Philosophers disagree how abstract, theoretical principles can be applied to instances. This paper generates a puzzle for law theorists, causal theorists and inductivists alike. Intractability can force scientists to use a “semi-empirical” method, in which some of an equation's theoretically-determinable parameters are replaced with values taken directly from the data. This is not a purely deductive or inductive process, nor does it involve causes and capacities in any simple way (Humphreys 1995). I argue the predictive successes of such methods require us to reanalyze our views about the nature of prediction, the status of models, and the goal(s) of science. When laws and experimental evidence are neither individually nor jointly sufficient for prediction, models become the locus of understanding. I analyze an historically important debate about the use of semi-empirical methods to construct potential energy surfaces.

This study concerns logical systems considered as theories. By searching for the problems which the traditionally given systems may reasonably be intended to solve, we clarify the rationales for the adequacy criteria commonly applied to logical systems. From this point of view there appear to be three basic types of logical systems: those concerned with logical truth; those concerned with logical truth and with logical consequence; and those concerned with deduction per se as well as with logical truth and logical consequence. Adequacy criteria for systems of the first two types include: effectiveness, soundness, completeness, Post completeness, “strong soundness” and strong completeness. Consideration of a logical system as a theory of deduction leads us to attempt to formulate two adequacy criteria for systems of proofs. The first deals with the concept of rigor or “gaplessness” in proofs. The second is a completeness condition for a system of proofs. An historical note at the end of the paper suggests a remarkable parallel between the above hierarchy of systems and the actual historical development of this area of logic.

In trying to characterize the relationship between psychology and neuroscience, the trend has been to argue that reductionism does not work without suggesting a suitable substitute. I offer explanatory extension as a good model for elucidating the complex relationship among disciplines which are obviously connected but which do not share pragmatic explanatory features. Explanatory extension rests on the idea that one field can “illuminate” issues that were incompletely treated in another. In this paper, I explain how this “illumination” would work between psychology and neuroscience.

In two recent papers, I criticized Ronald N. Giere's and Larry Laudan's arguments for ‘naturalizing’ the philosophy of science (Siegel 1989, 1990). Both Giere and Laudan replied to my criticisms (Giere 1989, Laudan 1990b). The key issue arising in both interchanges is these naturalists' embrace of instrumental conceptions of rationality, and their concomitant rejection of non-instrumental conceptions of that key normative notion. In this reply I argue that their accounts of science's rationality as exclusively instrumental fail, and consequently that their cases for ‘normatively naturalizing’ the philosophy of science fail as well.

This paper considers the implications for the relational-substantival debate of observations of parity nonconservation in weak interactions, a much neglected topic. It is argued that ‘geometric proofs’ of absolute space, first proposed by Kant (1768), fail, but that parity violating laws allow ‘mechanical proofs’, like Newton's laws. Parity violating laws are explained and arguments analogous to those of Newton's Scholium are constructed to show that they require absolute spacetime structure—namely, an orientation—as Newtonian mechanics requires affine structure. Finally, it is considered how standard relationist responses to Newton's argument might respond to the new challenge of parity nonconservation.

1. Some Preliminary Distinctions. The relation between the natural and the social sciences, as it bears on their respective subject-matters, methods, and propositions, has long been a source of problems for the philosophy of science. The title of this paper is intended to indicate one of the most basic of these problems. Before developing my point, however, I wish to guard against a possible misinterpretation. I am not questioning the accepted fact that as knowledge in any field advances men may come to recognize the incorrectness of what they had previously regarded as “laws” in that field, and may consequently “change” these laws to take account of such increased knowledge. Let me call this kind of change of laws doctrinal change. The kind of change about which I am asking is rather a change in the subject-matter itself insofar as it is subject to laws—i.e., a change in the causal relations among the facts, objects, properties, events, or whatever they may be called, with which the science deals. Let me call this kind of change of laws factual change. Now, without inquiring more fully at the moment into the nature of scientific laws as such, we may say that the history of science shows that men can and do effect doctrinal changes in the laws of any science, natural as well as social, and formal as well as empirical. And it is recognized also, with minor exceptions to be noted later, that men cannot effect factual changes in the laws of the natural sciences, since these are independent of human volition or decision. The question I am asking, then, is whether men can effect factual changes in the laws of the social sciences.

