Research on natural and artificial brains is proceeding at a rapid pace. However, the understanding of the essence of consciousness has changed slightly over the millennia, and only the last decade has brought some progress to the area. Scientific ideas emerged that the soul could be a product of the material body and that calculating machines could imitate brain processes. However, the authors of this book reject the previously common dualism—the view that the material and spiritual-psychic processes are separate and (...) require a completely different substance as their foundation. -/- Reductive Model of the Conscious Mind is a forward-thinking book wherein the authors identify processes that are the essence of conscious thinking and place them in the imagined, simplified structure of cells able to memorize and transmit information in the form of impulses, which they call neurons. The purpose of the study is to explain the essence of consciousness to the degree of development of natural sciences, because only the latter can find a way to embed the concept of the conscious mind in material brains. The book is divided into three parts. Part 1 works to convince readers that the emergence of consciousness does not require detailed knowledge of the structure and morphology of the brain, with the exception of some specific properties of the neural network structure that the authors attempt to point out. Part 2 proves that the biological structure of many natural brains fulfills the necessary conditions for consciousness and intelligent thinking. Similarly, Part 3 shows the ways in which artificial creatures imitating natural brains can meet these conditions, which gives great hopes for building artificially intelligent beings endowed with consciousness. Covering topics that include cognitive architecture, the embodied mind, and machine learning, this book is ideal for cognitive scientists, philosophers of mind, neuroscientists, psychologists, researchers, academicians, and advanced-level students. The book can also help to focus the research of linguists, neurologists, and biophysicists on the biophysical basis of postulated information processing into knowledge structures. (shrink)

This volume explores the range of Alfred North Whitehead's philosophy and his relevance to contemporary philosophical traditions.

Agresja putinowskiej Rosji na Ukrainę postawiła wobec dramatycznego wyzwania nobliwą doktrynę non‑violence. Zgodnie ze sformułowanym w latach 80. XX wieku wywodem antysowieckiego dysydenta rosyjskiego Władimira Bukowskiego to nie wojna jest przeciwieństwem pokoju, lecz przemoc, a do jej powstrzymania niekiedy konieczny jest zbrojny opór, czyli prowadzenie wojny. Według Clausewitza do wywołania stanu wojny nie wystarczy militarna agresja, lecz konieczne jest przeciwstawienie się jej, czyli aktywna obrona ze strony napadniętego, chcąc zatem uniknąć wojny, nie należy stawiać oporu agresorowi. Agresja na Ukrainę złamała (...) dwie zasady prowadzenia wojen: ius ad bellum i ius in bello. Według typologii Michaela Walzera jest to zatem niesprawiedliwa wojna prowadzona niesprawiedliwymi metodami, więc przeciwstawianie się jej, także militarne, jest prowadzeniem wojny sprawiedliwej. Zgodnie z analizą Slavoja Žižka tworzy to klarowną z etycznego punktu widzenia sytuację, zło jest łatwo identyfikowalne, a przeciwstawienie się mu stanowi etyczny obowiązek. Według filozofa Étienne’a Balibara w tej sytuacji pacyfizm nie jest żadną opcją. Helplessness as Acquiescence to Evil The aggression of Putin’s Russia towards Ukraine has posed a dramatic challenge to the noble doctrine of non-violence. In line with an argument made in the 1980s by anti-Soviet Russian dissident Vladimir Bukovsky, war is not the opposite of peace; instead, violence is. Armed resistance, or warfare, is sometimes necessary to stop violence. According to Clausewitz, military aggression is insufficient to evoke a state of war; in its place, it is necessary to oppose aggression, i.e., actively mount a defense by the attacked party, thereby avoiding war requires not resisting the aggressor. However, the aggression against Ukraine broke two tenets of warfare: ius ad bellum and ius in bello. According to Michael Walzer’s typology, it is an unjust war waged by unjust methods, so resisting it, including militarily, amounts to waging a just war. According to Slavoj Žižek’s analysis, this establishes an ethically clear situation: evil is easily identifiable, and opposing it is an ethical duty. According to the philosopher Étienne Balibar, pacifism is not an option in such a situation. (shrink)

