Johannes Persson

Semmelweis’s work predates the discovery of the power of randomization in medicine by almost a century. Although Semmelweis would not have consciously used a randomized controlled trial (RCT), some features of his material—the allocation of patients to the first and second clinics—did involve what was in fact a randomization, though this was not realised at the time. This article begins by explaining why Semmelweis’s methodology, nevertheless, did not amount to the use of a RCT. It then shows why it is descriptively and normatively interesting to compare what he did with the modern approach using RCTs. The argumentation centres on causal inferences and the contrast between Semmelweis’s causal concept and that deployed by many advocates of RCTs. It is argued that Semmelweis’s approach has implications for matters of explanation and medical practice.

Sometimes instances of perceived causation turn out to lack causal relata. The reasons may vary. Causation may display itself as prevention, or as omission, and in some cases causation occurs within such complex environments that few of the things we associate with causes and effects are true of them, etc. But even then, there may be causal explanations to be had. This suggests that the explanatory power of causal reports have other sources than the relation between cause and effect. In this paper it is argued that the causal mechanisms we allude to in explanations have relevant determinables other than the traditionally acknowledged ones. The traditional but in this aspect mistaken view of causation is to be blamed. Discernability, complexity of manifestation, originality, and even stability have often been overlooked. We know, that, in fact, heat is a constant attendant of flame; but what is the connexion between them, we have no room so much as to conjecture or imagine. (Hume 1777, VII. 2, 64).

Isaac Levi is more interested in inquiry and how it progresses than he is in metaphysics. Questions concerning the role of disposition predicates in inquiry are more central to him than those concerning the nature and reality of dispositions. It has not stopped him from giving me and others very useful metaphysical advice. Currently, where empirical metaphysics is in vogue, there is every reason to see whether the two forms of philosophical interest might interlock substantially. Levi has stimulating ideas indeed on the two forms of philosophical interest, and has recently summarized them in the slogan: “The reality of dispositions is a work in progress”. We can learn much about what kinds of dispositions are acceptable from tracing and comparing the histories of successful and less successful disposition predicates in scientific inquiry. Levi explores one route along which dispositions become real. His idea is that the introduction of dispositions facilitates covering law explanation by increasing the number of laws. The successful disposition predicate eventually becomes integrated in scientific theory, much like an ordinary theoretical term, whereas the unsuccessful does not. My impression is that Levi thinks that this is the only way a disposition can become real. To evaluate this claim, an alternative course suggested by Jon Elster is introduced. I then try to bring out the differences between Levi's and Elster's views on dispositions, partly by suggesting that they resemble two aspects of full explanations discussed by Wesley Salmon. But more about that below

The possibility of apparently negative causation has been discussed in a number of recent works on causation, but the discussion has suffered from beingscattered. In this paper, the problem of apparently negative causation and its attemptedsolutions are examined in more detail. I discuss and discard three attempts that have beensuggested in the literature. My conclusion is negative: Negative causation shows that thetraditional cause & effect view is inadequate. A more unified causal perspective is needed.

According to Jon Elster, mechanisms are frequently occurring and easily recognizable causal patterns that are triggered under generally unknown conditions or with indeterminate consequences. In the absence of laws, moreover, mechanisms provide explanations. In this paper I argue that Elster’s view has difficulties with progressing knowledge. Normally, filling in the causal picture without revising it should not threaten one’s explanation. But this seems to be Elster’s case. The critique is constructive in the sense that it is built up from a discussion of a mechanism that might explain ‘unwarranted’ risk taking in connection with swimming—a mechanism that is mirrored in the proverb: The best swimmers drown

