A textbook on modal logic, intended for readers already acquainted with the elements of formal logic, containing nearly 500 exercises. Brian F. Chellas provides a systematic introduction to the principal ideas and results in contemporary treatments of modality, including theorems on completeness and decidability. Illustrative chapters focus on deontic logic and conditionality. Modality is a rapidly expanding branch of logic, and familiarity with the subject is now regarded as a necessary part of every philosopher's technical equipment. Chellas (...) here offers an up-to-date and reliable guide essential for the student. (shrink)

We define prenormal modal logics and show that S1, S1, S0.9, and S0.9 are Lewis versions of certain prenormal logics, determination and decidability for which are immediate. At the end we characterize Cresswell logics and ponder C. I. Lewis's idea of strict implication in S1.

Recent theories of agency (sees to it that) of Nuel Belnap and Michael Perloff are examined, particularly in the context of an early proposal of the author.

Having gained some idea of what MacIntosh logics there are, we conclude this paper with a remark about the totality of them. Let theterritory of a rule or condition be the class of all modal logics that have the rule or satisfy the condition. What is MacIntosh territory, the class of all normal logics with the MacIntosh rule, like? What is its structure?

In his paper Leblanc seeks to supplant traditional forms of semantic theory with truth-value analyses. I have tried, here, to extend the scope, if not the limits, of his results. But now, in closing, I wish to register some reservations about his notion of relevance.Leblanc eschews the customary semantic analysis of intensional languages — the so-called ‘possible worlds’ semantics — as making ‘metaphysical virtue out of logical necessity’. And so he would replace such accounts with ‘truth-value’ analyses. But, alas, these (...) theories are seen to have only limited application. Either all the atoms of a language must be evaluated by the functions in W in a truth-value ℋ 〈W, α, R〉, or the functions must be indexed. Because I share Leblanc's opinion that it ought to be that only the atoms of a theory are linguistically pertinent to it, I opt for the second alternative. Here, of course, things work out all right. But, as Leblanc notes, indexing the functions is equivalent to doing semantics in the usual way. In either case, new parameters are required for the evaluation of theories. So more than just the truth-values of a theory's atoms is relevant.My concern is with natural languages. It has long been recognized — though only more recently well articulated4 — that an adequate semantic analysis of such languages, with their indexical and intensional features, must relativize the notion of truth to various indices, viz., aspects of the contexts of utterance of sentences. It is clear that the truth-value of ‘If your feet hurt, then it may rain tomorrow’ depends on more than just the truth-values of its atoms: the speaker, hearer, place, and time of utterance of the sentence are at least to be included among the extra-linguistic features required for an evaluation of the sentence. Such indices thus provide various realizations of the notion of a possible world, and they are all relevant. (shrink)

We can perceive not only low-level features of events such as color and motion, but also seemingly higher-level properties such as causality. A prototypical example of causal perception is the ”launching effect’: one object moves toward a stationary second object until they are adjacent, at which point A stops and B starts moving in the same direction. Beyond these motions themselves --- and regardless of any higher-level beliefs --- this display induces a vivid visual impression of causality, wherein A is (...) seen to cause B’s motion. Do such percepts reflect a unitary category of visual processing, or might there be multiple distinct forms of causal perception? While launching is often simply equated with causal perception, researchers have sometimes described other phenomena such as ”triggering’ and ”entraining’. We used psychophysical methods to determine whether these labels really carve visual processing at its joints, and how putatively different forms of causal perception relate to each other. Previous research demonstrated retinotopically specific adaptation to causality: exposure to causal launching makes subsequent ambiguous events in that same location more likely to be seen as non-causal ”passing’. Here, after replicating this effect, we show that exposure to triggering also yields retinotopically specific adaptation for subsequent ambiguous launching displays, but that exposure to entraining does not. Collectively, these results reveal that visual processing distinguishes some types of causal interactions. (shrink)

Decaying wood, while an abundant and stable resource, presents considerable nutritional challenges due to its structural rigidity, chemical recalcitrance, and low nitrogen content. Despite these challenges, certain insect lineages have successfully evolved saproxylophagy (consuming and deriving sustenance from decaying wood), impacting nutrient recycling in ecosystems and carbon sequestration dynamics. This study explores the uneven phylogenetic distribution of saproxylophagy across insects and delves into the evolutionary origins of this trait in disparate insect orders. Employing a comprehensive analysis of gut microbiome data, (...) from both saproxylophagous insects and their non‐saproxylophagous relatives, including new data from unexplored wood‐feeding insects, this Hypothesis paper discusses the broader phylogenetic context and potential adaptations necessary for this dietary specialization. The study proposes the “Detritivore‐First Hypothesis,” suggesting an evolutionary pathway to saproxylophagy through detritivory, and highlights the critical role of symbiotic gut microbiomes in the digestion of decaying wood. (shrink)

