Using the Makkai's duality for first-order logic, we characterise effective descent morphisms in 2-categories of pretoposes and Barr-exact categories. In both cases they coincide with conservative morphisms. We show that in those 2-categories the 2-coregular factorisations are exactly quotient-conservative factorisations. We also prove a generalisation of the Makkai duality for pseudoelementary categories.

The topos theory gives tools for unified proofs of theorems for model theory for various semantics and logics. We introduce the notion of power and the notion of generalized quantifier in topos and we formulate sufficient condition for such quantifiers in order that they fulfil downward Skolem-Löwenheim theorem when added to the language. In the next paper, in print, we will show that this sufficient condition is fulfilled in a vast class of Grothendieck toposes for the general and the existential (...) quantifiers. (shrink)

This paper is a continuation of the investigation from [13]. The main theorem states that the general and the existential quantifiers are (, -reducible in some Grothendieck toposes. Using this result and Theorems 4.1, 4.2 [13] we get the downward Skolem-Löwenheim theorem for semantics in these toposes.

In the paper [8], the first author developped a topos- theoretic approach to reference and modality. (See also [5]). This approach leads naturally to modal operators on locales (or spaces without points). The aim of this paper is to develop the theory of such modal operators in the context of the theory of locales, to axiomatize the propositional modal logics arising in this context and to study completeness and decidability of the resulting systems.

We show that (contrary to the parallel case of intuitionistic logic, see [7], [4]) there does not exist a translation fromS42 (the propositional modal systemS4 enriched with propositional quantifiers) intoS4 that preserves provability and reduces to identity for Boolean connectives and.

A. M. Pitts in [Pi] proved that HA op fp is a bi-Heyting category satisfying the Lawrence condition. We show that the embedding $\Phi: HA^\mathrm{op}_\mathrm{fp} \longrightarrow Sh(\mathbf{P_0,J_0})$ into the topos of sheaves, (P 0 is the category of finite rooted posets and open maps, J 0 the canonical topology on P 0 ) given by $H \longmapsto HA(H,\mathscr{D}(-)): \mathbf{P_0} \longrightarrow \text{Set}$ preserves the structure mentioned above, finite coproducts, and subobject classifier, it is also conservative. This whole structure on HA op (...) fp can be derived from that of Sh(P 0 ,J 0 ) via the embedding Φ. We also show that the equivalence relations in HA op fp are not effective in general. On the way to these results we establish a new kind of duality between HA op fp and a category of sheaves equipped with certain structure defined in terms of Ehrenfeucht games. Our methods are model-theoretic and combinatorial as opposed to proof-theoretic as in [Pi]. (shrink)

This paper proposes a unified dependent type analysis of three puzzling phenomena: inversely linked interpretations, weak definite readings in possessives and Haddock-type readings. We argue that the three problematic readings have the same underlying surface structure, and that the surface structure postulated can be interpreted properly and compositionally using dependent types. The dependent type account proposed is the first, to the best of our knowledge, to formally connect the three phenomena. A further advantage of our proposal over previous analyses is (...) that it offers a principled solution to the puzzle of why both inversely linked interpretations and weak definite readings are blocked with certain prepositions. (shrink)

Under some assumptions on an equational theory S , we give a necessary and sufficient condition so that S admits a model completion. These assumptions are often met by the equational theories arising from logic. They say that the dual of the category of finitely presented S-algebras has some categorical stucture. The results of this paper combined with those of [7] show that all the 8 theories of amalgamable varieties of Heyting algebras [12] admit a model completion. Further applications to (...) varieties of modal algebras are given in [8]. (shrink)

For a complete Heyting lattice , we define a category Etale (). We show that the category Etale () is equivalent to the category of the sheaves over , Sh(), hence also with -valued sets, see [2], [1]. The category Etale() is a generalization of the category Etale (X), see [1], where X is a topological space.