Background Positivism is sometimes rejected for the wrong reasons. Influential textbooks on nursing research and in other disciplines tend to reinforce the misconceptions underlying these rejections. This is problematic, since it provides students of these disciplines with a poor basis for making epistemological and methodological decisions. It is particularly common for positivist views on reality and causation to be obscured. Objectives and design The first part of this discussion paper identifies and explains the misconceptions about positivism as they appear in two influential textbooks. The second part pinpoints five mistakes these misconceptions easily result in when the researcher adopts an epistemological and methodological standpoint. What is already known about the topic? There are several impeccable descriptions of positivism in nursing research literature; but a relatively large number of inaccurate or confused views of positivism appear in the nursing research literature as well. Mistakes of the kind identified in this paper have been noted before—for instance, in Shadish. What this paper adds: This paper provides a detailed analysis of two particularly common and influential misconceptions about positivism. It traces the historical roots of these misconceptions and characterizes them more carefully than many earlier attempts have done. The paper shows how and why these misconceptions affect epistemological and methodological decisions negatively, regardless of one’s interest in positivism

Arguments from explanation, i.e. arguments in which the explanatory value of a hypothesis or premise is appealed to, are common in science, and explanatory considerations are becoming more popular in metaphysics. The paper begins by arguing that explanatory arguments in science—even when these are metaphysical explanations— may fail to be explanatory in metaphysics; there is a distinction to be drawn between metaphysical explanation and explanation in metaphysics. This makes it potentially problematic to deploy arguments from explanation in, for instance, metaphysics of science. Part of this problem has its source in that the explanatory concept differs between contexts. The paper discusses a few explanatory concepts and their corresponding arguments from explanation. Towards the end of the paper, I identify two allegedly explanatory arguments in metaphysical discourse by the concluding decisions they give rise to: the rejection of X as a metaphysical fact if X does not explain anything (the argument from explanatory inability) and the rejection of X as a metaphysical fact if X can be non-metaphysically explained (the argument from the non-metaphysically explained). I ask: What kind of concept of explanation do these arguments rely upon, and is that concept suited to the metaphysical task? Two recent examples of these arguments are used as illustration. The preliminary conclusion is that several of the strengths of arguments from explanation in science seem not to be present in metaphysical contexts

Accounts of ontic explanation have often been devised so as to provide an understanding of mechanism and of causation. Ontic accounts differ quite radically in their ontologies, and one of the latest additions to this tradition proposed by Peter Machamer, Lindley Darden and Carl Craver reintroduces the concept of activity. In this paper I ask whether this influential and activity-based account of mechanisms is viable as an ontic account. I focus on polygenic scenarios—scenarios in which the causal truths depend on more than one cause. The importance of polygenic causation was noticed early on by Mill (1893). It has since been shown to be a problem for both causal-law approaches to causation (Cartwright 1983) and accounts of causation cast in terms of capacities (Dupré 1993; Glennan 1997, pp. 605-626). However, whereas mechanistic accounts seem to be attractive precisely because they promise to handle complicated causal scenarios, polygenic causation needs to be examined more thoroughly in the emerging literature on activity-based mechanisms. The activity-based account proposed in Machamer et al. (2000, pp. 1-25) is problematic as an ontic account, I will argue. It seems necessary to ask, of any ontic account, how well it performs in causal situations where—at the explanandum level of mechanism—no activity occurs. In addition, it should be asked how well the activity-based account performs in situations where there are too few activities around to match the polygenic causal origin of the explanandum. The first situation presents an explanandum-problem and the second situation presents an explanans-problem—I will argue—both of which threaten activity-based frameworks.

We are good at discussing law statements of different epistemic status, and to describe logical relationships between different law statements. But contemporary discussion often suffers from a difficulty to formulate questions concerning laws of different ontological status. This paper presents a framework for distinguishing between properties and fake properties that seems to provide better tools for such inquiries. This paper also examines criteria for properties in connection with laws of nature. It discusses three suggested tests for properties, by Maxwell, Ramsey, and Cartwright. None of these tests is good as it stands. Rather than favouring one particular test, we should opt for methodologically stable decisions, i.e. decisions where several tests come to the same conclusion.

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?