Liberalism and political polarization: The customary classification of the ideological doctri‑ nes in democratic systems, which expanded along a left–right axis, is nowadays obsolescent and has been deconstructed. At the same time, the close and strong connection between de‑ mocracy and liberalism, on which the primary model of liberal democracy was established, has been broken in many places of the world. The emerging of illiberal democracies has made the liberal component the main criterion for the classification of contemporary political systems, (...) instead of dividing them into democratic and nondemocratic systems as before. Numerous ideological options could also be classified as being contrary to the liberal one. Liberalism has thus become important in the typologies and analyses of contemporary political systems and ideological options as the opposite to those systems on many new axes. (shrink)

This book offers a bold and controversial new thesis regarding the nature of prejudice. The authors' central claim is that prejudice is not simply learned, rather it is predisposed in all human beings and is thus the foundation for ethical valuation. They aim to destroy the illusion that prejudice is merely the result of learned beliefs, socially conditioned attitudes, or pathological states of development. Contrary to traditional accounts, prejudice itself is not a negative attribute of human nature, rather it is (...) the necessary precondition for the self and civilization to emerge. Defined as the preferential self-expression of valuation, prejudice gives rise to greater existential complexities and novelties that elevate selfhood and society to higher states of ethical realization. Rather than offer another contribution that highlights the destructive nature of prejudice, Mills and Polanowski address the ontological, psychological, and dialectical origins of prejudice as it manifests itself in the process of selfhood and culture. They provide an original conceptualization of the phenomenology of prejudice and its dialectical instantiation in the ontology of the individual, worldhood, and the very structures of subjectivity. As a unique synthesis of psychoanalysis, Hegelian idealism, Heideggerian existential ontology, and Whiteheadian process philosophy, prejudice is the indispensable ground for humanity to actualize its highest potentiality-for-Being. The striking result is (1) a revolutionary theory of human nature, (2) a new ethical system, and (3) the elevation of dialectical ethics to the domain of metaphysics. (shrink)

The article explores the concept of infodemics during the COVID-19 pandemic, focusing on the propagation of false or inaccurate information proliferating worldwide throughout the SARS-CoV-2 health crisis. We provide an overview of disinformation, misinformation and malinformation and discuss the notion of “fake news”, and highlight the threats these phenomena bear for health policies and national and international security. We discuss the mis-/disinformation as a significant challenge to the public health, intelligence, and policymaking communities and highlight the necessity to design measures (...) enabling the prevention, interdiction, and mitigation of such threats. We then present an overview of selected opportunities for applying technology to study and combat disinformation, outlining several approaches currently being used to understand, describe, and model the phenomena of misinformation and disinformation. We focus specifically on complex networks, machine learning, data- and text-mining methods in misinformation detection, sentiment analysis, and agent-based models of misinformation spreading and the detection of misinformation sources in the network. We conclude with the set of recommendations supporting the World Health Organization’s initiative on infodemiology. We support the implementation of integrated preventive procedures and internationalization of infodemic management. We also endorse the application of the cross-disciplinary methodology of Crime Science discipline, supplemented by Big Data analysis and related information technologies to prevent, disrupt, and detect mis- and disinformation efficiently. (shrink)

The class of equivalential logics comprises all implicative logics in the sense of Rasiowa [9], Suszko's logic SCI and many others. Roughly speaking, a logic is equivalential iff the greatest strict congruences in its matrices are determined by polynomials. The present paper is the first part of the survey in which systematic investigations into this class of logics are undertaken. Using results given in [3] and general theorems from the theory of quasi-varieties of models [5] we give a characterization of (...) all simple C-matrices for any equivalential logic C. In corollaries we give necessary and sufficient conditions for the class of all simple models for a given equivalential logic to be closed under free products. (shrink)

