Study of the multiplicity of interactions between invertebrate hosts and their parasites helps to define the aspects of the host immune systems that have ecological and evolutionary significance. Such study, however, reveals how much is yet unknown. For instance, the costs of mounting an immune response, the nature of the long-lasting protection sometimes attained, and the high degree of specificity observed in certain hosts are phenomena that still await full explanation. An additional puzzle is the high degree of specificity achieved (...) in light of the apparent low degree of specificity in the recognition and effector mechanisms of insect immune systems. Furthermore, while protective immunity is typically associated with vertebrate adaptive immune systems, invertebrates may have analogous capacities, whose nature is still largely unknown. This review will illustrate how the traditional host-centred view of immune defence can be usefully extended by taking account of parasite immune evasion strategies and the variation that such strategies create in the observed outcomes of infection. BioEssays 27:1026–1034, 2005. © 2005 Wiley Peiodicals, Inc. (shrink)

The ethics review of qualitative health research poses various challenges that are due to a mismatch between the current practice of ethics review and the nature of qualitative methodology. The process of obtaining ethics approval for a study by a research ethics committee before the start of a research study has been described as “procedural ethics” and the identification and handling of ethical issues by researchers during the research process as “ethics in practice.” While some authors dispute and other authors (...) defend the use of procedural ethics in relation to qualitative health research, there is general agreement that it needs to be supplemented with ethics in practice. This article aims to provide an illustration of research ethics in practice by reflecting on the ways in which we identified and addressed ethical and methodological issues that arose in the context of an interview study with mental health service users and relatives. We describe the challenges we faced and the solutions we found in relation to the potential vulnerability of research participants, the voluntariness of consent, the increase of participant access and the heterogeneity of the sample, the protection of privacy and internal confidentiality, and the consideration of personal and contextual factors. (shrink)

Editor James Fetzer presents an analytical and historical introduction and a comprehensive bibliography together with selections of many of Carl G. Hempel's most important studies to give students and scholars an ideal opportunity to appreciate the enduring contributions of one of the most influential philosophers of science of the 20th century.

Crutchfield and Redinger (2024) propose that the use of a chemical restraint that affects only a particular conscious state is ethically permissible if, and only if, (1) it is the least restrictive...

Treatment pressures are communicative strategies that mental health professionals use to influence the decision-making of mental health service users and improve their adherence to recommended treatment. Szmukler and Appelbaum describe a spectrum of treatment pressures, which encompasses persuasion, interpersonal leverage, offers and threats, arguing that only a particular type of threat amounts to informal coercion. We contend that this account of informal coercion is insufficiently sensitive to context and fails to recognize the fundamental power imbalance in mental healthcare. Based on (...) a set of counterexamples, we argue that what makes a proposal coercive is not whether service users will actually be made worse off if they reject the proposal, but rather whether they have the justified belief that this is the case. Whether this belief is justified depends on the presence of certain contextual factors, such as strong dependency on professionals and the salient possibility of formal coercion. (shrink)

Hempel seems to hold the following three views: (H1) Understanding is pragmatic/relativistic: Whether one understands why X happened in terms of Explanation E depends on one's beliefs and cognitive abilities; (H2) Whether a scientific explanation is good, just like whether a mathematical proof is good, is a nonpragmatic and objective issue independent of the beliefs or cognitive abilities of individuals; (H3) The goal of scientific explanation is understanding: A good scientific explanation is the one that provides understanding. Apparently, H1, (...) H2, and H3 cannot be all true. Some philosophers think that Hempel is inconsistent, while some others claim that Hempel does not actually hold H3. I argue that Hempel does hold H3 and that he can consistently hold all of H1, H2, and H3 if he endorses what I call the “understanding argument.” I also show how attributing the understanding argument to Hempel can make more sense of his D-N model and his philosophical analysis of the pragmatic aspects of scientific explanation. (shrink)