We revive the idea that a deductive-nomological explanation of a scientific theory by its successor may be defensible, even in those common and troublesome cases where the theories concerned are mutually incompatible; and limiting, approximating and counterfactual assumptions may be required in order to define a logical relation between them. Our solution is based on a general characterization of limiting relations between physical theories using the method of nonstandard analysis.

It is proposed that the recent controversy over “time-symmetric quantum counterfactuals” (TSQCs), based on the Aharonov-Bergmann-Lebowitz Rule for measurements of pre- and post-selected systems, can be clarified by taking TSQCs to be counterfactuals with a specific type of compound antecedent. In that case, inconsistency proofs such as that of Sharp and Shanks (1993) are not applicable, and the main issue becomes not whether such statements are true, but whether they are nontrivial. The latter question is addressed and answered in the negative. Thus it is concluded that TSQCs, understood as counterfactuals with a compound antecedent, are true but only trivially so, and provide no new contingent information about specific quantum systems (except in special cases already identified in literature).

Quantum mechanics predicted the Aharonov-Bohm effect and violations of Bell inequalities before either phenomenon was experimentally verified. It is now commonly taken to explain both phenomena. Maudlin has pointed out significant disanalogies between these phenomena. But he has failed to appreciate the striking analogy that emerges when one examines the structure of their quantum mechanical explanations. The fact that each may be explained quantum mechanically in terms of a locally-acting, but nonseparable process suggests that the lesson of quantum nonlocality may be that while there is no action at a distance, the world is nonseparable.

Bogen and Woodward argued the indirect connection between data and theory in terms of their conception of “phenomena.” I outline and elaborate on their presentation. To illuminate the connection with contemporary thinking in terms of models, I distinguish between phenomena tokens, representations of which can be identified with data models, and phenomena types that can be identified with relatively low-lying models or aspects of models in the model hierarchy. Throughout I stress the role of idealization in these considerations.

There are two senses of ‘what scientists know’: An individual sense (the separate opinions of individual scientists) and a collective sense (the state of the discipline). The latter is what matters for policy and planning, but it is not something that can be directly observed or reported. A function can be defined to map individual judgments onto an aggregate judgment. I argue that such a function cannot effectively capture community opinion, especially in cases that matter to us.

This paper considers the relationship between continuum hydrodynamics and discrete molecular dynamics in the context of explaining the behavior of breaking droplets. It is argued that the idealization of a fluid as a continuum is actually essential for a full explanation of the drop breaking phenomenon and that, therefore, the less “fundamental,” emergent hydrodynamical theory plays an ineliminable role in our understanding.

Philosophers have traditionally conceived of discovery in terms of internal cognitive acts. Close consideration of Rosalind Franklin's role in the discovery of the DNA double helix, however, reveals some problems with this traditional conception. This article argues that defining discovery in terms of mental operations entails problematic conclusions and excludes acts that should fall within the domain of discovery. It proposes that discovery be expanded to include external acts of making visible. Doing so allows for a reevaluation of Franklin's role in the discovery of the structure of DNA.

The discovery of the Higgs particle required a signal of 5σ significance. The rigid application of that condition is a convention that disregards more specific aspects of the given experiment. In particular, it does not account for the characteristics of the look elsewhere effect in the individual experimental context. The paper relates this aspect of data analysis to the question as to what extent theoretical reasoning should be admitted to play a role in the assessment of the significance of empirical data.