Once regarded as cellular ‘debris’ extracellular vesicles (EVs) emerge as one of the most intriguing entities in cancer pathogenesis. Intercellular trafficking of EVs challenges the notion of cancer cell autonomy, and highlights the multicellular nature of such fundamental processes as stem cell niche formation, tumour stroma generation, angiogenesis, inflammation or immunity. Recent studies reveal that intercellular exchange mediated by EVs runs deeper than expected, and includes molecules causative for cancer progression, such as oncogenes (epidermal growth factor receptor, Ras), and tumour (...) suppressors (PTEN). The uptake of oncogenic EVs (oncosomes) by various cells may profoundly change their biology, signalling patterns and gene expression, and in some cases cause their overt tumorigenic conversion. Moreover, EVs circulating in blood and present in body fluids provide an unprecedented access to the molecular circuitry driving cancer cells, and new technologies are being developed to exploit this property as a source of unique cancer biomarkers. (shrink)

The notion of local deduction theorem (which generalizes on the known instances of indeterminate deduction theorems, e.g. for the infinitely-valued ukasiewicz logic C ) is defined. It is then shown that a given finitary non-pathological logic C admits the local deduction theorem iff the class Matr(C) of all matrices validating C has the C-filter extension property (Theorem II.1).

In the paper we study the class of weakly algebraizable logics, characterized by the monotonicity and injectivity of the Leibniz operator on the theories of the logic. This class forms a new level in the non-linear hierarchy of protoalgebraic logics.

This study investigates performance of portfolios composed of British socially responsible investments (SRI) stocks. Using the ‘Global-100 Most Sustainable Corporations in the World’ list (known also as ‘Global-100’) to select the SRI companies, we found that, in the period 2000–2010, the returns of the SRI portfolios were on average higher compared with the corresponding returns of the market indexes. The annual average difference in returns of the SRI portfolios (with dividends) was 5.26 % and 5.69 % relative to the FTSE100 (...) and FTSE4GOOD indexes (the total return versions), respectively, but the differences in returns in the whole period, in individual years and in other sub-periods were in most cases not statistically significant. Positive performance of SRI stocks in the whole sample is, however, evidenced by risk-adjusted measures such as the modified Sharpe ratio (MSR) and certainty equivalent (CEQ) returns, as well as by incorporating various levels of transaction costs. Furthermore, a simple trading strategy relying on selection of SRI stocks from the Global-100 list would beat the market indexes in the whole period 2000–2010, even after inclusion of various levels of transaction costs. We also estimated the Fama–French and Carhart multi-factor models and found that the returns of the SRI portfolios cannot be consistently explained by conventional factors other than the market factor. (shrink)

We propose a new schema for the deduction theorem and prove that the deductive system S of a prepositional logic L fulfills the proposed schema if and only if there exists a finite set A(p, q) of propositional formulae involving only prepositional letters p and q such that A(p, p) L and p, A(p, q) s q.

The main result of the present paper — Theorem 3 — establishes the equivalence of the interpolation and amalgamation properties for a large family of logics and their associated classes of matrices.

The class of equivalential logics comprises all implicative logics in the sense of Rasiowa [9], Suszko's logicSCI and many Others. Roughly speaking, a logic is equivalential iff the greatest strict congruences in its matrices (models) are determined by polynomials. The present paper is the first part of the survey in which systematic investigations into this class of logics are undertaken. Using results given in [3] and general theorems from the theory of quasi-varieties of models [5] we give a characterization of (...) all simpleC-matrices for any equivalential logicC (Theorem I.14). In corollaries we give necessary and sufficient conditions for the class of all simple models for a given equivalential logic to be closed under free products (Theorem I.18). (shrink)

Psychological research is based on philosophical assumptions which are not always explicitly formulated. On the other hand, the results of these investigations affect philosophical thinking and the conception of human nature. For a long time it was a ruling conception in psychology that the essence of human nature consists in the existence of driving mechanisms with homeostatic properties drives or needs – which, principally, are inborn mechanisms modified by learning. The analysis of driving mechanisms founded on psychological and neuro-physiological data, (...) brought about a modification of this traditional view. Starting from the concept of need as an objective phenomenon it can be stated that the higher organisms have a special mechanisms securing the satisfaction of needs. They are drives. These mechanisms do not exist in a ready form in man but only potentially, as an ability to organize a functional unit in result of certain experience. The formation of drives includes: making connections between certain internal stimuli and some forms of activity reducing these stimuli; learning how to find things which are necessary to reduce them; and, finally, the acquisition of the ability to give verbal labels to the occurring processes. In consequence, the final form of a drive is determined by biological and social factors as well as by individual experiences. (shrink)