This paper situates Carl Hempel's 1942 paper "The Function of General Laws in History" within a broader debate over the philosophy of history in American academia between 1935 and 1943. I argue that Hempel's paper was directed against German neo-Kantianism, and show how the German debate over historiography continued between 1939 and 1943 in the context of New York through the contributions of German philosophers who operated in the same intellectual network as Hempel, namely Paul Oskar Kristeller (...) and Edgar Zilsel. Whereas this debate still witnessed many different philosophical approaches, Hempel's logico-analytic methodology would come to dominate analytic philosophy of history. (shrink)

Hempel and Oppenheim, in their paper 'The Logic of Explanation', have offered an analysis of the notion of scientific explanation. The present paper advances considerations in the light of which their analysis seems inadequate. In particular, several theorems are proved with roughly the following content: between almost any theory and almost any singular sentence, certain relations of explainability hold.

According to Hempel's paradox, evidence (E) that an object is a nonblack nonraven confirms the hypothesis (H) that every raven is black. According to the standard Bayesian solution, E does confirm H but only to a minute degree. This solution relies on the almost never explicitly defended assumption that the probability of H should not be affected by evidence that an object is nonblack. I argue that this assumption is implausible, and I propose a way out for Bayesians. Introduction (...) Hempel's paradox, the standard Bayesian solution, and the disputed assumption Attempts to defend the disputed assumption Attempts to refute the disputed assumption A way out for Bayesians Conclusion. (shrink)

Recently, Michael Friedman has claimed that virtually all the seeds of Hempel’s philosophical development trace back to his early encounter with the Vienna Circle (Friedman 2003, 94). As opposed, however, to Friedman’s view of the principal early influences on Hempel, we shall see that those formative influences originated rather with the Berlin Group. Hempel, it is true, spent the fall term of 1929 as a student at the University of Vienna, and, thanks to a letter of recommendation (...) from Hans Reichenbach, he even attended some sessions of the Vienna Circle. But he spent much less time in Vienna than in Berlin, where he studied under Reichenbach from 1926 till 1933 and wrote a dissertation on probability, Reichenbach’s specialty. Hempel also attended seminars conducted by Walter Dubislav, another member of the Berlin Group. (shrink)

According to the so-called Hempel’s Dilemma, the thesis of physicalism is either false or empty. Our intention in this paper is not to propose a solution to the Dilemma, but rather to argue as follows: to the extent that Hempel’s Dilemma applies to physicalism it equally applies to any theory that gives a deep-structure and changeable account of our experience or of high-level theories. In particular, we will show that it also applies to mind-body dualistic theories. The scope (...) of Hempel’s Dilemma turns out to be very wide: it is a special case of a general sceptical argument against changeable deep-structure theories in and outside science. (shrink)

I argue that Carl Hempel’s pioneering work on scientific explanation introduced an assumption that Hempel never motivated, namely, that explanation is an aim of science. Ever since, it has remained largely unquestioned in analytic philosophy of science. By expanding the historical scope of the debate on explanation to philosophers from the first half of the twentieth century, I show that the debate should include a critical reflection on Hempel’s assumption. This reflection includes two problems: how to motivate (...) one’s position on the aims of scientific knowledge and how to decide which examples count as expressions of those aims. (shrink)

The problem of ceteris paribus clauses and Hempel’s problem of provisos are closely-related difficulties. Both challenge advocates of accounts of scientific theories involving laws understood as universal generalizations, and they have been treated as identical problems. Earman and Roberts argue that the problems are distinct. Towards arguing against them, I characterize the relationship between Hempel’s provisos and one way of expressing ceteris paribus clauses. I then describe the relationship between the problems attributed to the clauses, suggesting that they (...) form a single problem-cluster. However, Hempel’s way of formulating provisos and discussing what they involve entangles provisos with the problem of skepticism. This creates a departure in Hempel’s discussion of provisos from the distinctive problem of vacuity which characterizes the problem of ceteris paribus clauses, though for different reasons than Earman and Roberts suggest. (shrink)

