Two strategies for using a model as “null” are distinguished. Null modeling evaluates whether a process is causally responsible for a pattern by testing it against a null model. Baseline modeling measures the relative significance of various processes responsible for a pattern by detecting deviations from a baseline model. When these strategies are conflated, models are illegitimately privileged as accepted until rejected. I illustrate this using the neutral theory of ecology and draw general lessons from this case. First, scientists cannot draw certain conclusions using null modeling. Second, these conclusions follow using baseline modeling, but doing so requires more evidence.

Late nineteenth-century opponents of atomism questioned whether the evidence required any notion of an atom. In this spirit, Duhem developed an account of the import of chemical formulas that is clearly neutral on the atomic question rather than antiatomistic. The argument is supplemented with specific inadequacies of atomic theories of chemical combination and considerably strengthened by the theory of chemical combination provided by thermodynamics. Despite possible counterevidence available at the time, which should have tempered some of Duhem's concluding remarks, there was no atomic theory of chemical combination, which is wholly a product of the twentieth century.

In Chapter 4 of [2] Grünbaum sets out to refute Einstein's philosophy of physical geometry. The latter's theory is seen as lying within the tradition of “anti-empiricist conventionalism” of Duhem and Quine as opposed to the “qualified empiricism” of Poincaré, Carnap and Reichenbach. Consequently Grünbaum sets the stage for his critique of Einstein by discussing certain of the views of these other thinkers. But in these preliminary discussions the various theses are confused and misrepresented in such a way as to make it almost impossible to evaluate Grünbaum's final treatment of Einstein's thesis. For this reason I will deal only with those parts of this chapter in which the roots of Grünbaum's confusion are to be found. This will involve analyses of two theories which are not clearly distinguished by Grünbaum. The first is Duhem's denial of the “crucial experiment” in physics; the second is Quine's version of “pragmatism.”

P. Kitcher's unification theory of explanation appears to endorse a reductionistic view of scientific explanation that is inconsistant with scientific practice. In this paper, I argue that this appearance is illusory. The existence of multiply realizable generalizations enable the unification theory to also count many high-level accounts as explanatory.

A previous paper of mine, that criticized Suppes' probabilistic theory of causality, was in turn criticized by Deborah Rosen. This paper is a development of my argument and an answer to Rosen. It is argued that the concept of causation is used in contemporary science in a way that presupposes determinism. It is shown that deterministic assumptions are necessary for inferences from generic to individual causal relations and for various kinds of eliminative arguments.

Friedman and Putnam have argued (Friedman and Putnam 1978) that the quantum logical interpretation of quantum mechanics gives us an explanation of interference that the Copenhagen interpretation cannot supply without invoking an additional ad hoc principle, the projection postulate. I show that it is possible to define a notion of equivalence of experimental arrangements relative to a pure state φ, or (correspondingly) equivalence of Boolean subalgebras in the partial Boolean algebra of projection operators of a system, which plays a role in the Copenhagen explanation of interference analogous to the role played by the material equivalence, given φ, of certain propositions in the Friedman-Putnam quantum logical analysis. I also show that the quantum logical interpretation and the Copenhagen interpretation are equally capable of avoiding the paradoxical conclusion of the Einstein-Podolsky-Rosen argument (Einstein, Podolsky, and Rosen 1935). Thus, neither interference phenomena nor the correlations between separated systems provide a test case for distinguishing between the relative acceptability of the Copenhagen interpretation and the quantum logical interpretation as explanations of quantum effects.

Mathematical methods in biology occupy a somewhat peculiar position, and the attitude of many biologists toward them is similar to that of many practical engineers toward what is called pure scientific research. The modern progressive engineer recognizes the value of pure science, which seeks for truth regardless of any possibility of practical applications; yet he still frequently shows a definite dislike towards such investigations. The whole history of civilization demonstrates that discoveries which, at the time they were made, did not show any signs of the possibility of being turned into practical use, now lie at the basis of many useful engineering devices. As Professor R. A. Millikan has said, we owe our present-day civilization to Galileo. Every educated person, be he pure scientist or engineer, recognizes this fact. And yet the frame of mind of the “practical” man is not too receptive to investigations which do not show at least some remote prospects of practical applications. Unless he can see at least hypothetically some practical results of such research, he will not give it his whole-hearted enthusiasm. The ultimate criterion in the evaluation of any research still remains its practical use. Those pure scientists who have had close contact with what is called “industrial research” know only too well the truth of the above statement.

Ten years ago the civilized world was shocked out of an unwarranted confidence in the victory of science over superstition by the news that Tennessee had outlawed the teaching of man's evolutionary origin. Within the next three years both Mississippi and Arkansas joined Tennessee in defense of Biblical truth against the scepticism of science. The furor raised by the dramatic clashes between William Jennings Bryan and Clarence Darrow at the Scopes Trial in Dayton, Tennessee, has now become a faded memory. The struggle between Fundamentalists and Modernists has died down, though the embers still smoulder; and few ever think of the issues then raised, now that war and fascism threaten civilization.

