Bas C. van Fraassen presents an original exploration of how we represent the world.

Suppe, F. The search for philosophic understanding of scientific theories (p. [1]-241)--Proceedings of the symposium.--Bibliography, compiled by Rew A. Godow, Jr. (p. [615]-646).

Metaphysicians speak of laws of nature in terms of necessity and universality; scientists, in terms of symmetry and invariance. In this book van Fraassen argues that no metaphysical account of laws can succeed. He analyzes and rejects the arguments that there are laws of nature, or that we must believe there are, and argues that we should disregard the idea of law as an adequate clue to science. After exploring what this means for general epistemology, the author develops the empiricist (...) view of science as a construction of models to represent the phenomena. (shrink)

It is now part and parcel of the official philosophical wisdom that models are essential to the acquisition and organisation of scientific knowledge. It is also generally accepted that most models represent their target systems in one way or another. But what does it mean for a model to represent its target system? I begin by introducing three conundrums that a theory of scientific representation has to come to terms with and then address the question of whether the semantic view (...) of theories, which is the currently most widely accepted account of theories and models, provides us with adequate answers to these questions. After having argued in some detail that it does not, I conclude by pointing out in what direction a tenable account of scientific representation might be sought. (shrink)

The structure of evolutionary theory has proved difficult to characterize. Most available analyses focus on the existence of evolutionary laws and on the axiomatizability of the theory; such analyses pay insufficient attention to mathematical evolutionary models and their structure, and to the structural complications arising from the variety of evolutionary sub-theories. ;The primary goal of this dissertation is to introduce and develop an analysis of the structure of evolutionary theory that is both precise and useful. The secondary goal is to (...) offer further evidence of the appropriateness and utility of the semantic view of theories, as developed by P. Suppes, B. C. van Fraassen, and F. Suppe, in which the theory is viewed as a family of related mathematical models. ;After reviewing the semantic approach, I provide a formal framework for describing and distinguishing among population genetics models. The interrelations among the models are described through a set of notions developed and made precise through the analysis of several evolutionary sub-theories, including genic selection and species selection. The framework of model specification, combined with the notions describing formal relations among models, are offered as a system capable of describing any part or aspect of the structure of evolutionary theory. ;Finally, I present a view of confirmation that relies on the distinctions present in the above system of theory description. I argue that this view of confirmation has two advantages over a hypothetico-deductive view of confirmation. First, it is possible to establish the reasonableness of viewing a variety of evidence as a form of confirmation. Second, as I show in the analysis of a controversial model, distinctions can be made due to the subtlety of the view that do not appear under the usual approaches. ;I conclude that a semantic approach to the structure of theories offers a natural, precise framework for the characterization of contemporary evolutionary theory. As such, it may provide a means with which progress on outstanding theoretical and philosophical problems can be achieved. (shrink)

We develop a duality theory for small Boolean pretoposes in which the dual of the [italic capital]T is the groupoid of models of a Boolean pretopos [italic capital]T equipped with additional structure derived from ultraproducts. The duality theorem states that any small Boolean pretopos is canonically equivalent to its double dual. We use a strong version of the duality theorem to prove the so-called descent theorem for Boolean pretoposes which says that category of descent data derived from a conservative pretopos (...) morphism between Boolean pretoposes is canonically equivalent to the domain-pretopos. The descent theorem contains the Beth definability theorem for classical first order logic. Moreover, it gives, via the standard translation from the language of categories to symbolic logic, a new definability theorem for classical first order logic concerning set-valued functors on models, expressible in purely syntactical (arithmetical) terms. (shrink)

Traditionally a scientific theory is viewed as based on universal laws of nature that serve as axioms for logical deduction. In analyzing the logical structure of evolutionary biology, Elisabeth Lloyd argues that the semantic account is more appropriate and powerful. This book will be of interest to biologists and philosophers alike.

Recently several philosophers of science have proposed what has come to be known as the semantic account of scientific theories. It is presented as an improvement on the positivist account, which is now called the syntactic account of scientific theories. Bas van Fraassen claims that the syntactic account does not give a satisfactory definition of "empirical adequacy" and "empirical equivalence". He contends that his own semantic account does define these notations acceptably, through the concept of "embeddability", a concept which he (...) claims cannot be defined syntactically. Here, I define a syntactic relation which corresponds to the semantic relation of "embeddability". I suggest that the critical differences between the positivist account and van Fraassen's account have nothing to do with the distinction between semantics and syntax. (shrink)

Recently some philosophers have urged that connectionist artificial intelligence is (potentially) eliminative for the propositional attitudes of folk psychology. At the same time, however, these philosophers have also insisted that since philosophy of science has failed to provide criteria distinguishing ontologically retentive from eliminative theory changes, the resulting eliminativism is not principled. Application of some resources developed within the semantic view of scientific theories, particularly recent formal work on the theory reduction relation, reveals these philosophers to be wrong in this (...) second contention, yet by and large correct in the first. (shrink)

