Verificationism

Abstract: Preface 1 A Model Discipline 11 The Model in Political Science 12 Metaphors and Analogies, Fables and Fictions 13 The broad themes of the book 131 Science is not what we think it is 132 Current practice is not "philosophy-free" 133 Models are objects 134 Models are not tested with data 135 Explanation 14 Plan of the Book 15 What this Book is Not 2 The Science in Political Science 21 Introduction 22 What Political Scientists Say They Are Doing 23 Hypothetico-Deductivism 24 Problems with H-D 241 Deductions are Truth-Preserving 242 Data Can't Speak for Themselves 243 Other Problems with H-D 25 How We Got Here 251 Logical Positivism 252 Pathologies of Rational Choice 253 Methods and Models 254 The Empirical Implications of Theoretical Models 26 Conclusion 3 What is a Model? 31 Introduction 32 Models as Maps 33 A Few Examples 34 The Received View of Scientific Theories 35 The Semantic Conception of Scientific Theories 36 The Model-Based View of Scientific Theories 37 Models and Theories 38 Conclusion 4 Theoretical Models 41 Introduction 42 Aspects of Theoretical Models 43 The Purposes of Models 431 Foundational Models 432 Organizational Models 433 Exploratory Models 434 Predictive Models 44 Judging a Theoretical Model 441 Prediction is the Wrong Standard (Usually) 442 The Illusion of Precise Standards 443 Dimensions of Usefulness 45 Conclusion 5 Empirical Models 51 Introduction 52 What is an Empirical Model? 521 A Model-Based Understanding 53 The Purposes of Empirical Models 54 The Illogic of Theory Testing 541 Falsificationism 542 Verificationism 543 Bayesian Confirmation 55 The Other Uses of Empirical Modeling 56 Conclusion 6 Explanation 61 Introduction 62 Existing justifications 63 Explanation 631 What constitutes an explanation? 632 Explanation in Political Science 64 Models as explanations 65 Choosing among explanations 651 Comparative Model Testing 652 Is choosing necessary? 66 Conclusion 7 Conclusion 71 Introduction 72 Review of the argument 73 Issues and counterarguments Bibliography

Abstract: Dorothy Edgington has recently helped an argument of Fitch's against verificationism to emerge from ill-merited obscurity.1 Roughly speaking, the argument shows that not obviously silly forms of verificationism entail obviously silly forms of it. Edgington treats the argument as a paradox because she holds that we must retain some form of verificationism in order to do justice to certain considerations about what it is to grasp a concept, considerations which seem to owe something to Michael Dummett. She ingeniously proposes a modification of the verificationist schema that blocks Fitch's argument. I shall argue that if there is a way of reading the modified schema as a not obviously silly form of verificationism, it has not yet been revealed. A not obviously silly form of verificationism says, roughly, that all truths are knowable. It can be formalized by the schema:

Abstract: Scientists observe nature, search for generalizations, and provide explanations for why the world is as it is. Generalizations are of two kinds. The first are descriptive and inductive, such as Boyle's Law. They are derived from observations and therefore refer to observables (in this case, pressure and volume). The second are often imaginative and form the axioms of a deductive theory, such as Newton's Laws of Motion. They often refer to unobservables (e.g. inertia and gravitation). Biology has many inductive generalizations (e.g. Bergmann's Rule and 'all cells arise from preexisting cells') but few, if any, recognized universal laws and virtually no deductive theory. Many biologists and philosophers of biology have agreed that predictive theory is inappropriate in biology, which is said to be more complex than physics, and that one can have nonpredictive explanations, such as the neo-Darwinian Theory of Evolution by Natural Selection. Other philosophers dismiss nonpredictive, explanatory theories, including evolutionary 'theory', as metaphysics. Most biologists do not think of themselves as philosophers or give much thought to the philosophical basis of their research. Nevertheless, their philosophy shows in the way they do research. The plethora of ad hoc (i.e. not universal) hypotheses indicates that biologists are reluctant inductivists in that the search for generalization does not have a high priority. Biologists test their hypotheses by verification. Theoretical physicists, in contrast, are deductive unifiers and test their explanatory hypotheses by falsification. I argue that theoretical biology (concerned with unobservables, such as fitness and natural selection) is not scientific because it lacks universal laws and predictive theory. In order to make this argument, I review the differences between verificationism and falsificationism, induction and deduction, and descriptive and explanatory laws. I show how these differ with a specific example of a successful and still useful (even if now superseded as explanatory) deductive theory, Newton's Theory of Motion. I also review some of the philosophical views expressed on these topics because philosophers seem to be even more divided than biologists, which is not at all helpful. The fact that biology does not have predictive theories does not constitute irrefutable evidence that it cannot have them. The only way to falsify this philosophical hypothesis, however, is to produce a predictive theory with universal biological laws. I have proposed such a theory, but it has been presented piecemeal. At the end of this paper, I bring the pieces together into a deductive theory on the evolution of life history traits (e.g. clutch size, mating relationships, sexual size dimorphism).

Abstract: Rudolf Carnap's Der logische Aufbau der Welt', written largely in the years 1922-25 and published in 1928, is generally-and rightlyregarded as one of the most important classics of twentieth century positivist thought. But what exactly is the importance of this great work? Precisely where does its significance lie? The most widely accepted view of this question, I think, runs as follows. Central to twentieth century positivism is the doctrine of verificationism: the doctrine that the cognitive meaning of all scientific statements must ultimately consist in their consequences for actual and possible sense experiences. And it is this radically empiricist doctrine, above all, that forms the basis for the notorious anti-metaphysical attitude of twentieth century positivism: in virtue of their unverifiability, metaphysical statements are deprived of all cognitive meaning as well. Yet this radically empiricist program also requires a positive construction, for one must show how the nonmetaphysical statements of science and everyday life are actually translatable into terms referring only to sense experiences. In other words, twentieth century positivism requires a phenomenalistic reduction. The Aufbau, on this reading, is primarily important for its attempt at just such a phenomenalistic reduction: Radical reductionism, conceived now with statements as units, set itself the task of specifying a sense-datum language and showing how to translate the rest of significant discourse, statement by statement, into it. Carnap embarked on this project in the Aufbau.2 On this reading, then, the Aufbau is best seen as an exceptionally detailed and rigorous attempt to execute concretely the program of Russell's Our Knowlec4'e of the External World (1914):