Chemists take mechanisms to be an important way of explaining chemical change. I examine the usefulness of the mechanism approach in the recent philosophical literature in explicating the explanatory use of mechanisms by organic chemists. I argue that chemists consider a mechanism to be explanatory because it accounts for the “dynamic process of bringing about” (Tabery 2004, 10) chemical change. For chemists, mechanisms are causal explanations based on interventions that show “how some possibilities depend on others” (Woodward 2003, 375). Only possibilities are achievable because chemists face a number of challenges when they explain by means of a mechanism.

Focused correlation compares the degree of association within an evidence set to the degree of association in that evidence set given that some hypothesis is true. Wheeler and Scheines have shown that a difference in incremental confirmation of two evidence sets is robustly tracked by a difference in their focus correlation. In this essay, we generalize that tracking result by allowing for evidence having unequal relevance to the hypothesis. Our result is robust as well, and we retain conditions for bidirectional tracking between incremental confirmation measures and focused correlation.

Newton's methodology is significantly richer than the hypothetico-deductive model. It is informed by a richer ideal of empirical success that requires not just accurate prediction but also accurate measurement of parameters by the predicted phenomena. It accepts theory-mediated measurements and theoretical propositions as guides to research. All of these enrichments are exemplified in the classical response to Mercury's perihelion problem. Contrary to Kuhn, Newton's method endorses the radical transition from his theory to Einstein's. The richer themes of Newton's method are strikingly realized in a challenge to general relativity from a new problem posed by Mercury's perihelion.

In quantum field theory divergent expressions are “discarded”, leaving finite expressions which provide the best predictions anywhere in science. In fact, this “renormalization procedure” involves no mystery or illegitimate operations. This paper explains, in terms accessible to non-experts, how the procedure really works and explores some different ways in which physicists have suggested that one understand it.

On the critical side it is argued that, contrary to a widespread view, the explanation of particular facts does not play a central role in pure science and hence that philosophers of science are misguided in supposing that the understanding of such explanations is one of the central tasks of the philosophy of science. It is suggested that the view being attacked may stem in part from an impression that the establishing of a general law is tantamount to the explanation of particular facts that “fall under” the law. This suggestion effects a bridge to the more positive part of the paper, which consists of an exploration of the complexities exhibited by the relation between the two activities. More specifically, I point out a number of disabilities, any one of which could prevent us from being able to explain particular facts that fall under a given law even after having established the law. Some of these have to do with the form of the law, and some have to do with our powers of detection vis-à-vis the particular facts in question. The former sort have to do with the ways in which laws may deviate from the strict-necessary-and-sufficient-condition ideal. The latter include the following points. (1) The individual explanatory factors may lie beyond our present powers of detection. (2) The complexity of such factors may be too great for us to be able to interrelate them. (3) We may be unable to apply concepts used in the law to facts in this area (although they are in fact applicable).

We list, with discussions, various principles of scientific realism, in order to exhibit their diversity and to emphasize certain serious problems of formulation. Ontological and epistemological principles are distinguished. Within the former category, some framed in semantic terms (truth, reference) serve their purpose vis-à-vis instrumentalism (Part 1). They fail, however, to distinguish the realist from a wide variety of (constructional) empiricists. Part 2 seeks purely ontological formulations, so devised that the empiricist cannot reconstruct them from within. The main task here is to characterize “independence of mind”. A pair of notions, “physical invariance” and “anti-determination”, seem to work. They enable us to assess anew “the problem of constructing the physical out of the phenomenal” (yielding certain clarifications demanded by Goodman). Modern cosmology, especially, is seen to present insuperable obstacles to such empiricist approaches to science. The final section on epistemological principles reveals a morass better avoided in favor of an elementary claim about perception, together with a rejection of any absolute observation/theory dichotomy. Finally, a positive, realist notion of “observable-in-principle” is sketched, and it is suggested that, from the perspective of relativistic cosmology, even this defines no boundary to potential knowledge.