The paper is conceived as a first study on the Suszko operator. The purpose of this paper is to indicate the existence of close relations holding between the properties of the Suszko operator and the structural properties of the model class for various sentential logics. The emphasis is put on generality both of the results and methods of tackling the problems that arise in the theory of this operator. The attempt is made here to develop the theory for non-protoalgebraic logics.

The paper is conceived as a first study on the Suszko operator. The purpose of this paper is to indicate the existence of close relations holding between the properties of the Suszko operator and the structural properties of the model class for various sentential logics. The emphasis is put on generality both of the results and methods of tackling the problems that arise in the theory of this operator. The attempt is made here to develop the theory for non-protoalgebraic logics.

The first known statements of the deduction theorems for the first-order predicate calculus and the classical sentential logic are due to Herbrand [8] and Tarski [14], respectively. The present paper contains an analysis of closure spaces associated with those sentential logics which admit various deduction theorems. For purely algebraic reasons it is convenient to view deduction theorems in a more general form: given a sentential logic C (identified with a structural consequence operation) in a sentential language I, a quite arbitrary (...) set P of formulas of I built up with at most two distinct sentential variables p and q is called a uniform deduction theorem scheme for C if it satisfies the following condition: for every set X of formulas of I and for any formulas and , C(X{{a}}) iff P(, ) AC(X). [P(, ) denotes the set of formulas which result by the simultaneous substitution of for p and for q in all formulas in P]. The above definition encompasses many particular formulations of theorems considered in the literature to be deduction theorems. Theorem 1.3 gives necessary and sufficient conditions for a logic to have a uniform deduction theorem scheme. Then, given a sentential logic C with a uniform deduction theorem scheme, the lattices of deductive filters on the algebras A similar to the language of C are investigated. It is shown that the join-semilattice of finitely generated (= compact) deductive filters on each algebra A is dually Brouwerian. (shrink)

In the first section logics with an algebraic semantics are investigated. Section 2 is devoted to subdirect products of matrices. There, among others we give the matrix counterpart of a theorem of Jónsson from universal algebra. Some positive results concerning logics with, finite degrees of maximality are presented in Section 3.

Although it became customary to warn against confusing postmodernism with deconstructionism, it seems plausible to suggest that their central agendas are not dissimilar. Moreover, from the philosophical point of view, it is the idea of the 'deconstruction of meaning' that can be said to constitute the foundation of postmodernism understood here as an intellectual movement. It is true that grounded in the poststructuralist language analysis, deconstructionism seeks primarily to challenge the attempts inherent in the Western philosophical tradition to establish ultimate (...) meaning in a text. However, as one might have anticipated, the deconstruction of meaning of texts provided a basis for a large scale project leading to deconstruction of all 'truths', as conceived in the mainstream philosophical tradition. And it did it by questioning the coherence of the very concept of 'truth'. Eclectic as postmodernism is, it can be recognized by the fundamental assumption that there is no common denominator that guarantees the one-ness of the world, or the possibility of objective or neutral thought. This assumption would suffice to make one expect that postmodernism will challenge the very foundations of any metaphysical or religious system of beliefs. And so it does. In this paper I would like to ellucidate just one way this challange may be construed, poiting to the example of Don Cupitt, the leading exponent of the 'antirealist' critique of the discourse of theism. (shrink)

