traditional representational categories such as inductivism and hypothetico-deductive method, and have a bearing on its explanatory power and other more theory independent features of research as well. The framework we suggest should be relevant for nurse researchers who want to adopt a more general and analytically entrenched perspective on representing and intervening than the methodological boundaries in nursing research typically allow

The hypothesis that human reasoning and decision-making can be roughly modeled by Expected Utility Theory has been at the core of decision science. Accumulating evidence has led researchers to modify the hypothesis. One of the latest additions to the field is Dual Process theory, which attempts to explain variance between participants and tasks when it comes to deviations from Expected Utility Theory. It is argued that Dual Process theories at this point cannot replace previous theories, since they, among other things, lack a firm conceptual framework, and have no means of producing independent evidence for their case.

Polygenic effects have more than one cause. They testify to the fact that several causal contributors are sometimes simultaneously involved in causation. The importance of polygenic causation was noticed early on by Mill (1893). It has since been shown to be a problem for causal-law approaches to causation and accounts of causation cast in terms of capacities. However, polygenic causation needs to be examined more thoroughly in the emerging literature on causal mechanisms. In this paper I examine whether an influential theory of mechanisms proposed by Peter Machamer, Lindley Darden and Carl Craver can accommodate polygenic effects and other forms of causal interaction. This theory is problematic, I will argue, because it ascribes a central role to activities. In it, activities are needed not only to constitute mechanisms but also to perform the causal role of mechanisms. Any such mechanism-as-activity will be incompatible with causal situations where either no or merely another kind of activity occurs. But, as I will try to illustrate in this paper, both kinds of situation may be frequent. If I am right, the view that Machamer and colleagues suggest leads to an impoverished conception of mechanism.

Researchers often aim to make correct inferences both about that which is actually studied and about what the results generalize to. The language of internal and external validity is not used by everyone, but many of us would agree that intuitively the distinction makes a lot of sense. Two claims are commonly made with respect to internal and external validity. The first is that internal validity is prior to external validity since there is nothing to generalize if the findings obtained in, for instance, the experimental setting do not hold. The first claim is explicit in many writings. See for instance Francisco Guala’s influential book The methodology of experimental economics. And it is often implicitly relied on. The second claim is that researchers have to make a trade-off between internal and external validity. When one is increased, the other will decrease. The second claim was made already from the start by D.T Campbell in his classic Factors relevant to the validity of experiments in social settings. There is a certain tension between the first and the second claim. It has been argued before that it might be difficult to combine them. We intend to make the stronger point that both claims are misconstrued. Our hypothesis is that the relationship between internal and external validity has to be re-conceptualized, and we will briefly indicate how