Hempel's paradox of the ravens has to do with the question of what constitutes confirmation from a logical point of view; Wason 's selection task has been used extensively to investigate how people go about attempting to confirm or disconfirm conditional claims. This paper presents an argument that the paradox is resolved, and that people's typical performance in the selection task can be explained, by consideration of what constitutes an effective strategy for seeking evidence of the tenability of universal (...) or conditional claims in everyday life. (shrink)

This paper presents a new analysis of C.G. Hempel’s conditions of adequacy for any relation of confirmation [Hempel C. G. (1945). Aspects of scientific explanation and other essays in the philosophy of science. New York: The Free Press, pp. 3–51.], differing from the one Carnap gave in §87 of his [1962. Logical foundations of probability (2nd ed.). Chicago: University of Chicago Press.]. Hempel, it is argued, felt the need for two concepts of confirmation: one aiming at true (...) hypotheses and another aiming at informative hypotheses. However, he also realized that these two concepts are conflicting, and he gave up the concept of confirmation aiming at informative hypotheses. I then show that one can have Hempel’s cake and eat it too. There is a logic that takes into account both of these two conflicting aspects. According to this logic, a sentence H is an acceptable hypothesis for evidence E if and only if H is both sufficiently plausible given E and sufficiently informative about E. Finally, the logic sheds new light on Carnap’s analysis. (shrink)

In his introductory textbook, Philosophy of natural science, Hempel presents, as an illustration and a starting point for an analysis of the processes of inventing and testing scientific theories, an account of the researches of Semmelweis the Hungarian physician who, in the middle of the xixth century, discovered the cause of puerperal fever and an effective method of prevention. The account does not involve anything that is factually untrue, but it is quite succinct, leaving out many important aspects of (...) the case. Our thesis is that, although those omissions are justified in view of the aims of the account, they are also convenient to Hempel, because they help to propagate an image of science which goes much beyond the processes of invention and test. It is an image which reflects the positivist conception of science, and thus, whatever the intentions of the author, contributes to the dissemination and strengthening of that conception, but which, at least in this case, does not correspond to reality. To demonstrate the thesis, we give an account of the parts of Semmelweis's story omitted by Hempel, and we show how they do not fit in with the positivist image of science. Along the way, we distinguish three types of critique of positivist historiography: the Kuhnian, the post-modern, and the engagé. In the conclusion, we present some considerations concerning the medical research of today. -/- . (shrink)

Hempel's Dilemma is the claim that physicalism is an ill-formed thesis because it can offer no account of the physics that it refers to: current physics will be discarded in the future, and we don't yet know the nature of future physics. This article confronts the first horn of the dilemma, and argues that our knowledge of current physics is sufficient for offering a physicalist ontology of the mind. We have good scientific evidence that future physics will be irrelevant (...) to the mind-body problem because mental processes lie safely within the well-understood domains of applicability of current physical theories. (shrink)

In his paper, "Explanations of Irrelevance" (1983), Paul Horwich proposes an amended version of hypothetico-deductivism, (H-D * ). In this discussion note it is shown that (H-D * ) has the consequence that "A is a non-black raven" confirms "All ravens are black" relative to any tautology! It is noted that Horwich's (H-D * ) bears a strong resemblance to Hempel's prediction criterion of confirmation and that the prediction criterion faces the same obstacle. A related problem for hypothetico-deductivism in (...) its simplest form--that is, E confirms H iff E is an (observational) consequence of H--is displayed. The discussion concludes with a suggestion about how (H-D * ) and simple hypothetico-deductivism might be amended in order to avoid these results. (shrink)

It is widely thought that Bayesian confirmation theory has provided a solution to Hempel's Paradox (the Ravens Paradox). I discuss one well‐known example of this approach, by John Mackie, and argue that it is unconvincing. I then suggest an alternative solution, which shows that the Bayesian approach is altogether mistaken. Nicod's Condition should be rejected because a generalisation is not confirmed by any of its instances if it is not law‐like. And even law‐like non‐basic empirical generalisations, which are expressions (...) of assumed underlying causal regularities, are not so confirmed if they are absurd in the light of our causal background knowledge or if their instances are not also possible instances of the relevant causal claim. (shrink)

