The works of Carl Gustav Hempel

The works of Carl Gustav Hempel     

Natural laws and the problem of provisos

Hempel and Giere contend that the existence of provisos poses grave difficulties for any regularity account of physical law. However, Hempel and Giere rely upon a mistaken conception of the way in which statements acquire their content. By correcting this mistake, I remove the problem Hempel and Giere identify but reveal a different problem that provisos pose for a regularity account — indeed, for any account of physical law according to which the state of affairs described by a law-statement presupposes a Humean regularity. These considerations suggest a normative analysis of law-statements. On this view, law-statements are not distinguished from accidental generalizations by the kind of Humean regularities they describe because a law-statement need not describe any Humean regularity. Rather, a law-statement says that in certain contexts, one ought to regard the assertion of a given type of claim, if made with justification, as a proper way to justify a claim of a certain other kind.     

Hempel’s logic of confirmation

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.     

On empirical interpretation

The view that scientific theories are partially interpreted deductive systems (theoretical deductivism) is defended against recent criticisms by Hempel. Hempel argues that the reliance of theoretical inferences (both from observation to theory and also from theory to theory) uponceteris paribus conditions orprovisos must prevent theories from establishing deductive connections among observations. In reply I argue, first, that theoretical deductivism does not in fact require the establishing of such deductive connections: I offer alternative H-D analyses of these inferences. Second, I argue that when the refined character of scientific observation is taken into account, we find that a theorymay after all establish such deductive connections among scientific observations, without reliance on provisos.These conclusions are based on the multi-level Popperian contextualist account of empirical interpretation sketched in a previous paper. As before, I claim that the supposed objections to theoretical deductivism depend upon questionable empiricist theses unnecessarily conjoined with theoretical deductivism by the Logical Positivists. Theoretical deductivism itself is unaffected by these arguments, and remains (when empirical interpretation is properly analyzed) the best account of scientific theories.This paper develops points first made very briefly in my forthcoming review (c). I would like to thank Professor Hempel for correspondence regarding an earlier version of that review, and Professor Demopoulos for commissioning the review.     

<Emphasis Type="Italic">Wissenschaftslogik</Emphasis>: The role of logic in the philosophy of science

Carl Hempel introduced what he called “Craig’s theorem” into the philosophy of science in a famous discussion of the “problem of theoretical terms.” Beginning with Hempel’s use of ‘Craig’s theorem,” I shall bring out some of the key differences between Hempel’s treatment of the “problem of theoretical terms” and Carnap’s in order to illuminate the peculiar function of Wissenschaftslogik in Carnap’s mature philosophy. Carnap’s treatment, in particular, is fundamentally anti-metaphysical—he aims to use the tools of mathematical logic to dissolve rather solve traditional philosophical problems—and it is precisely this point that is missed by his logically-minded contemporaries such as Hempel and Quine.     

Grünbaum's ‘defense’ of the symmetry thesis

The purpose of this paper is to demonstrate that Grünbaum's purported defense of Hempel's thesis of the symmetry of explanation and prediction is fundamentally inadequate by virtue of the fact that Grünbaum adopts an extended and revised version of the thesis pertaining to scientific understanding in general in lieu of the original and restricted version advanced by Hempel pertaining to scientific explanation in particular. When Hempel's thesis rather than Grünbaum's revision is recognized as the relevant object of criticism, it becomes clear that Grünbaum has not demonstrated that Hempel ab omni naevo vindicates. Indeed, when correctly understood, it becomes clear that Bromberger's criticisms, especially, support the sound conclusion that the relationship between explanations and predictions is sometimes symmetrical yet sometimes asymmetrical, i.e., the relationship that obtains is non-symmetrical.     

