A class of simpler logical matrices for the variable-sharing property

In our paper “A general characterization of the variable-sharing property by means of logical matrices”, a general class of so-called “Relevant logical matrices”, RMLs, is defined. The aim of this paper is to define a class of simpler Relevant logical matrices RMLs′serving the same purpose that RMLs, to wit: any logic verified by an RML′has the variable-sharing property and related properties predicable of the logic of entailment E and of the logic of relevance R

A Note on the Relevance of Semilattice Relevance Logic

A propositional logic has the variable sharing property if φ →’ ψ is a theorem only if φ and ψ share some propositional variable(s). In this note, I prove that positive semilattice relevance logic (R+u) and its extension with an involution negation (R¬u) have the variable sharing property (as these systems are not subsystems of R, these results are not automatically entailed by the fact that R satisfies the variable sharing property). Typical proofs of the variable sharing property rely on ad hoc, if clever, matrices. However, in this note, I exploit the properties of rather more intuitive arithmetical structures to establish the variable sharing property for the systems discussed

A Note on the Relevance of Semilattice Relevance Logic

A propositional logic has the variable sharing property if φ →’ ψ is a theorem only if φ and ψ share some propositional variable(s). In this note, I prove that positive semilattice relevance logic (R+u) and its extension with an involution negation (R¬u) have the variable sharing property (as these systems are not subsystems of R, these results are not automatically entailed by the fact that R satisfies the variable sharing property). Typical proofs of the variable sharing property rely on ad hoc, if clever, matrices. However, in this note, I exploit the properties of rather more intuitive arithmetical structures to establish the variable sharing property for the systems discussed

Goal-directed proof theory

This report is the draft of a book about goal directed proof theoretical formulations of non-classical logics. It evolved from a response to the existence of two camps in the applied logic (computer science/artificial intelligence) community. There are those members who believe that the new non-classical logics are the most important ones for applications and that classical logic itself is now no longer the main workhorse of applied logic, and there are those who maintain that classical logic is the only logic worth considering and that within classical logic the Horn clause fragment is the most important one. The book presents a uniform Prolog-like formulation of the landscape of classical and non-classical logics, done in such away that the distinctions and movements from one logic to another seem simple and natural; and within it classical logic becomes just one among many. This should please the non-classical logic camp. It will also please the classical logic camp since the goal directed formulation makes it all look like an algorithmic extension of Logic Programming. The approach also seems to provide very good compuational complexity bounds across its landscape

Metascientific views: Challenge and opportunity for philosophy of biology in practice

In this paper I take evolutionary biology as an example to reflect on the role of philosophy and on the transformations that philosophy is constantly stimulated to do in its own approach when dealing with science. I consider that some intellectual movements within evolutionary biology (more specifically, the various calls for 'synthesis') express metascientific views, i.e., claims about 'what it is to do research' in evolutionary biology at different times. In the construction of metascientific views I see a fundamental role to be played by philosophy, and, at the same time, a need to complement the philosophical methods with many more methods coming from other sciences. What leads philosophy out of itself is its own attention to scientific practice. My humble methodological suggestions are, at this stage, only meant to help us imagine metascientific views that are built with a more scientific, interdisciplinary approach, in order to attenuate partiality, subjectivity and impressionism in describing the scientific community. And yet, we should not be naïve and imbued with the myth of 'datadriven' research, especially in this field: other complex issues about metascientific views call for a serious, constant philosophical reflection on scientific practice

Coleridge, Isherwood and Hindu Light

This essay explores light, as conceived in Hinduism, as an intellectual tool used to mediate the contrary impulses of body and soul. Samuel Taylor Coleridge and Christopher Isherwood addressed this philosophical quandary by reference to the light-based cosmology of Bhagavad Gita. They did so by opposite means: Coleridge's search for the Hindu light was primarily based on reading, while Isherwood adopted self-cultivation practices. In ‘Dejection: An Ode’, the Indian idea of light allows Coleridge to imagine the resolution of his love for Sara Hutchinson. By contrast, Isherwood devoted himself to the Hindu light physically by involvement with a meditation centre, as documented in his memoir, My Guru and His Disciple. Like Coleridge, Isherwood suffered reputational damage for his metaphysical interests, and was deemed an unfulfilled talent. Yet W. H. Auden's ambivalent responses to Isherwood indicate his belief that the western literary canon might be enriched as a result of such esoteric experience

Some Locally Tabular Logics with Contraction and Mingle

Anderson and Belnap’s implicational system RMO can be extended conservatively by the usual axioms for fusion and for the Ackermann truth constant t. The resulting system RMO is algebraized by the quasivariety IP of all idempotent commutative residuated po-monoids. Thus, the axiomatic extensions of RMO are in one-to-one correspondence with the relative subvarieties of IP. An algebra in IP is called semiconic if it decomposes subdirectly (in IP) into algebras where the identity element t is order-comparable with all other elements. The semiconic algebras in IP are locally finite. It is proved here that a relative subvariety of IP consists of semiconic algebras if and only if it satisfies x ≈ (x → t) → x. It follows that if an axiomatic extension of RMO has ((p → t) → p) → p among its theorems then it is locally tabular. In particular, such an extension is strongly decidable, provided that it is finitely axiomatized

'If I have only two children and they die. who will take care of me?' : a qualitative study exploring knowledge, attitudes and practices about family planning among Mozambican female and male adults

Background: By focusing upon family planning counselling services, the Mozambican government has significantly enhanced the general health of female and male clients. However, little is known about the experiences of family planning by female and male adults. This article focuses on knowledge, attitudes and practices regarding contraceptive methods and fertility intentions. Methods: An in-depth qualitative study of female and male clients was conducted in two settings in Maputo province - Ndlavela and Boane. A total of sixteen in-depth interviews, four informal conversations, and observations were equally divided between both study sites. The analysis followed a constructionist approach. Three steps were considered in the analysis: examining commonalities, differences and relationships. Results: Although there was a high level of family planning knowledge, there were discrepancies in clients' everyday practices. Male and female clients are confronted with a variety of expectations concerning fertility intentions and family size, and are under pressure in numerous ways. Social pressures include traditional expectations and meanings connected to having children, as well as religious factors. Short interaction time between clients and health workers is a problem. Additionally, imposed contraceptive methods, and typically brief conversations about birth control between couples only adds to the burden. Because family planning is largely viewed as a woman's concern, most clients have never attended counselling sessions with their partners. Attitudes towards responsibility for contraceptive use and risk-taking are strongly gendered. Conclusions: Female and male clients have differing expectations about contraceptive use and fertility intentions. They participate differently in family planning programs leading to their inconsistent and ambivalent practices as well as vague perceptions of risk-taking. Therefore, policymakers must address the reasons behind ambivalence and inconsistency regarding contraceptives and family planning