This chapter outlines an embodied conception of noise. From an enactive and ecological perspective noise is an inevitable complement to the richness of bodily sensitivities and complex actions. The world around us, the universe, is replete, full of inexhaustible texture available to be explored at every scale at which we are capable, or can become capable, of making distinctions. Drawing on work in ecological psychology I suggest that noise is our experience of that encompassing fullness, and can be encountered in (...) a number of different ways depending on the organisation of our bodies and activities at different scales across a given period. While that fullness can be overwhelming, and create challenges for us to distinguish and coordinate effectively with the particular aspects of the world most relevant to our present concerns - noise can be intrusive and disruptive - I argue that there are significant positive aspects to the phenomenon. Noise is an inherent part of the rich messiness of the world as discussed in recent enactive work, which provides both robustness to developmental processes as well as opportunities for action that support adaptive agency. In a noisy, messy world there are always more options available to explore. (shrink)

Descriptions of bodies within the literature of the enactive approach to cognitive science exhibit an interesting dialectical tension. On the one hand, a body is considered to be a unity which instantiates an identity, forming an intrinsic basis for value. On the other, a living body is in a reciprocally defining relationship with the environment, and is therefore immersed and entangled with, rather than distinct from, its environment. In this paper I examine this tension, and its implications for the enactive (...) approach, particularly the enactive conceptions of life and bodies. Following the lead of others, I argue that enactive cognitive science can benefit from a deeper reading and integration with extant work on the complexity and multiplicity of the living body within feminist philosophy and feminist science studies. (shrink)

Can we see the expressiveness of other people's gestures, hear the intentions in their voice, see the emotions in their posture? Traditional theories of social cognition still say we cannot because intentions and emotions for them are hidden away inside and we do not have direct access to them. Enactive theories still have no idea because they have so far mainly focused on perception of our physical world. We surmise, however, that the latter hold promise since, in trying to understand (...) cognition, enactive theory focuses on the embodied engagements of a cognizer with his world. In this paper, we attempt an answer for the question What is social perception in an enactive account? In enaction, perception is conceived as a skill, crucially involving action, an ability to work successfully within the set of regularities, or contingencies that characterize a given domain. If this is the case, then social perception should be a social skill. Having thus transformed the question of what social perception is into that of what social skill is, we examine the concept of social contingencies and the manner in which social skills structure—both constrain and empower— social interaction. Some of the implications of our account for how social and physical perception differ, the role of embodiment in social interaction and the distinction between our approach and other social contingency theories are also addressed. (shrink)

Die Beiträge zur Altertumskunde enthalten Monographien, Sammelbände, Editionen, Übersetzungen und Kommentare zu Themen aus den Bereichen Klassische, Mittel- und Neulateinische Philologie, Alte Geschichte, Archäologie, Antike Philosophie sowie Nachwirken der Antike bis in die Neuzeit. Dadurch leistet die Reihe einen umfassenden Beitrag zur Erschließung klassischer Literatur und zur Forschung im gesamten Gebiet der Altertumswissenschaften.

The world of Jedi is very different from our own, that their awareness of the universe is more encompassing, richer. The Jedi call that mystical aspect of reality they perceive the Force. Jedi younglings and padawans must put their body to new uses, perform new tasks, and learn new skills in physical activities that have profound effects on the way they see the world around them. What the Jedi say more than anything else about the Force is that it flows. (...) Jedi who are able to coordinate their actions with that flow can work with the full potency of the universal relationship between all things. Jedi do not need a special Force‐organ to perceive the Force. The Force is not something Jedi just see, or hear, or taste, or touch, but rather it is something they experience on its own terms, probably using their whole body to do it. (shrink)

Enactive and ecological approaches to cognitive science both claim a “mutuality” between agents and their environments – that they have a complementary nature and should be addressed as a single whole system. Despite this apparent agreement, each offers criticisms of the other on precisely this point – enactivists claiming that ecological psychologists over-emphasise the environment, while the complementary criticism, of agent-centred constructivism, is levelled by ecological psychologists at enactivists. In this paper I suggest that underlying the confusion between the two (...) approaches is the complexity of agency, which comes in different forms, at different scales or levels of analysis. Cognitive science has not theorised the relationship between these different forms in a sufficiently disciplined manner, and a task therefore remains of finding a way to map the complex territory of agency. (shrink)