Nancey Murphy's Work

Nancey Murphy has been influential in the religion-and-science field through her espousal of the work of Imre Lakatos, more recently developed into a three-tier approach to the joint epistemology of scientific and religious thought incorporating also the ideas of Hempel and MacIntyre. She has proposed a substantial influence of the radical reformed tradition on science and has demonstrated the nature of social influences on the form of Darwinism. She has developed important links between ethics and the science-theology debate and has examined in depth ideas associated with hierarchical structuring, supervenience, and the nature of the soul. Together these form a unique and sharply focused contribution to the understanding of the relation between science and religion.     

Grounding and the explanatory role of generalizations

According to Hempel’s (Aspects of scientific explanation and other essays. The Free Press, New York, 1965) influential theory of explanation, explaining why some a is G consists in showing that the truth that a is G follows from a law-like generalization to the effect that all Fs are G together with the initial condition that a is F. While Hempel’s overall account is now widely considered to be deeply flawed, the idea that some generalizations play the explanatory role that the account predicts is still often endorsed by contemporary philosophers of science. This idea, however, conflicts with widely shared views in metaphysics according to which the generalization that all Fs are G is partially explained by the fact that a is G. I discuss two solutions to this conflict that have been proposed recently, argue that they are unsatisfactory, and offer an alternative.     

Grounding, scientific explanation, and Humean laws

It has often been argued that Humean accounts of natural law cannot account for the role played by laws in scientific explanations. Loewer (Philosophical Studies 2012) has offered a new reply to this argument on behalf of Humean accounts—a reply that distinguishes between grounding (which Loewer portrays as underwriting a kind of metaphysical explanation) and scientific explanation. I will argue that Loewer’s reply fails because it cannot accommodate the relation between metaphysical and scientific explanation. This relation also resolves a puzzle about scientific explanation that Hempel and Oppenheim (Philosophy of Science 15:135–75, 1948) encountered.     

Statistical relevance and explanatory classification

Numerous philosophers, among them Carl G. Hempel and Wesley C. Salmon, have attempted to explicate the notion of explanatory relevance in terms of the statistical relevance of various properties of an individual to the explanandum property itself (or what is here called narrow statistical relevance). This approach seems plausible if one assumes that to explain an occurrence is to show that it was to be expected or to exhibit its degree of expectability and the factors which influence its expectability. But considerations of narrow statistical relevance do not provide an adequate basis for explanatory classification, and the aforementioned views of explanation are accordingly mistaken. Explanatory classification must provide at least a partial account of the nature of a thing, and such an account will generally go beyond what is required as a basis for correct expectation.     

Why Bayesians Needn’t Be Afraid of Observing Many Non-black Non-ravens

According to Hempel??s raven paradox, the observation of one non-black non-raven confirms the hypothesis that all ravens are black. Bayesians such as Howson and Urbach (Scientific reasoning: the Bayesian approach, 2nd edn. Open Court, Chicago, 1993) claim that the raven paradox can be solved by spelling out the concept of confirmation in the sense of the relevance criterion. Siebel (J Gen Philos Sci 35:313?C329, 2004) disputes the adequacy of this Bayesian solution. He claims that spelling out the concept of confirmation in the relevance sense lets the raven paradox reappear as soon as numerous non-black non-ravens are observed. It is shown in this paper that Siebel??s objection to the Bayesian solution is flawed. Nevertheless, the objection made by Siebel may give us an idea of how Bayesians can successfully handle situations in which we observe more than one non-black non-raven.     