We are used to talking about the “structure” posited by a given theory of physics, such as the spacetime structure of relativity. What is “structure”? What does the mathematical structure used to formulate a theory tell us about the physical world according to the theory? What if there are different mathematical formulations of a given theory? Do different formulations posit different structures, or are they merely notational variants? I consider the case of Lagrangian and Hamiltonian classical mechanics. I argue that, (...) contrary to standard wisdom, these are not genuinely equivalent theories: they differ in statespace structure. I suggest that we should be realists about statespace structure. (shrink)

One can (for the most part) formulate a model of a classical system in either the Lagrangian or the Hamiltonian framework. Though it is often thought that those two formulations are equivalent in all important ways, this is not true: the underlying geometrical structures one uses to formulate each theory are not isomorphic. This raises the question whether one of the two is a more natural framework for the representation of classical systems. In the event, the answer is yes: I (...) state and prove two technical results, inspired by simple physical arguments about the generic properties of classical systems, to the effect that, in a precise sense, classical systems evince exactly the geometric structure Lagrangian mechanics provides for the representation of systems, and none that Hamiltonian mechanics does. The argument not only clarifies the conceptual structure of the two systems of mechanics, their relations to each other, and their respective mechanisms for representing physical systems. It also provides a decisive counter-example to the semantical view of physical theories, and one, moreover, that shows its crucial deficiency: a theory must be, or at least be founded on, more than its collection of models (in the sense of Tarski), for a complete semantics requires that one take account of global structures defined by relations among the individual models. The example also shows why naively structural accounts of theory cannot work: simple isomorphism of theoretical and empirical structures is not rich enough a relation to ground a semantics. (shrink)

Da Costa and French explore the consequences of adopting a 'pragmatic' notion of truth in the philosophy of science. Their framework sheds new light on issues to do with belief, theory acceptance, and the realism-antirealism debate, as well as the nature of scientific models and their heuristic development.

Multiply realizable properties are those whose realizers are physically diverse. It is often argued that theories which contain them are ipso facto irreducible. These arguments assume that physical explanations are restricted to the most specific descriptions possible of physical entities. This assumption is descriptively false, and philosophically unmotivated. I argue that it is a holdover from the late positivist axiomatic view of theories. A semantic view of theories, by contrast, correctly allows scientific explanations to be couched in the most perspicuous, (...) powerful language available. On a semantic view, traditional notions of multiple realizability are thus very hard to motivate. At best, one must abandon either the idea that multiple realizability is an interesting scientific notion, or else admit that multiply realizable properties do not automatically block scientific reductions. (shrink)

Much if not most recent literature in philosophy of biology concerns the extent to which biological theories conform to what is known as the "received" philosophical view of scientific theories, a descendant of the logical-empiricist view of theories. But the received view currently faces a competitor--a very different view of theories known as the "semantic" view. It is argued here that the semantic view is more sensitive to the nature and limitations of evolutionary theory than is the received view. In (...) particular, the semantic view better accomodates the fact that evolutionary theory is bound to change as a result of the evolutionary process itself. This unusual feature of evolutionary theory provides a good reason for reconsidering the received view and paying close attention to the semantic view. (shrink)

From a logical point of view, Stone duality for Boolean algebras relates theories in classical propositional logic and their collections of models. The theories can be seen as presentations of Boolean algebras, and the collections of models can be topologized in such a way that the theory can be recovered from its space of models. The situation can be cast as a formal duality relating two categories of syntax and semantics, mediated by homming into a common dualizing object, in this (...) case 2.In the present work, we generalize the entire arrangement from propositional to first-order logic, using a representation result of Butz and Moerdijk. Boolean algebras are replaced by Boolean categories presented by theories in first-order logic, and spaces of models are replaced by topological groupoids of models and their isomorphisms. A duality between the resulting categories of syntax and semantics, expressed primarily in the form of a contravariant adjunction, is established by homming into a common dualizing object, now Sets, regarded once as a boolean category, and once as a groupoid equipped with an intrinsic topology.The overall framework of our investigation is provided by topos theory. Direct proofs of the main results are given, but the specialist will recognize toposophical ideas in the background. Indeed, the duality between syntax and semantics is really a manifestation of that between algebra and geometry in the two directions of the geometric morphisms that lurk behind our formal theory. Along the way, we give an elementary proof of Butz and Moerdijkʼs result in logical terms. (shrink)

The central thesis of this book is that the semantic conception is a logical methodologically and heuristically richer and more accurate account of scientific theorizing, and in particular of theorizing in evolutionary biology, than the ...

Many philosophers of psychology fail to appreciate the constructivist process of science as well as its pragmatic aspects. A well-developed philosophy of science helps to clear many conceptual confusions. However, ridding ourselves of popular complaints only opens more sophisticated worries regarding how we generalize specific events and how we use those generalizations to build physical systems and abstract models. These questions can still be answered though by realizing that science is largely a social enterprise, and how and what we explain (...) depends a great deal upon who is asking the question of whom and when. (shrink)