The question of whether all living things are really just complex physical ones, or whether instead there are biological entities or characteristics that cannot be fully characterized in physical terms, has historical roots buried centuries deep. Carl Hempel considers this question as an empirical one for modern science to address. Hempel’s concern is not with the answer to the question, but rather with the methods by which it may be evaluated. He considers the position of those he calls (...) “mechanists,” that all living things and their biological characteristics are nothing more than complex physical systems, as equivalent to the view that in some significant sense all accurate biological theories are implied by physical ones. In so doing, Hempel seeks to draw conclusions regarding the unity of science more broadly. This paper argues that Hempel’s account, though perhaps succeeding in a crucial first step, fails on numerous points afterwards. Using the morals that may be draw from these failures, I suggest rough outlines of some alternative accounts of intertheoretic reduction. (shrink)

Preface. Almost fifty years ago, in 1948, when I was an undergraduate at Queens College in New York and a student of Carl G. Hempel's, I received from his hands an offprint of his now-classic but then just-published paper “Studies in the Logic of Explanation”, written in collaboration with Paul Oppenheim and then just published in Philosophy of Science.1 This paper greatly impressed me—and I was not alone. We have here one of those unusual publications that sets the agenda (...) for a whole generation of investigators. It set in train an enormous body of discussions and publications which shaped the course of deliberations about scientific explanation over the next decades—an effort to which my own work also made some contributions. However my present aim is not to consider what came out of the Hempel-Oppenheim paper but what went into it. I want, in sum, to consider the prehistory of that era of scientific explanation studies—and to look more closely at the background ramifications of this paper that launched a thousand others. (shrink)

Carl Hempel has proposed the following model for explanations by reasons. A was in a situation of type C. A was a rational agent at the time. In a situation of type C, any rational agent will do X. Therefore, A did X.According to Hempel overcomes the shortcomings of alternative accounts of explaining by reasons such as William Dray's model, in that the so-called evaluative principle is replaced by an empirical law. It is William Dray's contention that to (...) understand the action of a rational agent is to see that his action was appropriate in his situation. Following Dray this then means that in explaining such an action one makes use of a normative ‘principle of action', not an empirical law, which has the form ‘when in a situation of type C1… Cn the thing to do is X'. (shrink)

The adverse reaction to Hempel's 'ravens paradox' embodied in giving it that description is compared with the usual reaction of experimental subjects to the Wason selection task.

Functional explanations are regarded as a special type of explanation by many biologists. Philosophers of science tend to agree that they are weak forms of the common modes of explanation, although the elucidation of the logical structure involved is difficult. The present paper shows that Hempel's reconstruction of functional explanations is inadequate on pragmatic grounds. Thus his conclusion that such explanations are necessarily weak is also objectionable. There is no reason for allotting functional explanations a special logical status.

SummaryHempel's Deductive‐Nomological model of explanation is compared to Sellars' brand of essentialism. The source of their differences is shown to lie in their views on the explanatory role of inductively based generalizations. An adequate explanation requires a reasoned account of why an empirical generalization fails. On Sellars' view this entails concentrating on the nature of the things whose behavior is in question. We thereby remove ourselves from the misleading positivist methodology in which one counterinstance renders a generalization uninteresting. It is (...) suggested instead that “disconfirmed” generalizations are of crucial positive methodological importance for purposes of theory development.RésuméLe modèle déductif‐nomologique de Hempel est comparéà l'essentialisme dans la version qu'en propose Sellars. L'auteur montre que leurs différences proviennent de ce qu'ils jugent différemment le rôle explicatif des généralisations inductives et les raisons de l'échec d'une généralisation empirique. D'après Sellars, il faut par conséquent se concentrer sur la nature des choses dont on observe le comportement; on évite ainsi les problèmes méthodologiques soulevés par les théories positivistes standard de la confirmation. L'auteur conclut en montrant que des généralisations infirmées ont une importance positive capitale pour le développement des théories. (shrink)

