When a theory is confronted with a problem such as a paradox, an empirical anomaly, or a vicious regress, one may change part of the theory to solve that problem. Sometimes the proposed solution is considered ad hoc. This paper gives a new definition of ‘ad hoc solution’ as used in both philosophy and science. I argue that a solution is ad hoc if it fails to live up to the explanatory requirements of a theory because the solution is not (...) backed by an explanation or because it does not diagnose the problem. Ad hoc solutions are thus magical: they solve a problem without providing insight. This definition helps to explain both why ad hoc solutions are bad and why there may be disagreement about cases. (shrink)

In this paper I comment on a recent paper by [Scerri, E., & Worrall, J. . Prediction and the periodic table. Studies in History and Philosophy of Science, 32, 407–452.] about the role temporally novel and use-novel predictions played in the acceptance of Mendeleev’s periodic table after the proposal of the latter in 1869. Scerri and Worrall allege that whereas temporally novel predictions—despite Brush’s earlier claim to the contrary—did not carry any special epistemic weight, use-novel predictions did indeed contribute to (...) the acceptance of the table. Although I agree with their first claim, I disagree with their second. In order to spell out my disagreement, I not only revisit Scerri and Worrall’s interpretation of crucial historical evidence they have cited in support of the ‘heuristic account’ of use-novel predictions, but I also criticise the latter on general grounds.Keywords: Periodic table; Dmitri Mendeleev; Noble gases; Use-novel predictions; Heuristic account; Ad hoc hypotheses. (shrink)

Jarrett Leplin in A Novel Defense of Scientific Realism (1997) argues that if the thesis of empirical equivalence is cogent, then the thesis of underdetermination cannot even get off the ground. Part of Leplin's argument rests on the claim that auxiliary hypotheses can be independently confirmed, thus enabling us to determine the epistemic worth of a theory. This, in turn, helps in determining about what we should be realists. Leplin's claims are demonstrated to be problematic. Leplin wants, inconsistently, to use (...) only those auxiliary hypotheses which dovetail with confirmed theories. Finally, a detail of Leplin's argument is found wanting. (shrink)

One of the things I attempted to do in my paper on independent testability was to illustrate convincingly the very real difficulties of distinguishing between the accidental and essential features of a scientific experiment. The importance of this distinction is that independent testability presumably requires differences that are essential and telling and not merely accidental reflections of existing experimental technique or of the procedural preferences of the experimenter. In the case of the Michelson-Morley and Kennedy-Thorndike experiments, I showed, following a (...) suggestion of M. G. Evans, that Grünbaum's attempt to distinguish these two experiments does not work. I also showed that certain obvious and natural variations of Grünbaum's approach do not adequately distinguish these experiments. So, for example, it will not do simply to claim that MM is characterized by equal arms and KT by unequal arms, since equal arms are required for MM only in the absence of adequate photographic registration methods. But if these methods are not available then KT is not possible. Conversely, if these methods are available, then while both MM and KT are experimentally possible, MM need not be restricted to equal arms. (shrink)

What does it mean for a hypothesis to be ad hoc? One prominent account has it that ad hoc hypotheses have no independent empirical support. Others have viewed ad hoc judgements as subjective. Here I critically review both of these views and defend my own Coherentist Conception of Ad hocness by working out its conceptual and descriptive attractions.

