What is required for something to be evidence for a hypothesis? In this fascinating, elegantly written work, distinguished philosopher of science Peter Achinstein explores this question, rejecting typical philosophical and statistical theories of evidence. He claims these theories are much too weak to give scientists what they want--a good reason to believe--and, in some cases, they furnish concepts that mistakenly make all evidential claims a priori. Achinstein introduces four concepts of evidence, defines three of them by reference to "potential" evidence, (...) and characterizes the latter using a novel epistemic interpretation of probability. The resulting theory is then applied to philosophical and historical issues. Solutions are provided to the "grue," "ravens," "lottery," and "old-evidence" paradoxes, and to a series of questions. These include whether explanations or predictions furnish more evidential weight, whether individual hypotheses or entire theoretical systems can receive evidential support, what counts as a scientific discovery, and what sort of evidence is required for it. The historical questions include whether Jean Perrin had non-circular evidence for the existence of molecules, what type of evidence J. J. Thomson offered for the existence of the electron, and whether, as is usually supposed, he really discovered the electron. Achinstein proposes answers in terms of the concepts of evidence introduced. As the premier book in the fabulous new series Oxford Studies in Philosophy of Science, this volume is essential for philosophers of science and historians of science, as well as for statisticians, scientists with philosophical interests, and anyone curious about scientific reasoning. (shrink)
An examination of difficulties in three standard accounts of functions leads to the suggestion that sentences of the form "the function of x is to do y" are used to make a variety of different claims, all of which involve a means-end relationship and the idea of design, or use, or benefit. The analysis proposed enables us to see what is right and also wrong with accounts that analyze the meaning of function statements in terms of good consequences, goals, and (...) etiological explanation. It also enables us to show that function sentences can be used in providing various types of explanations, including, in certain cases, noncausal explanations of the presence of the item with the function. (shrink)
There are two reasons, I claim, scientists do and should ignore standard philosophical theories of objective evidence: (1) Such theories propose concepts that are far too weak to give scientists what they want from evidence, viz., a good reason to believe a hypothesis; and (2) They provide concepts that make the evidential relationship a priori, whereas typically establishing an evidential claim requires empirical investigation.
An a priori thesis about evidence, defended by many, states that the only empirical fact that can affect the truth of an objective evidence claim of the form ‘e is evidence for h’ (or ‘e confirms h to degree r’) is the truth of e; all other considerations are a priori. By examining cases involving evidential flaws, I challange this claim and defend an empirical concept of evidence. In accordance with such a concept, whether, and the extent to which, e, (...) if true, confirms h is an empirical, not a priori, fact. (shrink)
: This paper examines the debate in the late 19th and early 20th centuries over the acceptability of atomic and molecular physics. It focuses on three prominent figures: Maxwell, who defended atomic physics, Ostwald, who initially rejected it but changed his mind as a result of experiments by Thomson and Perrin, and Duhem, who never accepted it. Each scientist defended the position he did in the light of strongly held methodological views concerning empirical evidence. The paper critically evaluates each of (...) these methodological positions. (shrink)
Recent accounts of scientific method suggest that a model, or analogy, for an axiomatized theory is another theory, or postulate set, with an identical calculus. The present paper examines five central theses underlying this position. In the light of examples from physical science it seems necessary to distinguish between models and analogies and to recognize the need for important revisions in the position under study, especially in claims involving an emphasis on logical structure and similarity in form between theory and (...) analogy. While formal considerations are often relevant in the employment of an analogy they are neither as extensive as proponents of this viewpoint suggest, nor are they in most cases sufficient for allowing analogies to fulfill the roles imputed to them. Of major importance, and what these authors generally fail to consider, are physical similarities between analogue and theoretical object. Such similarities, which are characteristic in varying degrees of most analogies actually employed, play an important role in affording a better understanding of concepts in the theory and also in the development of the theoretical assumptions. (shrink)
This volume brings together eleven essays by the distinguished philosopher of science, Peter Achinstein. The unifying theme is the nature of the philosophical problems surrounding the postulation of unobservable entities such as light waves, molecules, and electrons. How, if at all, is it possible to confirm scientific hypotheses about "unobservables"? Achinstein examines this question as it arose in actual scientific practice in three nineteenth-century episodes: the debate between particle and wave theorists of light, Maxwell's kinetic theory of gases, and J.J. (...) Thomson's discovery of the electron. The book contains three parts, each devoted to one of these topics, beginning with an essay presenting the historical background of the episode and an introduction to the philosophical issues. There is an illuminating evaluation of various scientific methodologies, including hypothetico-deductivism, inductivism, and the method of independent warrant which combines features of the first two. Achinstein assesses the philosophical validity of both nineteenth-century and modern answers to questions about unobservables, and presents and defends his own solutions. (shrink)
According to a standard account of evidence, one piece of information is stronger evidence for an hypothesis than is another iff the probability of the hypothesis on the one is greater than it is on the other. This condition, I argue, is neither necessary nor sufficient because various factors can strengthen the evidence for an hypothesis without increasing (and even decreasing) its probability. Contrary to what probabilists claim, I show that this obtains even if a probability function can take these (...) evidential factors into account in ways they suggest and yield a unique probability value. Nor will the problem be solved by appealing to second-order probabilities. (shrink)
Theories of explanation are characterized as being either pragmatic or non-pragmatic, without a clear sense of what this is supposed to mean. The present paper offers a definition of a "pragmatic explanation-sentence", and in terms of this, of a "pragmatic theory of explanation". It is argued that van Fraassen's theory of explanation, despite claims to the contrary, is not genuinely pragmatic. By contrast, the author's own "illocutionary" theory is pragmatic. Attention is devoted particularly to sentences of the form "E is (...) a good explanation of q", which, it is urged, are pragmatic in a strong sense. In defense of this claim, and of the advantages of a pragmatic account generally, appeal is made to Rutherford's 1911 subatomic explanation of the results of his scattering experiments. Implications of a pragmatic theory are drawn for the debate between realists and anti-realists and absolutists and relativists. (shrink)
In this book, Peter Achinstein proposes and defends several objective concepts of evidence. He then explores the question of whether a scientific method, such as that represented in the four "Rules for the Study of Natural Philosophy" that Isaac Newton invoked in proving his law of gravity, can be employed in demonstrating how the proposed definitions of evidence are to be applied to real scientific cases.
By reference to Maxwell's kinetic theory, one feature of hypothetico-deductivism is defended. A scientist need make no inference to a hypothesis when he first proposes it. He may have no reason at all for thinking it is true. Yet it may be worth considering. In developing his kinetic theory there were central assumptions Maxwell made (for example, that molecules are spherical, that they exert contact forces, and that their motion is linear) that he had no reason to believe true. In (...) this paper I develop a position that explains why they were worth considering, and that rejects the retroductive position that a hypothesis is worth considering when, if true, it would explain the observed data. (shrink)
In response to a charge of subjectivism, Kuhn in his Postscript emphasizes the importance of "values" (accuracy, simplicity, explanatory power, etc) that are shared by scientists generally. However, Kuhn adds, these values are applied differently by different scientists. By employing a comparison with partially subjective views of Carnap on confirming evidence, this paper raises questions about Kuhn's position on values by considering ways it might be interpreted as subjective and ways it may not.