The Logic of Theory Assessment

This paper starts by indicating the analysis of Hempel’s conditions of adequacy for any relation of confirmation (Hempel, 1945) as presented in Huber (submitted). There I argue contra Carnap (1962, Section 87) that Hempel felt the need for two concepts of confirmation: one aiming at plausible theories and another aiming at informative theories. However, he also realized that these two concepts are conflicting, and he gave up the concept of confirmation aiming at informative theories. The main part of the paper consists in working out the claim that one can have Hempel’s cake and eat it too — in the sense that there is a logic of theory assessment that takes into account both of the two conflicting aspects of plausibility and informativeness. According to the semantics of this logic, α is an acceptable theory for evidence β if and only if α is both sufficiently plausible given β and sufficiently informative about β. This is spelt out in terms of ranking functions (Spohn, 1988) and shown to represent the syntactically specified notion of an assessment relation. The paper then compares these acceptability relations to explanatory and confirmatory consequence relations (Flach, 2000) as well as to nonmonotonic consequence relations (Kraus et al., 1990). It concludes by relating the plausibility-informativeness approach to Carnap’s positive relevance account, thereby shedding new light on Carnap’s analysis as well as solving another problem of confirmation theory. A precursor of this paper has appeared as “The Logic of Confirmation and Theory Assessment” in L. Běhounek & M. Bílková (eds.), The Logica Yearbook 2004, Prague: Filosofia, 2005, 161–176.     

The Berlin School of Logical Empiricism and its Legacy

What has become generally known as the Berlin School of Logical Empiricism constitutes a philosophical movement that was erected on foundations laid by Albert Einstein. His revolutionary work in physics had a profound impact on philosophers interested in scientific issues, prominent among them Paul Oppenheim and Hans Reichenbach, the founding fathers of the school, who joined in viewing him as their hero among philosopher–scientists. Overall the membership of this school falls into three groups. The founding generation was linked by the circumstance that both Grelling and Reichenbach were collaborators of Oppenheim; the middle generation by the fact that both Hempel and Helmer were students of Reichenbach’s in Berlin; and the younger generation by the fact that all of its members were students and (at least in their early years) disciples either of Reichenbach’s or of Hempel’s in the USA. Three stages are at issue: an initial phase in Berlin, a transatlantic migration, and a continuation in the U.S.A.—principally in Pittsburgh.     

Justifying inference to the best explanation as a practical meta-syllogism on dialectical structures

This article discusses how inference to the best explanation (IBE) can be justified as a practical meta-argument. It is, firstly, justified as a practical argument insofar as accepting the best explanation as true can be shown to further a specific aim. And because this aim is a discursive one which proponents can rationally pursue in—and relative to—a complex controversy, namely maximising the robustness of one’s position, IBE can be conceived, secondly, as a meta-argument. My analysis thus bears a certain analogy to Sellars’ well-known justification of inductive reasoning (Sellars, In: Essays in honour of Carl G. Hempel, 1969); it is based on recently developed theories of complex argumentation (Betz, In: Theorie dialektischer Strukturen, 2010a).     

Assessing theories,Bayes style

The problem addressed in this paper is “the main epistemic problem concerning science”, viz. “the explication of how we compare and evaluate theories [...] in the light of the available evidence” (van Fraassen, BC, 1983, Theory comparison and relevant Evidence. In J. Earman (Ed.), Testing scientific theories (pp. 27–42). Minneapolis: University of Minnesota Press). Sections 1– 3 contain the general plausibility-informativeness theory of theory assessment. In a nutshell, the message is (1) that there are two values a theory should exhibit: truth and informativeness—measured respectively by a truth indicator and a strength indicator; (2) that these two values are conflicting in the sense that the former is a decreasing and the latter an increasing function of the logical strength of the theory to be assessed; and (3) that in assessing a given theory by the available data one should weigh between these two conflicting aspects in such a way that any surplus in informativeness succeeds, if the shortfall in plausibility is small enough. Particular accounts of this general theory arise by inserting particular strength indicators and truth indicators. In Section 4 the theory is spelt out for the Bayesian paradigm of subjective probabilities. It is then compared to incremental Bayesian confirmation theory. Section 4 closes by asking whether it is likely to be lovely. Section 5 discusses a few problems of confirmation theory in the light of the present approach. In particular, it is briefly indicated how the present account gives rise to a new analysis of Hempel’s conditions of adequacy for any relation of confirmation (Hempel, CG, 1945, Studies in the logic of comfirmation. Mind, 54, 1–26, 97–121.), differing from the one Carnap gave in § 87 of his Logical foundations of probability (1962, Chicago: University of Chicago Press). Section 6 adresses the question of justification any theory of theory assessment has to face: why should one stick to theories given high assessment values rather than to any other theories? The answer given by the Bayesian version of the account presented in section 4 is that one should accept theories given high assessment values, because, in the medium run, theory assessment almost surely takes one to the most informative among all true theories when presented separating data. The concluding section 7 continues the comparison between the present account and incremental Bayesian confirmation theory.     