“Naturalized epistemology” is a recent attempt to transform the theory of knowledge into a branch of natural science. Traditional epistemologists object to this proposal on the grounds that it eliminates the distinctively philosophical content of epistemology. In this thesis, I argue that traditional philosophers are justified in their reluctance to accept naturalism, but that their ongoing inability to refute it points to deeper problems inherent in traditional epistemology. I establish my thesis first by critiquing three versions of naturalism, showing that (...) each version either fails to implement its objectives consistently or starts from dubious objectives. “Optimistic naturalism” attempts to use naturalistic methods to give positive answers to traditional epistemological questions (such as by affirming that our beliefs can be justified). This fails because the form of traditional questions requires the concept “belief,” a concept that I argue naturalistic methodology cannot countenance (because of the severe constraints of naturalistic semantic theory). “Pessimistic naturalism,” the version advocated by Quine, is more consistent with naturalistic methodology, but fails because hidden behind its conclusions are assumptions (such as the underdetermination thesis) that cannot themselves be naturalized in the full context of scientific evidence. A final attempt to naturalize epistemology, deflationary naturalism, dispenses with traditional questions entirely, urging that the terms “knowledge” and “justification” be taken as mere pragmatic devices whose use can, nevertheless, be studied scientifically. Curiously, this view fails to take account of important facts about the actual use of those terms, as studied by psychologists. In the end, despite problems with each of these versions, traditional philosophers can learn something from their encounter with naturalism. In the course of showing how various naturalistic doctrines cannot themselves be naturalized, I identify the flaws in traditional epistemology (such as its reliance on a priorism, and its resulting inability to articulate a workable empirical foundationalist theory of justification) that make naturalism harder to challenge. These flaws must be corrected if philosophers are to preserve the autonomy of their discipline. (shrink)

The point of the traditional distinction between the contexts of discovery and justification is to insist on the normative character of epistemology. The point is not to dismiss from epistemology merely the genesis of ideas; into the context of discovery go also descriptions of evaluative practices and decisions. However ideas are created, scrutinized, and judged, it is only the approbation to which they are entitled, accorded or not, that allegedly matters to epistemology. The criticism, familiar since N.R. Hanson's Patterns of (...) Discovery, that philosophy ought not to ignore the genesis of ideas is ironically conservative. If what is not normative epistemology is to be ignored, then the distinction would have us ignore even the reception and appraisal of scientific ideas. (shrink)

Das Problem, unter welchen Bedingungen eine Hypothese oder Theorienmodifikation als methodologisch akzeptabel gilt, wird in der wissenschaftstheoretischen Tradition als die Frage des Ad-Hoc-Charakters von Hypothesen diskutiert. Das gleichartige Problem tritt aber auch in Lakatos' Methodologie wissenschaftlicher Forschungsprogramme auf, welche von methodologisch zulässigen Theorienänderungen die Vorhersage 'neuer Tatsachen' verlangt. Über diesen Begriff der neuen Tatsache und damit der Adäquatheitsbedingungen für wissenschaftliche Erklärungen hat sich eine weitgefächerte Debatte entsponnen. In diesem Papier wird der Versuch unternommen, die Forderung der unabhängigen Testbarkeit einer Hypothese, (...) welche im Rahmen der Diskussion des Ad-hoc-Charakters von Hypothesen eine wichtige Rolle spielt, auch für die Frage der Spezifizierung von 'neuen Tatsachen' fruchtbar zu machen. Ich argumentiere zugunsten der Bedingung, daß eine Hypothese als methodologisch akzeptabel gelten sollte, wenn sie zumindest zwei unabhängige Tatsachen erklärt. Ein derartiger Ansatz verlangt die Kennzeichnung dessen, was als 'eine Tatsache' zu gelten hat. Die Schwierigkeit einer derartigen Kennzeichnung ist ein notorisches Problem jedes Kriteriums, das auf unabhängige Testbarkeit zielt. Eine Klärung dieses Problems wird über das Konzept der empirischen Generalisierung versucht. Als 'eine Tatsache' im methodologischen Sinne gilt demnach ein gesetzmäßiger Zusammenhang zwischen zwei Meßgrößen. Dies erlaubt weiterführend eine Klärung des Problems, was methodologisch als 'ein Experiment' zu werten ist, d. h. was als Reproduktion desselben und was als andersartiges Experiment gelten soll. Mit Hilfe dieser Klärungen wird unter anderem der Ad-hoc-Charakter der Lorentzschen Kontraktionshypothese sowie das Problem der Gleich- oder Verschiedenartigkeit von Michelson-Morley- und Kennedy-Thorndike-Experiment untersucht. (shrink)