Although it became customary to warn against confusing postmodernism with deconstructionism, it seems plausible to suggest that their central agendas are not dissimilar. Moreover, from the philosophical point of view, it is the idea of the 'deconstruction of meaning' that can be said to constitute the foundation of postmodernism understood here as an intellectual movement. It is true that grounded in the poststructuralist language analysis, deconstructionism seeks primarily to challenge the attempts inherent in the Western philosophical tradition to establish ultimate (...) meaning in a text. However, as one might have anticipated, the deconstruction of meaning of texts provided a basis for a large scale project leading to deconstruction of all 'truths', as conceived in the mainstream philosophical tradition. And it did it by questioning the coherence of the very concept of 'truth'. Eclectic as postmodernism is, it can be recognized by the fundamental assumption that there is no common denominator that guarantees the one-ness of the world, or the possibility of objective or neutral thought. This assumption would suffice to make one expect that postmodernism will challenge the very foundations of any metaphysical or religious system of beliefs. And so it does. In this paper I would like to ellucidate just one way this challange may be construed, poiting to the example of Don Cupitt, the leading exponent of the 'antirealist' critique of the discourse of theism. (shrink)

The class Matr(C) of all matrices for a prepositional logic (, C) is investigated. The paper contains general results with no special reference to particular logics. The main theorem (Th. (5.1)) which gives the algebraic characterization of the class Matr(C) states the following. Assume C to be the consequence operation on a prepositional language induced by a class K of matrices. Let m be a regular cardinal not less than the cardinality of C. Then Matr (C) is the least class (...) of matrices containing K and closed under m-reduced products, submatrices, matrix homomorphisms, and matrix homomorphic counter-images. (shrink)

We examine the notion of primitive satisfaction in logical matrices. Theorem II. 1, being the matrix counterpart of Baker's well-known result for congruently distributive varieties of algebras (cf [1], Thm. 1.5), links the notions of primitive and standard satisfaction. As a corollary we give the matrix version of Jónsson's Lemma, proved earlier in [4]. Then we investigate propositional logics with disjunction. The main result, Theorem III. 2, states a necessary and sufficient condition for such logics to be finitely based.

In 1948, Stanis aw Ja kowski defined a logical system D2 of a discursive 1 sentential calculus. The aim of this paper is to introduce the reader to the basic ideas of the discursive logic and to show, in a historical perspective, its development originating from the two germ papers [19] and [20]. We intend to present some problems connected with it and outline the solutions they have received up to the present day.

This paper, being a companion to the book [2] elaborates the deontology of sequential and compound actions based on relational models and formal constructs borrowed from formal linguistics. The semantic constructions presented in this paper emulate to some extent the content of [3] but are more involved. Although the present work should be regarded as a sequel of [3] it is self-contained and may be read independently. The issue of permission and obligation of actions is presented in the form of (...) a logical system. This system is semantically defined by providing its intended models in which the role of actions of various types is accentuated. Since the consequence relation is not finitary, other semantically defined variants of are defined. The focus is on the finitary system in which only finite compound actions are admissible. An adequate axiom system for it is defined. The strong completeness theorem is the central result. The role of the canonical model in the proof of the completeness theorem is emphasized. (shrink)

In this paper, we present a calculus of paraconsistent logic. We propose an axiomatisation and a semantics for the calculus, and prove several important meta-theorems. The calculus, denoted as CB1, is an extension of systems PI, C min and B1, and a proper subsystem of Sette’s calculus P1. We also investigate the generalization of CB1 to the hierarchy of related calculi.

The article discusses the philosophical problems associated with the dualistic conception of the person dominant in traditions influenced by Platonism. The key suggestion made in the article is that opting for an embodied rather than a disembodied posthumous existence for the human person will in no way hinder the theistic philosopher when it comes to arguing that God exists in a disembodied form.

