This innovative book focuses on the development of the gene theory as a case study in scientific creativity.

Design research programs attempt to bring together the properties of available materials and the demands derived from intended applications. The logic of problem states and state transitions in such programs, including assessment criteria and heuristic principles, is described in settheoretic terms, starting with a naive model comprising an intended profile and the operational profile of a prototype. In a first concretization the useful distinction between structural and functional properties is built into the model. In two further concretizations the inclusion of (...) potential applications is motivated and described for the case of drug research as well as the inclusion of potential realizations for the case of complex products. Next, another line of concretization of the naive model, the incorporation of potentially relevant properties, is sketched. Then the partial analogy between product- and truth-approximation is indicated. We conclude with some remarks about the usefulness of our models for products reaching the market in comparison to the the so-called social construction of technology approach. (shrink)

By applying research in artificial intelligence to problems in the philosophy of science, Paul Thagard develops an exciting new approach to the study of scientific reasoning. This approach uses computational ideas to shed light on how scientific theories are discovered, evaluated, and used in explanations. Thagard describes a detailed computational model of problem solving and discovery that provides a conceptually rich yet rigorous alternative to accounts of scientific knowledge based on formal logic, and he uses it to illuminate such topics (...) as the nature of concepts, hypothesis formation, analogy, and theory justification. (shrink)

The first systematic study of the aesthetic evaluations that scientists pass on their theories.

he formalization of abductive reasoning is still an open question: there is no general agreement on the boundary of some basic concepts, such as preference criteria for explanations, and the extension to first order logic has not been settled.Investigating the nature of abduction outside the context of resolution based logic programming still deserves attention, in order to characterize abductive explanations without tailoring them to any fixed method of computation. In fact, resolution is surely not the best tool for facing meta-logical (...) and proof-theoretical questions.In this work the analysis of the concepts involved in abductive reasoning is based on analytical proof systems, i.e. tableaux and Gentzen-type systems. A proof theoretical abduction method for first order classical logic is defined, based on the sequent calculus and a dual one, based on semantic tableaux. The methods are sound and complete and work for full first order logic, without requiring any preliminary reduction of formulae into normal forms. In the propositional case, two different characterizations are given for abductive explanations, each of them being the declarative counterpart of a different algorithm for the generation of explanations. The first one corresponds the generation of the whole set of minimal and consistent explanations, where minimality is checked by comparison with the other elements of the set. The second characterization corresponds to a algorithm for generating a single minimal explanation that is consistent with the theory.The first order versions of the abductive systems make use of unification and dynamic herbrandization/skolemization of formulae. The construction of the abduced formula is pursued by means of de-skolemization. The first order methods are very loose in discarding explanations that are not minimal In fact, the question of minimality in first order abduction is a main issue. As usually defined, minimality is undecidable, for two different reasons: determining whether an explanation is better than another one is in general undecidable; the set of explanations may be infinite. Moreover, because of , a minimal element may not exist. Such problems suggest that the minimality requirement should be relaxed, possibly defining it w.r.t. a stronger relation than logical consequence. (shrink)

Philosophers of science as divergent as the inductivist Carnap and the deductivist Popper share the notion that the (logical) content of a proposition is given by its consequence class. I claim that this notion of content is (a) unintuitive and (b) inappropriate for many of the formal needs of philosophers of science. The basic problem is that given this notion of content, for any arbitrary p and q, [(p ∨ q)] will count as part of the content of both p (...) and q. In other words, any arbitrary p and q share some common content. This notion of content has disastrous effects on, for instance, Carnap's attempts to explicate the notion of confirmation in terms of probabilistic favorable relevance, and Popper's attempts to define verisimilitude. After briefly reviewing some of the problems of the traditional notion of content I present an alternative notion of (basic) content which (a) better fits our intuitions about content and (b) better serves the formal needs of philosophers of science. (shrink)

The main formal notion involved in qualitative truth approximation by the HD-method, viz. ‘more truthlike’, is shown to not only have, by its definition, an intuitively appealing ‘model foundation’, but also, at least partially, a conceptually plausible ‘consequence foundation’. Moreover, combining the relevant parts of both leads to a very appealing ‘dual foundation’, the more so since the relevant methodological notions, viz. ‘more successful’ and its ingredients provided by the HD-method, can be given a similar dual foundation. According to the (...) resulting dual foundation of ‘naive truth approximation’, the HD-method provides successes (established true consequences) and counterexamples (established wrongly missing models) of theories. Such HD-results may support the tentative conclusion that one theory seems to remain more successful than another in the naive sense of having more successes and fewer counterexamples. If so, this provides good reasons for believing that the more successful theory is also more truthlike in the naive sense of having more correct models and more true consequences. (shrink)