In this paper, I argue that unification is neither necessary nor sufficient for explanation. Focusing on the versions of the unificationist theory of explanation of Kitcher and of Schurz and Lambert, I establish three theses. First, Kitcher's criterion of unification is vitiated by the fact that it entails that every proposition can be explained by itself, a flaw that it is unable to overcome. Second, because neither Kitcher's theory nor that of Schurz and Lambert can solve the problems of asymmetry and accidental generalizations, it follows that unification is not sufficient to ground explanation. Third, some good explanations are disunifying, which entails that unification is not necessary for explanation either.

Inquiries into the nature of scientific modeling have tended to focus their attention on mathematical models and, relatedly, to think of nonconcrete models as mathematical structures. The arguments of this article are arguments for rethinking both tendencies. Nonmathematical models play an important role in the sciences, and our account of scientific modeling must accommodate that fact. One key to making such accommodations, moreover, is to recognize that one kind of thing we use the term ‘model’ to refer to is a collection of propositions.

Biological processes are often explained by identifying the underlying mechanisms that generate a phenomenon of interest. I characterize a basic account of mechanistic explanation and then present three challenges to this account, illustrated with examples from molecular biology. The basic mechanistic account (1) is insufficient for explaining nonsequential and nonlinear dynamic processes, (2) is insufficient for explaining the inherently stochastic nature of many biological mechanisms, and (3) fails to give a proper framework for analyzing organization. I suggest that biological processes are best approached as a multidimensional gradient—with some processes being paradigmatic cases of mechanisms and some being marginal cases.

I identify the special sort of stability (invariance, resilience, etc.) that distinguishes laws from accidental truths. Although an accident can have a certain invariance under counterfactual suppositions, there is no continuum between laws and accidents here; a law's invariance is different in kind, not in degree, from an accident's. (In particular, a law's range of invariance is not “broader”—at least in the most straightforward sense.) The stability distinctive of the laws is used to explicate what it would mean for there to be multiple grades (or degrees) of physical necessity. Whether there are is for science to discover.

Recent attempts to turn Standard Quantum Theory into a coherent representational system have improved markedly over previous offerings. Important questions about the nature of material systems remain open, however, as current theorizing effectively resolves into a multiplicity of incompatible statements about the nature of physical systems. Specifically, the most cogent proposals to date land in effective empirical equivalence, reviving old anti-realist fears about quantum physics. In this paper such fears are discussed and found unsound. It is argued that nothing of global skeptical or agnostic significance follows from the kind of underdetermination presently encountered in fundamental quantum theory. The case is instructive, however, for what it shows about the characteristics and prospects of scientific realism as a perspective in contemporary philosophy of science.

We examine two approaches to functions: etiological and forward-looking. In the context of functions, we raise the question, familiar to philosophers of mind, about the explanatory role of properties that are not supervenient on the mere dispositional features of a system. We first argue that the question has no easy answer in either of the two approaches. We then draw a parallel between functions and goal directedness. We conclude by proposing an answer to the question: The explanatory importance of nonsupervenient properties (like having the function of doing something, or like being goal-directed) does not lie in any special causal mechanism through which these properties bring about their effects; it lies rather in the different classification of the explananda types that these properties generate.

The case of Semmelweis has been well known since Hempel. More recently, it has been revived by Peter Lipton, Donald Gillies, Alexander Bird, Alex Broadbent, and Raphael Scholl. While these accounts differ on what exactly the case of Semmelweis shows, they all agree that Semmelweis was an excellent reasoner. This widespread agreement has also given rise to a puzzle: why Semmelweis’s views were rejected for so long. I aim to dissolve both this puzzle and the standard view of Semmelweis by showing that, contrary to prevailing opinion, Semmelweis was not the excellent reasoner he has been assumed to be.

As scientists begin to study increasingly complex questions, many have turned to computer simulation to assist in their inquiry. This methodology has been challenged by both analytic modelers and experimentalists. A primary objection of analytic modelers is that simulations are simply too complicated to perform model verification. From the experimentalist perspective it is that there is no means to demonstrate the reality of simulation. The aim of this paper is to consider objections from both of these perspectives, and to argue that a proper understanding and application of robustness analysis is able to resolve them.

Controversies over the innateness of cognitive structures play a persistent role in driving research in philosophy as well as cognitive science, but the appropriate way to understand the category of the innate remains in dispute. The invariantist approaches of Stich and Sober face counterexample cases of traits that, though developing invariantly across different environments, nonetheless are not held by nativism partisans to count as innate. Appeals to canalization (Ariew) or to psychological primitiveness (Samuels) fail to handle this liberalism problem. We suggest a novel approach to innateness: closed process invariantism.

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 (15[1948], pp. 135–75).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. (This literature and its inherent dialectic has been examined and analyzed in close and interesting detail in Wesley Salmon's fine survey of Four Decades of Scientific Explanation.2) 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.

Stars are remarkably absent from reflections on natural kinds and classifications, with gold, tiger, jade, and water getting all the philosophical attention. It is a pity, for interesting philosophical lessons can be drawn from stellar taxonomy as regards two central debates about natural kinds, to wit, the monism/pluralism debate and the realism/antirealism debate. I show in particular that stellar kinds will not please the essentialist monist, nor will it please the pluralist embracing promiscuous realism à la Dupré. I conclude on a more general note by questioning the relationship between taxonomic scientific practice and philosophical doctrines of natural kinds.