亨佩尔确证悖论及其解决方案探析

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. Hempel’s approach fails to adequately resolve the paradox. __________ Translated from Ziran Bianzhengfa Yanjiu 自然辩证法研究 (Studies in Dialectics of Nature), 2005, (8): 33–37     

Causation and the flow of energy

Causation has traditionally been analyzed either as a relation of nomic dependence or as a relation of counterfactual dependence. I argue for a third program, a physicalistic reduction of the causal relation to one of energy-momentum transference in the technical sense of physics. This physicalistic analysis is argued to have the virtues of easily handling the standard counterexamples to the nomic and counterfactual analyses, offering a plausible epistemology for our knowledge of causes, and elucidating the nature of the relation between causation and physical science.The development of this paper owes a great deal to the critical acumen of my colleagues. I want to thank especially Adam Morton, Ernest Loevinsohn, and Jon Levinson. I owe a debt of gratitude to Professor Carl G. Hempel for kindly commenting on a draft of this paper which led to numerous improvements. But most especially of all I want to thank David Lewis, whose indefatigable insistence on philosophical clarity saved this paper from many turbidities and falsehoods manifest in earlier drafts. I also wish to thank my students, Mark Folsom and Ken Waters, for spotting a serious inaccuracy.     

Aspects of the logic of history-of-science explanation

The topic of history-of-science explanation is first briefly introduced as a generally important one for the light it may shed on action theory, on the logic of discovery, and on philosophy's relations with historiography of science, intellectual history, and the sociology of knowledge. Then some problems and some conclusions are formulated by reference to some recent relevant literature: a critical analysis of Laudan's views on the role of normative evaluations in rational explanations occasions the result that one must make aconceptual distinction between evaluations and explanations of belief, and that there are at leastthree subclasses of the latter, rational, critical, and theoretical; I then discuss the problem of whether explanations of discoveries are self-evidencing and predictive by focusing on views of Hempel and Nickles, and I attempt a formalization of some aspects of the problem. Finally, a more systematic and concrete analysis is undertaken by using as an example the explanation of Galileo's rejection of space-proportionality, and it is argued that the historical explanation of scientific beliefs is a type of logical analysis.     

The neuromotor examination of the preschool child and its prognostic significance

The present paper reviews the methods available for neurological or neuromotor evaluation at preschool age. General textbooks on pediatric neurology describe the neurological examination at preschool age in terms of the assessment of the evaluation of cranial nerves, muscle tone, muscle power, reflexes, and the presence of abnormal movements. They stress the fact that assessment at preschool age is difficult because of the time needed to achieve the child's cooperation. Noncooperation at the preschool neurological exam is associated with an increased risk for learning and behavioral problems at school age. At present three age-specific and standardized test for neurological or neuromotor evaluation at preschool age are available. The method of Amiel-Tison and Gosselin, of which information can be accessed easily, has the drawback that it focuses on muscle tone and reflexes. It pays little attention to the quality of spontaneous motor behavior. The other two methods, i.e., the neuromotor behavioral inventory (NBI) and the Hempel assessment, are probably more promising in terms of assessment of minor neurological dysfunction as these methods pay ample attention to the child's quality of motor behavior. All methods have in common that information in terms of concurrent validity is scarce, with no information on predictive validity. This means that further research on applicability and validity of preschool neuromotor assessment is urgently needed.