ABSTRACT The Gödel–Dummett logic and Łukasiewicz one are two main many-valued logics used by the fuzzy logic community. Our goal is a quantitative comparison of these two. In this paper, we will mostly consider the 3-valued Gödel–Dummett logic as well as the 3-valued Łukasiewicz one. We shall concentrate on their implicational-negation fragments which are limited to formulas formed with a fixed finite number of variables. First, we investigate the proportion of the number of true formulas of a certain length n (...) to the number of all formulas of such length built with exactly one variable. Then, we investigate such proportion for satisfiable formulas. Second, we generalise our investigation on formulas written with $ k\ge 1 $ k ≥ 1 variables. The primary goal of the paper is the research on the asymptotic behaviour of these fractions when the length n tends to infinity. If such limits exists, they are real numbers between 0 and 1, which are called the density of truth or the density of SAT. To compare the density of truth and the density of satisfiable formulas for both fragments of 3-valued Gödel–Dummett's and Łukasiewicz's logics we use the powerful theory of analytic combinatorics. This paper is a natural continuation of the previous brief conference note by Kostrzycka and Zaionc (2020) as well as enriched with some previous results from Kostrzycka and Zaionc (2003). In the conference note we computed analytically the density of truth and the density of SAT (with a determined precision) for 3-valued Łukasiewicz's logic restricted to a language with only one variable. In Kostrzycka and Zaionc (2003) we computed the same values for exactly the same fragment of the 3-valued Gödel–Dummett logic. This paper answers the more general questions of the existence of density of truth and density of SAT for both many-valued logics with an arbitrary finite number of variables. Therefore this paper gives an an interesting picture of two main families of finite-valued fuzzy logics problems treated quantitatively. This picture is taken from the perspective of classical logic. It shows that unexpectedly there is quantitatively a little distance between these two approaches. (shrink)

The subject of the book is a reconsideration of the internalistic model of composition of the Platonic type, and its application in the ontology of quantum theory. Nonseparability is at the centre of quantum ontology. Quantum wholes are atemporal wholes governed by internalistic logic, requiring a relativization of fundamental notions of mechanics.

Jaśkowski’s discussive logic D2 was formulated with the help of the modal logic S5 as follows (see [7, 8]): \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${A \in {D_{2}}}$$\end{document} iff \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\ulcorner\diamond{{A}^{\bullet}}\urcorner \in {\rm S}5}$$\end{document}, where (–)• is a translation of discussive formulae from Ford into the modal language. We say that a modal logic L defines D2 iff \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm D}_{2} = (...) \{A \in {\rm For^{\rm d}} : \ulcorner\diamond{{A}^{\bullet}}\urcorner \in {\it L}\}}$$\end{document}. In [14] and [10] were respectively presented the weakest normal and the weakest regular logic which (†): have the same theses beginning with ‘\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\diamond}$$\end{document}’ as S5. Of course, all logics fulfilling the above condition, define D2. In [10] it was prowed that in the cases of logics closed under congruence the following holds: defining D2 is equivalent to having the property (†). In this paper we show that this equivalence holds also for all modal logics which are closed under replacement of tautological equivalents (rte-logics).We give a general method which, for any class of modal logics determined by a set of joint axioms and rules, generates in the given class the weakest logic having the property (†). Thus, for the class of all modal logics we obtain the weakest modal logic which owns this property. On the other hand, applying the method to various classes of modal logics: rte-logics, congruential, monotonic, regular and normal, we obtain the weakest in a given class logic defining D2. (shrink)

Perceptual modalities have been traditionally considered the product of dedicated biological systems producing information for higher cognitive processing. Psychological and neuropsychological evidence is offered which undermines this point of view and an alternative account of modality from the enactive approach to understanding cognition is suggested. Under this view, a perceptual modality is a stable form of perception which is structured not just by the biological sensitivities of the agent, but by their goals and the set of skills or expertise which (...) they are deploying at a given time. Such a view suggests that there is no such thing as an experience that is purely visual, auditory, or otherwise modal and that our attempts to understand consciousness and the mind must be conducted within a framework that provides an account of embodied, goal-directed adaptive coping with the world. (shrink)

Dotyczy: przestrzeń, czas, ciało, kognitywistyka, fenomenologia.

The book deals with distorted humanities and social sciences and examines alternatives. The topic is analysed in a way that is ground-breaking in its global comparison of research in Central Europe, Latin America, China, Russia, Africa and India.