W maju 1998 roku odbyła się w Monachium międzynarodowa konferencja poświęcona zagadnieniu racjonalności teizmu. Temat to szeroko dyskutowany w ostatnich czasach, stąd wydawać by się mogło, że zorganizowanie jeszcze jednej sesji, która przyciągnęłaby uwagę środowiska filozofów religii, będzie przedsięwzięciem wyjątkowo trudnym. Tymczasem monachijska debata zasłużyła sobie na miano wydarzenia. O jej atrakcyjności zadecydował fakt, że została pomyślana jako próba ożywienia dialogu pomiędzy filozofami nawiązującymi do tradycji kontynentalnej z przedstawicielami filozofii analitycznej. Tego rodzaju ekumeniczne inicjatywy nalezą w tej dziedzinie do rzadkości. (...) Ten swoisty izolacjonizm ma wiele przyczyn, a kością niezgody jest między innymi stosunek do Kanta. Postkantowska kontynentalna filozofia religii, kładąca nacisk na epistemologię i fenomenologię doświadczenia religijnego, postrzega anglosaski renesans badań nad klasycznymi problemami teodycealnymi jako nawrót do przedkrytycznego dogmatyzmu. Z kolei niektórzy analityczni filozofowie religii zdają się uprawiać swą dyscyplinę w taki sposób, jak gdyby kopernikański przewrót Kanta uważali za niebyły, a czasem nazywają expressis verbis epoką nowożytną okresem błędów i wypaczeń. Epistemologiczne zagadnienie racjonalności religii należy do kręgu zainteresowań obydwu wymienionych tradycji, stad możliwe jest tu połączenie wysiłków w celu uporządkowania tematyki i oceny aktualnego stanu refleksji. (shrink)

Does the alleged religious experience of a mystic constitute a reliable source of knowledge about the object of his or her experience? Or does it rationally justify a move from such experience to meaningful beliefs about God or the Absolute which is supposed to be the object of that experience? And are religious beliefs in need of being grounded in religious experience in order to be rationally justified? Although it seems pretty obvious that a great many adherents of all religions (...) find reasons for their beliefs in their religious traditions rather than in their personal religious experiences, one could note that usually these traditions present religious experiences of their founder figures as constituting evidence for their authenticity and truthfulness ; the supposed mystical experiences of some adherents of a given religious tradition are often treated by their co-believers as an important evidence which increases credibility of their own religious convictions. (shrink)

The present paper is thought as a formal study of distributive closure systems which arise in the domain of sentential logics. Special stress is laid on the notion of a C-filter, playing the role analogous to that of a congruence in universal algebra. A sentential logic C is called filter distributive if the lattice of C-filters in every algebra similar to the language of C is distributive. Theorem IV.2 in Section IV gives a method of axiomatization of those filter distributive (...) logics for which the class Matr (C) prime of C-prime matrices (models) is axiomatizable. In Section V, the attention is focused on axiomatic strengthenings of filter distributive logics. The theorems placed there may be regarded, to some extent, as the matrix counterparts of Baker's well-known theorem from universal algebra [9, § 62, Theorem 2]. (shrink)

Situational aspects of action are discussed. The presented approach emphasizes the role of situational contexts in which actions are performed. These contexts influence the course of an action; they are determined not only by the current state of the system but also shaped by other factors as time, the previously undertaken actions and their succession, the agents of actions and so on. The distinction between states and situations is explored from the perspective of action systems. The notion of a situational (...) action system is introduced and its theory is expounded. Numerous examples illustrate the reach of the theory. (shrink)

The paper is a response to recent criticisms of agatheism, a new pluralistic interpretation of religious belief put forward by Janusz Salamon with the aim of accommodating the epistemological challenge of religious diversity. Agatheism is an axiologically grounded religious belief which identifies God, the Absolute or the ultimate reality religiously conceived with the ultimate good as the ultimate end of all human agency and thus an explanation of its irreducibly teleological character and a source of its meaning. Janusz (...) Salamon argues that this grounding of religious belief in the human axiological consciousness makes it immune to falsification by any future science. Replying to the concerns of the critics about about irrationality of doxastic commitment to a particular religious tradition, Janusz Salamon argues that to the extent the fundamental agatheistic religious belief is presupposed in such tradition as its doxastic core, its belief system - if internally coherent and aligned with a worldview that is consistent with undisputed scientific findings - may be considered rational, despite there being a plurality of such belief systems. (shrink)

In the paper we study the class of weakly algebraizable logics, characterized by the monotonicity and injectivity of the Leibniz operator on the theories of the logic. This class forms a new level in the non-linear hierarchy of protoalgebraic logics.