To solve the highly counterintuitive paradox of confirmation represented by the statement, “A pair of red shoes confirms that all ravens are black,” Hempel employed a strategy that retained the equivalence condition but abandoned Nicod’s irrelevance condition. However, his use of the equivalence condition is fairly ad hoc, raising doubts about its applicability to this problem. Furthermore, applying the irrelevance condition from Nicod’s criterion does not necessarily lead to paradoxes, nor does discarding it prevent the emergence of paradoxes. (...) class='Hi'>Hempel’s approach fails to adequately resolve the paradox. (shrink)

The paper takes a novel approach to a classic problem—Hempel’s Raven Paradox. A standard approach to it supposes the solution to consist in bringing our inductive logic into “reflective equilibrium” with our intuitive judgements about which inductive inferences we should license. This approach leaves the intuitions as a kind of black box and takes it on faith that, whatever the structure of the intuitions inside that box might be, it is one for which we can construct an isomorphic formal (...) edifice, a system of inductive logic. By popping open the box we can see whether that faith is misplaced. I aim, therefore, to characterize our pre-theoretical, intuitive understanding of generalizations like “ravens are black” and argue that, intuitively, we take them to mean, for instance: “ravens are black by some indeterminate yet characteristic means.” I motivate and explicate this formulation and bring it to bear on Hempel’s Problem. (shrink)

This paper makes the case for the relevance of C. G. Hempel’s 1942 proposal of the usage of «covering laws» in History. To do so, it argues that such a proposal reflects how 18 and 19th centuries «philosophy of History» became methods or epistemology of History. This carried a change in meaning of «History»: no longer a succession of past events but the study of documented human action (including of scientific kind in general), its distinction vis-à-vis philosophy, sociology etc., (...) becomes a minor matter as far as logic of research is concerned. Also present in this paper is the conception of theory as a conceptual mode of narrative, and the defense of a development of theories alongside their practice, not apart from them. Authors considered besides Hempel range from Max Weber to Sigmund Freud, from Arthur C. Danto to Albert O. Hirschmann. (shrink)

Carl G. Hempel has often stated that inductive-statistical explanations, as he conceives them, are inductive arguments. This discussion note raises the question of whether such arguments are to be understood as (1) arguments of the traditional sort, containing premises and conclusions, governed by some sort of inductive "acceptance rules," or (2) something more closely akin to Carnap's degree of confirmation statements which occur in an inductive logic which entirely eschews inductive "acceptance rules." Hempel's writings do not seem unequivocal (...) on this issue. It is suggested that adoption of construal (2) would remove the need for Hempel's high probability requirement on I-S explanations. (shrink)

Hempel’s account of thought experiments has been discussed only by a very few authors and, for the most part, with rather cursory remarks. Its importance, however, is not only historical, but also systematic theoretical, because it involves the distinction between discovery and justification, a main pillar of neopositivistic philosophy of science. Hempel raised the question whether thought experiments constitute a methodological component of scientific research or, on the contrary, are merely a heuristic-psychological device for obtaining and/or transmitting new (...) ideas. While conceding a few exceptions in the natural sciences, he argued that thought experiments always have a heuristic character in the social sciences. There is however a fundamental tension in Hempel’s conception of thought experiments, between the thesis of methodological monism and the neopositivistic dichotomy discovery/justification. On the one hand, on the basis of the unity of scientific method, Hempel admits a difference only in degree between the natural and the human sciences, but on the other hand, he draws a principled distinction between thought experiments of the human sciences (which have only a greater or lesser heuristic value) and those of the natural sciences (which may have also a cognitive-justificatory value). If one assumes the unity of method in the minimal sense in which no scientific knowledge can renounce intersubjective controllability, this tension can be removed either by rejecting the discovery/justification dichotomy or by interpreting it differently. Here, following the second path, two senses of the dichotomy are distinguished, one of which must be accepted, while the other rejected. This removes the internal tension in Hempel’s conception of thought experiments and suggests the thesis that any plausible thought experiment, both in the natural and the human sciences, must already contain some justification, implicit or explicit, of the theoretical hypotheses that they formulate. (shrink)