The so-called problem of irrelevant conjunction has been seen as a serious challenge for theories of confirmation. It involves the consequences of conjoining irrelevant statements to a hypothesis that is confirmed by some piece of evidence. Following Hawthorne and Fitelson, we reconstruct the problem with reference to Bayesian confirmation theory. Then we extend it to the case of conjoining irrelevant statements to a hypothesis that is disconfirmed by some piece of evidence. As a consequence, we obtain and formally present a novel and more troublesome problem of irrelevant conjunction. We conclude by indicating a possible solution based on a measure-sensitive approach and by critically discussing a major alternative way to address the problem.

Critics of the ideal of value-free science often assume that they must reject the distinction between epistemic and nonepistemic values. I argue that this assumption is mistaken and that the distinction can be used to clarify and defend the argument from inductive risk, which challenges the value-free ideal. I develop the idea that the characteristic feature of epistemic values is that they promote, either intrinsically or extrinsically, the attainment of truths. This proposal is shown to answer common objections to the distinction and provide a principled basis for separating legitimate from illegitimate influences of nonepistemic values in scientific inference.

I argue that a certain type of naturalist should not accept a prominent version of the no-miracles argument (NMA). First, scientists (usually) do not accept explanations whose explanans-statements neither generate novel predictions nor unify apparently disparate established claims. Second, scientific realism (as it appears in the NMA) is an explanans that makes no new predictions and fails to unify disparate established claims. Third, many proponents of the NMA explicitly adopt a naturalism that forbids philosophy of science from using any methods not employed by science itself. Therefore, such naturalistic philosophers of science should not accept the version of scientific realism that appears in the NMA.

A common argument against explanatory reductionism is that higher-level explanations are sometimes or always preferable because they are more general than reductive explanations. Here I challenge two basic assumptions that are needed for that argument to succeed. It cannot be assumed that higher-level explanations are more general than their lower-level alternatives or that higher-level explanations are general in the right way to be explanatory. I suggest a novel form of pluralism regarding levels of explanation, according to which explanations at different levels are preferable in different circumstances because they offer different types of generality, which are appropriate in different circumstances of explanation.

Over the last 2,300 years or so, many philosophers have believed that species are individuated by essences that are at least in part intrinsic. Psychologists tell us most folks also believe this view. But most philosophers of biology have abandoned the view, in light of evolutionary conceptions of species. In defiance, Michael Devitt has attempted in this journal to resurrect a version of the view, which he calls Intrinsic Biological Essentialism. I show that his arguments for the resurrection fail, and I identify challenges that face anyone wishing to defend Intrinsic Biological Essentialism.

Philosophy of scientific practice aims to critically evaluate as well as describe scientific inquiry. Epistemic norms are required for such evaluation. Social constructivism is widely thought to oppose this critical project. I argue, however, that one variety of social constructivism, focused on epistemic justification, can be a basis for critical epistemology of scientific practice, while normative accounts that reject this variety of social constructivism (SCj) cannot. Abstract, idealized epistemic norms cannot ground effective critique of our practices. I propose a new approach, placing SCj within a general framework of social action theory. This framework can be used to explicate epistemic norms implicit in our scientific practices.

It is argued that recent discussion of the principle of the identity of indiscernibles (PII) and quantum mechanics has lost sight of the broader philosophical motivation and significance of PII and that the ‘received view' of the status of PII in the light of quantum mechanics survives recent criticisms of it by Muller, Saunders, and Seevinck.