Factual statements that might qualify for the status of law statements are classed from various philosophically relevant standpoints (referents, precision, structure of predicates, extension, systemicity, inferential power, inception, ostensiveness, testability, levels, and determination categories). More than seven dozen of not mutually exclusive kinds of lawlike statements emerge. Strictly universal and counterfactually powerful statements are seen to constitute just one kind of lawlike statements; classificatory and some statistical laws, e.g., are shown not to comply with the requirements of universality and counterfactual force.

Conditions for lawlike statements to be called laws are then examined, and a liberal criterion of lawfulness is finally proposed, which reads thus: A proposition is a law statement if and only if it is a posteriori (not logically true), general in some respect (does not refer to unique objects), has been satisfactorily corroborated for the time being in some domain, and belongs to a theory (whether adult or embryonic). It is claimed that criteria of laws change alongside with the emergence of new usages of the term ‘law’, and that by adopting a liberal criterion of lawfulness we would conform to contemporary usage and would cease inhibiting the search for regularities in the sciences of man.

The logical theory of branching space-times, which provides a relativistic framework for studying objective indeterminism, remains mostly disconnected from discussions of space-time theories in philosophy of physics. Earman has criticized the branching approach and suggested “pruning some branches from branching space-time.” This article identifies the different—order-theoretic versus topological—perspective of both discussions as a reason for certain misunderstandings and tries to remove them. Most important, we give a novel, topological criterion of modal consistency that usefully generalizes an earlier criterion, and we introduce a differential-geometrical version of branching space-times as a non-Hausdorff (generalized) manifold.

This paper brings needed clarity to the influential view that species are cohesive entities held together by gene flow, and then develops an empirical argument against that view: Neglected data suggest gene flow is neither necessary nor sufficient for species cohesion. Implications are discussed.

I reinterpret Bohr's attitude towards quantum mechanical formalism and its empirical content, based on his understanding of the correspondence principle and its approximate applicability. I suggest that Bohr understood complementarity as a limitation imposed by the commutation relations upon the applicability of the idealizations which had grounded the use of the correspondence principle. By discussing this interpretation against the contemporary background of discussions regarding “naïve realism” about operators (as observables), I suggest that a Bohrian view on the empirical content of quantum mechanical operators may provide a middle ground between complete contextualism and an untenable realism about quantum properties.

The Bell 1964 theorem states that nonlocality is a necessary feature of hidden variable theories that reproduce the statistical predictions of quantum mechanics. In view of the no-go theorems for non-contextual hidden variable theories already existing up to 1964, and due to Gleason and Bell, one is forced to acknowledge the contextual character of the hidden variable theory which the Bell 1964 theorem refers to. Both the mathematical and the physical justifications of this contextualism are reconsidered. Consequently, the role of contextualism in recent no-hidden-variables proofs and the import of these proofs are investigated. With reference to the physical intuition underlying contextualism, the possibility is considered whether a context-dependence of individual measurement results is compatible with context-independence of the statistics of measurement results.

Mechanisms play an important role in many sciences when it comes to questions concerning explanation, prediction, and control. Answering such questions in a quantitative way requires a formal representation of mechanisms. Gebharter’s “A Formal Framework for Representing Mechanisms?” suggests to represent mechanisms by means of arrows in an acyclic causal net. In this article we show how this approach can be extended in such a way that it can also be fruitfully applied to mechanisms featuring causal feedback.

Although it is difficult to exaggerate the similarities between the philosophical doctrines of contemporary scientific empiricists and those which were expounded by Sextus Empiricus, the Greek physician and sceptic of the third century A. D., Sextus seems to have been neglected by most historians of empiricism. An account of his position may be of some pertinence at the present time, for a striking parallel can be drawn without any distortion. His most significant contributions are: first, the positivistic and behavioristic theory of signs which he opposed to the metaphysical theory of the Stoics; secondly, his discussion of phenomenalism and its relation to common sense claims to knowledge; and, thirdly, his account of the controversy over the principle of extensionality in logic, where the anticipation of contemporary doctrines is perhaps most remarkable.

Grünbaum has argued that the Lorentz-Fitzgerald contraction hypothesis is not ad hoc since the Kennedy-Thorndike experiment can be used to provide a test that is significantly different from that provided by the Michelson-Morley experiment. In the first part of the paper, I show that the differences claimed by Grünbaum to hold between these two experiments are not sufficient for establishing independent testability. A dilemma is developed: either the Kennedy-Thorndike experiment, because of experimental realities, cannot test the uncontracted Fresnel aether theory, or if experimental difficulties are ignored, the Kennedy-Thorndike experiment degenerates into a version of the Michelson-Morley experiment. The second part of the paper is a feasibility study of the prospects for defining experimental types according to aims of measurement and determination. This approach is applied to the contraction hypothesis, where it is suggested that the usual analysis of independent testability be modified.

In order to account for the actual function of analogue models in extending theories to new domains, we argue that it is necessary to analyze the inference involved into a complex two dimensional form. This form must go horizontally from descriptions of entities used as a model to redescriptions of entities in the new domain, and it must go vertically from an observation language to a theoretical language having a different and exclusive logical syntax. This complex inference can only be intelligible if we interpret theoretical terms in a platonic manner, a la Körner.

This paper explores versions of agency or manipulability theories of causation and argues that they are unacceptable both for the well-known reasons of their anthropomorphism, limited scope, and circularity and because they are subsumed by an alternative “independence” theory of causation, which is free of these difficulties.