Laws are supposed to tell us how physical systems actually behave. The analysis of an important part of physical practice—abstraction—shows, however, that laws describe the behavior of physical systems under very special circumstances, namely when they are isolated. Nevertheless, laws are applied in cases of non-isolation as well. This practice requires an explanation. It is argued that one has to assume that physical systems have dispositions. I take these to be innocuous from an empiricist's standpoint because they can—at least in principle—be measured. Laws can be applied whenever such a disposition is present, they describe how the physical system would behave if the disposition were manifest.

The purpose of this paper is to resolve two paradoxes, which occur in quantum theory, by using the discussion of the theory of measurement presented in two earlier papers by the author [3], [4], [5]. The two paradoxes discussed will be the Schrödinger cat paradox and the Einstein, Podolski, Rosen paradox [2]. An introductory section will be included which summarizes the relevant results from the author's previous papers. Also a discussion will be made regarding the author's interpretation of the density operator.

This is an important book: It is the most sustained defense of a minimalist conception of truth in print. It systematically deals with all of the usual objections to minimalist views of truth (redundancy theories and their ilk), in most cases providing devastating replies to them; and it contains interesting things to say about many issues that are or have been thought to be connected to the topic of truth. Its arguments are lucid and of high quality, and it is broad in scope. I recommend it with enthusiasm.

John Searle's provocative essay, “Minds, Brains, and Programs“ (1980), with its Chinese-room thought experiment (see the Appendix), has generated a great deal of interest and controversy among philosophers, computer scientists, and cognitive scientists.

There is sufficient evidence from more recent experiments in psychology that equal retinal stimulus-elements do not lead to equal experiences and reactions except under certain rather specific conditions. An unsophisticated observer will find himself surprised to be able to cover with his own finger a person entering the door of his living room. When the finger is moved to the right or left, thus doing away with the precise retinal coincidence with the person, the observer will soon become unable to recognize intuitively the actual retinal stimulus equality of the two distant things. This usually holds even for the case when he is making every inner effort towards an antagonistic, analytic perceptual attitude of the type which is used by painters or draughtsmen in order to represent the environmental situation in a similar way as it would project itself on a photographic plate or on a retina.

This article describes one style of functional analysis commonly used in the neurosciences called “task-bound functional analysis.” The concept of function invoked by this style of analysis is distinctive in virtue of the dependence relations it bears to transient environmental properties. It is argued that task-bound functional analysis cannot explain the presence of structural properties in nervous systems. An alternative concept of neural function is introduced that draws on the theoretical neuroscience literature, and an argument is given to show that this alternative concept may help to overcome the explanatory limitations of task-bound functional analysis.

1. Introduction. David Malament (1995) has described a natural and satisfying resolution of the traditional problems of Newtonian cosmology—natural in the sense that it effects the escape by altering Newtonian gravitation theory in a way that leaves its observational predictions completely unaffected. I am in full agreement with his approach. There is one part of his account, however, over which Malament has been excessively modest. The resolution requires a modification to Newtonian gravitation theory. Malament presents the modification as so straightforward as to be automatic. This trivializes the crucial postulate, which I shall call the “relativity of acceleration.” It is a significant physical statement in its own right and requires careful justification. Moreover the postulate proved easy to overlook for decades of discussion of the paradox. It really only becomes natural from the perspective of the newer geometric methods Malament exploits. There the postulate has become a commonplace. My purpose here is to develop the following:

• While Newtonian cosmology can be repaired satisfactorily, in its traditional form it remains deeply troubled. These troubles can be expressed most vividly as the paradoxical contradictions indicated below. They persist in both the integral and differential formulations of Newtonian gravitation theory. (Section 2)

• Malament's careful geometric treatment is necessarily dense. By taking some liberties with precision, his core result can be expressed in a far simpler form. (Section 4)

• Attempts to avoid the resolution Malament describes do lead to disaster. Therefore this episode can be inverted and used as the strongest extant argument for the relativity of acceleration in Newtonian gravitation theory. (Section 5)

In order to judge whether a theory is empirically adequate one must have epistemic access to reliable records of past measurement results that can be compared against the predictions of the theory. Some formulations of quantum mechanics fail to satisfy this condition. The standard theory without the collapse postulate is an example. Bell's reading of Everett's relative-state formulation is another. Furthermore, there are formulations of quantum mechanics that only satisfy this condition for a special class of observers, formulations whose empirical adequacy could only be judged by an observer who records her measurement results in a special way. Bohm's theory is an example. It is possible to formulate hidden-variable theories that do not suffer from such a restriction, but these encounter other problems.

David Sloan Wilson has recently revived the idea of a group mind as an application of group selectionist thinking to cognition. Central to my discussion of this idea is the distinction between the claim that groups have a psychology and what I call the social manifestation thesis—a thesis about the psychology of individuals. Contemporary work on this topic has confused these two theses. My discussion also points to research questions and issues that Wilson's work raises, as well as their connection to externalist conceptions of the mind familiar since the work of Putnam and Burge.