The paper is concerned with the old conjecture that there are infinitely many twin primes. In the paper we show that this conjecture is true, that is, it is true in the standard model of arithmetic. The proof is based on Rasiowa–Sikorski Lemma. The key role are played by the derived notion of a Rasiowa–Sikorski set and the method of forcing adjusted to arbitrary first–order languages. This approach was developed in the papers Czelakowski [ 4, 5 ]. The central idea (...) consists in constructing an appropriate countable model \(\textbf{A}\) of Peano arithmetic by means of a Rasiowa–Sikorski set. This model validates the twin prime conjecture. Since \(\textbf{A}\) is elementarily equivalent to the standard model, the conjecture follows. Thus the standard model validates the twin primes conjecture. More generally, it is shown that de Polignac’s conjecture has a positive solution. The paper employs methods borrowed from the contemporary mathematical logic. Such a ’logical’ approach may be viewed as a useful addition to the dominant methodology in number theory based on mathematical analysis. (shrink)

With each sentential logic C, identified with a structural consequence operation in a sentential language, the class Matr * (C) of factorial matrices which validate C is associated. The paper, which is a continuation of [2], concerns the connection between the purely syntactic property imposed on C, referred to as Maehara Interpolation Property (MIP), and three diagrammatic properties of the class Matr* (C): the Amalgamation Property (AP), the (deductive) Filter Extension Property (FEP) and Injections Transferable (IT). The main theorem of (...) the paper (Theorem 2.2) is analogous to the Wroski's result for equational classes of algebras [13]. It reads that for a large class of logics the conjunction of (AP) and (FEP) is equivalent to (IT) and that the latter property is equivalent to (MIP). (shrink)

In the late forties, Stanisław Jaśkowski published two papers onthe discursive sentential calculus, D2. He provided a definition of it by an interpretation in the language of S5 of Lewis. The knownaxiomatization of D2 with discursive connectives as primitives was introduced by da Costa, Dubikajtis and Kotas in 1977. It turns out, however,that one of the axioms they used is not a thesis of the real Jaśkowski’s calculus. In fact, they built a new system, D∗2 for short, that differs from (...) D2 inmany respects. The aim of this paper is to introduce a direct Kripke-type semantics for the system, axiomatize it in a new way and prove soundness andcompleteness theorems. Additionally, we present labelled tableaux for D∗2.1. (shrink)

An individual-based approach is used to describe population dynamics. Two kinds of models have been constructed with different distributions illustrating individual variability. In both models, the growth rate of an individual and its final body weight at the end of the growth period, which determines the number of offspring, are functions of the amount of resources assimilated by an individual. In the model with a symmetric distribution, the half saturation constant in the Michaelis–Menten function describing the relationship between the growth (...) of individuals and the amount of resources has a normal distribution. In the model with an asymmetric distribution, resources are not equally partitioned among individuals. The individual who acquired more resources in the past, will acquire more resources in the future. A single population comprising identical individuals has a very short extinction time. If individuals differ in the amount of food assimilated, this time significantly increases irrespectively of the type of model describing population dynamics. Individuals of two populations of competing species use common resources. For larger differences in individual variability, the more variable species will have a longer extinction time and will exclude less variable species. Both populations can also coexist when their variabilities are equal or even when they are slightly different, in the latter case under the condition of high variability of both species. These conclusions have a deterministic nature in the case of the model with the asymmetric distribution—repeated simulations give the same results. In the case of the model with the symmetric distribution, these conclusions are of a statistical nature—if we repeat the simulation many times, then the more variable species will have a longer extinction time more frequently, but some results will happen when the less variable species has a longer extinction time. Additionally, in the model with the asymmetric distribution, the result of competition will depend on the way of the introduction of variability into the model. If the higher variability is due to an increase in the proportion of individuals with a low assimilation of resources, it can produce a longer extinction time of the less variable species. (shrink)