Brian Porter

Philosophers have argued that stakes affect knowledge: a given amount of evidence may suffice for knowledge if the stakes are low, but not if the stakes are high. By contrast, empirical work on the influence of stakes on ordinary knowledge ascriptions has been divided along methodological lines: “evidence‐fixed” prompts rarely find stakes effects, while “evidence‐seeking” prompts consistently find them. We present a cross‐cultural study using both evidence‐fixed and evidence‐seeking prompts with a diverse sample of 17 populations in 11 countries, speaking 14 languages. Our study is the first to use an evidence‐seeking prompt cross‐culturally, and includes several previously untested populations (including indigenous populations). Across cultures, we do not find evidence of a stakes effect with our evidence‐fixed prompt, but do with our evidence‐seeking prompt. We argue that the divergent results reveal a tension within folk epistemology: people's beliefs about when it is appropriate to ascribe knowledge differ significantly from their actual practice in ascribing knowledge.

Devitt and Porter tested the hypothesis that a biological term referring to a taxon of scientific but little practical interest, ‘Rio de Janeiro Myrtle’, would be covered by a Causal‐Historical Theory of reference, as Saul Kripke suggested, but that one referring to a kind of significant practical interest, ‘rice’, would not. ‘Rice’ would be covered by a Hybrid Theory, part‐causal, part‐descriptive, and so Kripke would be only half‐right about ‘rice’. Devitt and Porter concluded that their experiments confirmed this hypothesis. The present paper raises concerns that those experiments may have improperly biased participants against the Description Theory. The paper presents the results of follow‐up experiments on ‘Rio de Janeiro Myrtle’ and ‘rice’ designed to remove those concerns. The paper concludes that Kripke was indeed right about ‘scientific’ biological kind terms while being only half‐right about ‘practical’ biological kind terms.

The article reports experiments testing the theory of reference for implement terms, using “fax machine” and “abacus” as examples. We found strong evidence against the description theory that the reference of these terms is determined by the descriptions that participants associate with them. This supports the causal theory of reference borrowing for these terms. We emphasize that our findings do not support a causal theory of the initial reference fixing by the “experts” who introduce an implement term. Indeed, we think it highly plausible that reference is initially fixed by a description of the implement's function and defining physical characteristics.

Recent experimental work on “natural” kind terms has shown evidence of both descriptive and nondescriptive reference determination. This has led some to propose ambiguity or hybrid theories, as opposed to traditional description and causal‐historical theories of reference. Many of those experiments tested theories against referential intuitions. We reject this method, urging that reference should be tested against usage, preferably by elicited production. Our tests of the usage of a biological kind term confirm that there are indeed both descriptive and causal‐historical elements to the reference determination of some natural kind terms. We argue that to accommodate our results and earlier ones, we should abandon the common assumption that any one theory of reference fits all natural kind terms. Rather, it is likely that some terms are descriptive, some causal‐historical, some ambiguous, and some hybrid. This substantive conclusion is accompanied by a methodological one. Our experiments, like some earlier ones, found participants contradicting both each other and themselves. We argue that these contradictions indicate a lack of linguistic competence with the term. We conclude that these experiments have been faulty, because they test terms that are novel to participants and/or use fantastical vignettes. We provide some suggestions for future research.

In a recent paper, Barrio, Pailos and Szmuc (BPS) show that there are logics that have exactly the validities of classical logic up to arbitrarily high levels of inference. They suggest that a logic therefore must be identified by its valid inferences at every inferential level. However, Scambler shows that there are logics with all the validities of classical logic at every inferential level, but with no antivalidities at any inferential level. Scambler concludes that in order to identify a logic, we at least need to look at the validities and the antivalidities of every inferential level. In this paper, I argue that this is still not enough to identify a logic. I apply BPS’s techniques in a super/sub-valuationist setting to construct a logic that has exactly the validities and antivalidities of classical logic at every inferential level. I argue that the resulting logic is nevertheless distinct from classical logic.

Teleosemantics explains mental representation in terms of etiological history: a mental state’s representational contents are the result of natural selection, or some other selection process. Critics have argued that the “swampman” thought experiment poses a counterexample to teleosemantics. In several recent papers, Papineau has argued that a merely possible swampman cannot serve as a counterexample to teleosemantics, but has acknowledged that actual swampmen would pose a problem for teleosemantics. In this paper, I argue that there are real-world cases of swampman-like representation, in the form of functional tetrachromacy. People with functional tetrachromacy are born with four types of cones in each eye, rather than the usual three, and as a result can represent a wider variety of colors than the average person. I argue that the functional tetrachromat’s additional color representations are not the result of a selection process. Functional tetrachromacy is therefore a real-world case of mental representation without an etiological history, and therefore poses a genuine counterexample to teleosemantics.

Experiments have led some philosophers to conclude that the reference determination of natural kind terms is neither simply descriptive nor simply causal-historical. Various theories have been aired to account for this, including ambiguity, hybrid, and different-idiolects theories. Devitt and Porter (2021) hypothesized that some terms are covered by one theory, some another, with a place for all the proposed theories. The present paper tests hypotheses that the term ‘Rio de Janeiro Myrtle’ is simply causal-historical but the term ‘rice’ is hybrid. For, whereas the former term is of scientific but little practical interest, the latter is not: rice is a significant part of the human diet. So, we predicted there would be two factors to the reference determination of ‘rice’: a superficial-descriptive one and a deep-causal one. Our experiments confirmed these hypotheses using the methods of elicited production and truth value judgments. We take our results to support the hybrid Theory of ‘rice’ rather than the ambiguity or different-idiolects theory. We were not testing ‘myrtle’ but, surprisingly, our results implied that ‘myrtle’ was partly descriptive and so like ‘rice’ but not ‘Rio de Janeiro Myrtle’. A follow-up experiment confirmed these puzzling results. More investigation is needed.