Does the Dome Defeat the Material Theory of Induction?

According to John D. Norton's Material Theory of Induction, all inductive inferences are justified by local facts, rather than their formal features or some grand principles of nature's uniformity. Recently, Richard Dawid (Found Phys 45(9):1101–1109, 2015) has offered a challenge to this theory: in an adaptation of Norton's own celebrated "Dome" thought experiment, it seems that there are certain inductions that are intuitively reasonable, but which do not have any local facts that could serve to justify them in accordance with Norton's requirements. Dawid's suggestion is that “raw induction” might have a limited but important role for such inferences. I argue that the Material Theory can accommodate such inductions, because there are local facts concerning the combinatoric features of the induction’s target populations that can licence the inferences in an analogous way to existing examples of material induction. Since my arguments are largely independent of the details of the Dome, Norton's theory emerges as surprisingly robust against criticisms of excessive narrowness.

Two approaches to natural kinds

Philosophical treatments of natural kinds are embedded in two distinct projects. I call these the philosophy of science approach and the philosophy of language approach. Each is characterized by its own set of philosophical questions, concerns, and assumptions. The kinds studied in the philosophy of science approach are projectible categories that can ground inductive inferences and scientific explanation. The kinds studied in the philosophy of language approach are the referential objects of a special linguistic category—natural kind terms—thought to refer directly. Philosophers may hope for a unified account addresses both sets of concerns. This paper argues that this cannot be done successfully. No single account can satisfy both the semantic objectives of the philosophy of language approach and the explanatory projects of the philosophy of science approach. After analyzing where the tensions arise, I make recommendations about assumptions and projects that are best abandoned, those that should be retained, and those that should go their separate ways. I also recommend adopting the disambiguating terminology of “scientific kinds” and “natural kinds” for the different notions of kinds developed in these different approaches.

Children's use of generic labels, discreteness, and stability to form a novel category

Children hold rich essentialist beliefs about natural and social categories, representing them as discrete (mutually exclusive with sharp boundaries) and stable (with membership remaining constant over an individual’s lifespan). Children use essential categories to make inductive inferences about individuals. How do children determine what categories to consider essential and to use as an inductive base? Although much research has demonstrated children’s use of labels to form categories, here we explore whether children might also use the observed discreteness or stability of a trait to form categories based on that trait. In the present study, we taught children about novel creatures and provided them with a cue (discreteness, stability, labels, or no cue) to form texture categories rather than shape or color categories. Experiment 1 found that children (4–6 years, n = 140) used labels but not discreteness or stability cues to form texture categories more often than at baseline. Experiment 2 (5–6 years, n = 152) found that children who later recognized the stability and discreteness cues used them to form categories more often than those who did not later recognize the cues, but were still overall less likely to use these cues than to use labels cues. Results underscore the unique importance of labels as a cue for category formation and suggest that children do not readily rely on the stability and discreteness of a trait to form animate categories despite readily inferring that such categories are stable and discrete. Implications for natural and social category representations are discussed.

Young Children’s Inductive Inferences Within Animals Are Affected by Whether Animals Are Presented Anthropomorphically in Films

Children are exposed to anthropomorphized animals in a variety of contexts. The literature that analyzes this phenomenon suggests that exposure to anthropomorphic media may strengthen children’s anthropocentric representation of animals. There is an as yet unexplored difference between anthropomorphized and realistic depictions of multiple animal species presented simultaneously in films. The anthropomorphized animals all behave like humans, so they are more behaviorally similar to one another than animals depicted realistically. We asked whether witnessing multiple species depicted anthropomorphically or realistically influences the way 5-year-old children perceive internal commonalities among animals. One group of children (n = 37) watched a cartoon presenting multiple species of anthropomorphized animals, the other group (n = 38) watched a nature documentary that also presented multiple species. Both groups extended a novel internal feature from an animal to a variety of items including diverse animal species. Children watching a cartoon made significantly stronger projections to non-human animals than children watching the documentary. Children’s projections to humans and inanimate objects did not differ between the groups and were uniformly low. One of the possible explanations of the results is in terms of children’s essentialist expectation that behavior is caused by internal properties.

What’s my age again? Age categories as interactive kinds

This paper addresses a philosophical problem concerning the ontological status of age classification. For various purposes, people are commonly classified into categories such as “young adulthood”, “middle adulthood”, and “older adulthood”, which are defined chronologically. These age categories prima facie seem to qualify as natural kinds under a homeostatic property cluster account of natural kindhood, insofar as they capture certain biological, psychological, and social properties of people that tend to cluster together due to causal processes. However, this is challenged by the observation that age categories are historically unstable. The properties that age categories are supposed to capture are affected by healthcare and cultural developments, such that people are staying biologically, psychologically, and socially young for longer. Furthermore, the act of classifying people into age categories can bring about changes in their behaviors, which in turn alter the biological, psychological, and social properties that the categories are supposed to capture. Accordingly, I propose that age categories are best understood as interactive kinds that are influenced in dynamic ways by looping effects. I consider some implications of these looping effects for our classificatory practices concerning age, including how different disciplines may need to review the ways they define and use age categories in their inductive inferences.

Hempel’s Raven Revisited

The paper takes a novel approach to a classic problem—Hempel’s Raven Paradox. A standard approach to it supposes the solution to consist in bringing our inductive logic into “reflective equilibrium” with our intuitive judgements about which inductive inferences we should license. This approach leaves the intuitions as a kind of black box and takes it on faith that, whatever the structure of the intuitions inside that box might be, it is one for which we can construct an isomorphic formal edifice, a system of inductive logic. By popping open the box we can see whether that faith is misplaced. I aim, therefore, to characterize our pre-theoretical, intuitive understanding of generalizations like “ravens are black” and argue that, intuitively, we take them to mean, for instance: “ravens are black by some indeterminate yet characteristic means.” I motivate and explicate this formulation and bring it to bear on Hempel’s Problem.

The Material Theory of Induction at the Frontiers of Science

According to John D. Norton's Material Theory of Induction, all reasonable inductive inferences are justified in virtue of background knowledge about local uniformities in nature. These local uniformities indicate that our samples are likely to be representative of our target population in our inductions. However, a variety of critics have noted that there are many circumstances in which induction seems to be reasonable, yet such background knowledge is apparently absent. I call such an absence of circumstances ‘the frontiers of science', where background scientific theories do not provide information about such local uniformities. I argue that the Material Theory of Induction can be reconciled with our intuitions in favour of these inductions. I adapt an attempted justification of induction in general, the Combinatoric Justification of Induction, into a more modest rationalisation at the less foundational level that the critics discuss. Subject to a number of conditions, we can extrapolate from large samples using our knowledge of facts about the minimum proportions of representative subsets of finite sets. I also discuss some of Norton's own criticisms of his theory and argue that he is overly pessimistic. I conclude that Norton's theory at least performs well at the frontiers of science.