The Postlude, written for this edition, looks back at the predictions made more than twenty-five years ago and speculates about what the coming decades may hold ...

The purpose of this paper is to formulate first-order Peano arithmetic within the resources of relevant logic, and to demonstrate certain properties of the system thus formulated. Striking among these properties are the facts that it is trivial that relevant arithmetic is absolutely consistent, but classical first-order Peano arithmetic is straightforwardly contained in relevant arithmetic. Under, I shall show in particular that 0 = 1 is a non-theorem of relevant arithmetic; this, of course, is exactly the formula whose unprovability was (...) sought in the Hilbert program for proving arithmetic consistent. Under, I shall exhibit the requisite translation, drawing some Goedelian conclusions therefrom. Left open, however, is the critical problem whether Ackermann’s rule γ is admissible for theories of relevant arithmetic. The particular system of relevant Peano arithmetic featured in this paper shall be called R♯. Its logical base shall be the system R of relevant implication, taken in its first-order form RQ. Among other Peano arithmetics we shall consider here in particular the systems C♯, J♯, and RM3♯; these are based respectively on the classical logic C, the intuitionistic logic J, and the Sobocinski-Dunn semi-relevant logic RM3. And another feature of the paper will be the presentation of a system of natural deduction for R♯, along lines valid for first-order relevant theories in general. This formulation of R♯ makes it possible to construct relevantly valid arithmetical deductions in an easy and natural way; it is based on, but is in some respects more convenient than, the natural deduction formulations for relevant logics developed by Anderson and Belnap in Entailment. (shrink)

The thought that human embryos could command moral respect yet also be acceptably used in medical research has struck some as incoherent. Given some assumptions about why they deserve respect, however, the thought is not objectionable, indeed not even unusual.

This paper argues that modal realism has a problem with mathematical impossibilities. Due to the peculiar way it treats both propositions and mathematical objects, modal realism cannot distinguish the content of different mathematically impossible beliefs. While one might be happy to identify all logically impossible beliefs, there are many different mathematically impossible beliefs, none of which is a belief in a logical contradiction. The fact that it cannot distinguish these beliefs speaks against adopting modal realism.

According to Hans Kamp and Frank Vlach, the two-dimensional tense operators “now” and “then” are ineliminable in quantified tense logic. This is often adduced as an argument against tense logic, and in favor of an extensional account that makes use of explicit quantification over times. The aim of this paper is to defend tense logic against this attack. It shows that “now” and “then” are eliminable in quantified tense logic, provided we endow it with enough quantificational structure. The operators might (...) not be redundant in some other systems of tense logic, but this merely indicates a lack of quantificational resources and does not show any deep-seated inability of tense logic to express claims about time. The paper closes with a brief discussion of the modal analogue of this issue, which concerns the role of the actuality operator in quantified modal logic. (shrink)

Mechanistic explanations, according to one prominent account, are derived from objective explanations (Craver 2007, 2014 ). Mechanistic standards of explanation are in turn pulled from nature, and are thereby insulated from the values of investigators, since explanation is an objectively defined achievement grounded in the causal structure of the world (Craver 2014 ). This results in the closure of mechanism’s explanatory standards—it is insulated from the values, norms and goals of investigators. I raise two problems with this position. First, it (...) relies on several ontological claims which, while plausible, fail to guarantee the objectivity of mechanistic explanatory standards to the degree of certainty required. Second, Craver’s position itself introduces a value–laden explanatory standard—the 3M requirement (Kaplan & Craver 2011 )—which undermines the closure of explanatory standards. I show how in practice mechanistic explanation is in part guided by explanatory taste, shorthand for background contextual values that influence our standards of explanation. Mechanism often has a particular pragmatically-oriented taste for control, and gerrymanders explanatory standards in order to obtain it. I conclude by arguing that objectivity, rather than being obtained through the right set of explanatory standards, is better thought of as the result of processes of intersubjective criticism, which renders visible the contextual values of communities of investigators and allows them to be controlled for (Longino 1990 ). (shrink)

Epistemic entrenchment, as presented by Gärdenfors and Makinson (1988) and Gärdenfors (1988), is a formalisation of the intuition that, when forced to choose between two beliefs, an agent will giveup the less entrenched one. While their formalisation satisfactorilycaptures the intuitive notion of the entrenchment of beliefs in a number ofaspects, the requirement that all wffs be comparable has drawn criticismfrom various quarters. We define a set of refined versions of theirentrenchment orderings that are not subject to the same criticism, andinvestigate (...) the relationship between the refined entrenched orderings,the entrenchment orderings of Gärdenfors and Makinson, and AGM theorycontraction (Alchourrón et al., 1985). To conclude, we compare refinedentrenchment with two related approaches to epistemic entrenchment. (shrink)

Psychological essentialism is a folk theory characterized by the belief that a causal internal essence or force gives rise to the common outward behaviors or attributes of a category's members. In two studies, we investigated whether 4- to 7-year-old children evidenced essentialist reasoning about heart transplants by asking them to predict whether trading hearts with an individual would cause them to take on the donor's attributes. Control conditions asked children to consider the effects of trading money with an individual. Results (...) indicated that children reasoned according to essentialism, predicting more transfer of attributes in the transplant condition versus the non-bodily money control. Children also endorsed essentialist transfer of attributes even when they did not believe that a transplant would change the recipient's category membership. This finding runs counter to predictions from a strong interpretation of the “minimalist” position, an alternative to essentialism. (shrink)