After yeast cells commit to the cell cycle in a process called START, genes required for DNA synthesis are expressed in late G1. Periodicity is mediated by a hexameric sequence, known as a MCB element, present in all DNA synthesis gene promoters. A complex that specifically binds MCBs has been identified. One polypeptide in the MCB complex is Swi6, a transcription factor that together with Swi4 also binds G1 cyclin promoters and participates in a positive feedback loop at START. The (...) finding that Swi6 is directly involved in both START and DNA synthesis gene control suggest a model in which Swi6, activated through its participation in START, serves as the central transcription factor in coordinating late G1 gene expression. The mechanism may be conserved in all eukaryotic cells. (shrink)

In theTractatus, Wittgenstein advocates two major notational innovations in logic. First, identity is to be expressed by identity of the sign only, not by a sign for identity. Secondly, only one logical operator, called “N” by Wittgenstein, should be employed in the construction of compound formulas. We show that, despite claims to the contrary in the literature, both of these proposals can be realized, severally and jointly, in expressively complete systems of first-order logic. Building on early work of Hintikka’s, we (...) identify three ways in which the first notational convention can be implemented, show that two of these are compatible with the text of theTractatus, and argue on systematic and historical grounds, adducing posthumous work of Ramsey’s, for one of these as Wittgenstein’s envisaged method. With respect to the second Tractarian proposal, we discuss how Wittgenstein distinguished between general and non-general propositions and argue that, claims to the contrary notwithstanding, an expressively adequate N-operator notation is implicit in theTractatuswhen taken in its intellectual environment. We finally introduce a variety of sound and complete tableau calculi for first-order logics formulated in a Wittgensteinian notation. The first of these is based on the contemporary notion of logical truth as truth in all structures. The others take into account the Tractarian notion of logical truth as truth in all structures over one fixed universe of objects. Here the appropriate tableau rules depend on whether this universe is infinite or finite in size, and in the latter case on its exact finite cardinality.As it is obviously easy to express how propositions can be constructed by means of this operation and how propositions are not to be constructed by means of it, this must be capable of exact expression.5.503. (shrink)

This book contains seminal discussions of central issues in the philosophy of language, mathematics, mind, religion and time. Is common language conceptually prior to idiolectics? What is a theory of meaning? Does constructivism provide a satisfactory account of mathematics? What are indefinitely extensible concepts? Can we change the past? These are only some of the very important questions addressed here. Both the papers written by the contributors and Dummett's replies provide a great wealth of stimulating ideas for those who currently (...) do research in the respective areas touched upon without making the reading exceedingly tedious. This feature, common to most of the papers in this book, makes it possible to use the material presented in undergraduate courses at university level. (shrink)

Karl Rahner’s theory of fundamental option has been criticized in recent years due to a perceived discontinuity between categorical actions in history and their transcendental implications. Jean Porter, for example, argues that such a discontinuity undermines any usefulness of the theory for the moral life because it is unable to generate a substantive account of the life of virtue. This essay disputes such claims, arguing that Rahner’s reluctance to definitively connect particular actions with a positive or negative fundamental option is (...) simply in keeping with the Roman Catholic tradition of being tentative with regard to subjective judgments about the relationship between particular actions and the state of one’s soul. Further, it is argued that an examination of Rahner’s understanding of the unity of love of God and love of neighbor will serve to generate paradigmatic behaviors which are potential “sites” for a fundamental option. In this regard, the essay focuses on Rahner’s discussions of conscience and Ignatian discernment as well as on the relationship of fundamental option to “dying with Christ” or Christian witness. (shrink)

When men and women cannot attain idealized gendered forms of economic provision and dependence, how do they make sense of this perceived failure? In this article, we posit that poor health narratives serve as a gendered tool to make sense of inadequate livelihoods, even when that inadequacy is attributable to structural conditions. We draw on survey and life-history interview data from middle-aged and older rural South Africans. The survey data show that even after adjusting for biometrically measured health differences, working-age (...) men report poorer health when they are unemployed, and women and pension-age men report poorer health when they live without household earners. Life-history interviews show parallel patterns: When their economic circumstance is not troubled, individuals regularly minimize health concerns; conversely, when they have a troubled livelihood, individuals draw on poor health to explain it. When women and men cannot perform idealized gendered practices in the family, poor health becomes a tool to reduce the resulting cognitive dissonance. Poor health narratives recast perceived gender failures to an individualized, biological explanation. Our study illustrates how the epidemiological context can be a resource that forestalls a redefinition of gender norms when the gender order is in crisis. (shrink)

This paper proposes the ‘AGENCY model’ of conscious state attribution, according to which an entity's displaying certain relatively simple features (e.g. eyes, distinctive motions, interactive behavior) automatically triggers a disposition to attribute conscious states to that entity. To test the model's predictions, participants completed a speeded object/attribution task, in which they responded positively or negatively to attributions of mental properties (including conscious and non-conscious states) to different sorts of entities (insects, plants, artifacts, etc.). As predicted, participants responded positively to conscious (...) state attributions only for those entities that typically display the simple features identified in the AGENCY model (eyes, distinctive motion, interaction) and took longer to deny conscious states to those entities. (shrink)