In South Africa, ideas around fatherhood, parenthood and family life are greatly shifting as people find themselves caught up between traditional and contemporary understandings of fatherhood and motherhood. Even though more than 70% of young South Africans stated in a national survey that parenthood is one of the top four defining features of adulthood, father absence is on the increase. Some in-depth literature study was conducted regarding South African research on fatherhood and father absence, and the role of both Christian (...) churches and secular organisations in addressing some of these challenges brought on by rapidly growing figures of father absence. The article concludes with some suggestions on the development of a new paradigm in understanding fatherhood in South Africa, with special reference to the role of Christian churches in assisting men to construct a narrative around fatherhood, which will lead to satisfying relationships with their children, their partners and especially with God. (shrink)

The author uses an intersectionality framework to examine how lesbian, gay, bisexual, and transgender people evaluate the severity of their violent experiences. Previous research focusing on the severity of anti-LGBT violence has given relatively little attention to race, class, and gender as systems of power. In contrast, results from this study, based on 47 semi-structured, in-depth interviews, reveal that Black and Latino/latina respondents often perceived anti-queer violence as implying that they had negatively represented their racial communities, whereas white respondents typically (...) overlooked the racialized implications of their violent experiences. Furthermore, while lesbians of color emphasized their autonomy and self-sufficiency to challenge this discourse, Black and Latino gay men underscored their emotional and physical strength to undermine perceptions that they were weak for identifying as gay. Results also indicate that LGBT people experience forms of anti-queer violence in different ways depending on their social position, as Black lesbians faced discourse that neither white lesbians nor Black gay men were likely to confront. Thus, these findings suggest that topics primarily associated with homophobia should be examined through an intersectional lens. (shrink)

Intelligent agents are often faced with the problem of trying to combine possibly conflicting pieces of information obtained from different sources into a coherent view of the world. We propose a framework for the modelling of such combination operations with roots in the work of Spohn [Spo88, Spo91]. We construct a number of combination operations and we measure them against various properties that such operations ought to satisfy. We conclude by discussing the connection between combination operations and the use of (...) infobases [Mey99, MLH00]. (shrink)

After having defined the KARO logic for specifying intelligent agents in earlier work we now turn to the question how to realise agents specified in the KARO framework. To this end we look at agent programming languages that we have defined, and investigate how programs in these languages can be linked to the KARO logic.

Research suggests that institutions affect the levels of corruption in a country. We take these arguments a step further and examine whether it is the presence of inclusive institutions and/or the credible and consistent implementation of institutions that matter, as regards corruption. We use a novel approach to theoretically conceptualise and empirically operationalise institutions along two analytically distinct dimensions: the nature of the institutions (the de jure dimension), and the extent to which they are credibly and consistently implemented over time (...) (the de facto dimension), using a panel dataset for 148 countries covering 2012 to 2018. We find that formal institutions are most effective in reducing corruption when the rules are credibly and consistently implemented. Furthermore, this effect appears to operate differently at different levels of national income. The nature of the formal institutions appears important across income levels, but particularly so at the upper middle income level, while the credible and consistent implementation of these institutions is primarily influential at upper middle income levels. We explain why this may be the case and elaborate on the policy implications. (shrink)

David Bostock has produced a translation that admirably fulfills the Clarendon Aristotle Series’ goal of making Aristotle’s texts accessible to the Greekless philosophical reader. It is accurate without being overly literal and is probably the best available in English. Despite Bostock’s inelegant rendering of to ti en einai as "a what-being-is", and to ti esti as "a what-it-is", the translation is, on the whole, highly readable and brings out perspicuously the structure of Aristotle’s arguments.

With the aim of studying foundations for self-other relations and understanding, we conducted an experimental investigation of a specific aspect of imitation in children with autism: the propensity to copy self-other orientation. We hypothesised that children with autism would show limitations inidentifying withthe stance of another person. We tested 16 children with autism and 16 non-autistic children with learning difficulties, matched on both chronological and verbal mental age, for their propensity to imitate the self- or other-orientated aspects of another person’s (...) actions. All participants were attentive to the demonstrator and copied her actions, but the children with autism were significantly less likely to imitate those aspects of her actions that involved movement in relation to her own vis-à-vis the child’s body. There were a number of children with autism who copied the identical geometric orientation of objects acted-upon. These results suggest that children with autism have a diminished propensity to identify with other people, and point to the importance of this mechanism for shaping self-other relations and flexible thinking. (shrink)

With the aim of studying foundations for self-other relations and understanding, we conducted an experimental investigation of a specific aspect of imitation in children with autism: the propensity to copy self-other orientation. We hypothesised that children with autism would show limitations inidentifying withthe stance of another person. We tested 16 children with autism and 16 non-autistic children with learning difficulties, matched on both chronological and verbal mental age, for their propensity to imitate the self- or other-orientated aspects of another person’s (...) actions. All participants were attentive to the demonstrator and copied her actions, but the children with autism were significantly less likely to imitate those aspects of her actions that involved movement in relation to her own vis-à-vis the child’s body. There were a number of children with autism who copied the identical geometric orientation of objects acted-upon. These results suggest that children with autism have a diminished propensity to identify with other people, and point to the importance of this mechanism for shaping self-other relations and flexible thinking. (shrink)

Preliminary Remarks: Before entering into the subject matter of the paper, it may be useful to present American readers with a sketchy outline of present-day European philosophy of science, as it appeared to me at the International Congress of Philosophy of Science, held in Paris at the Sorbonne on October 15–22, 1949. The sections of which I can give a first hand impression and which are of particular interest for our subject, are those of physical science and of probability.