The existence of spacetime singularities is one of the biggest problems of nowadays physics. According to Penrose, each physical singularity should be covered by a “cosmic censor” which prevents any external observer from perceiving their existence. However, classical models describing the gravitational collapse usually results in strong curvature singularities, which can also remain “naked” for a finite amount of advanced time. This proceedings studies the modifications induced by asymptotically safe gravity on the gravitational collapse of generic Vaidya spacetimes. It will (...) be shown that, for any possible choice of the mass function, quantum gravity makes the internal singularity gravitationally weak, thus allowing a continuous extension of the spacetime beyond the singularity. (shrink)

Five experiments are reported that concern selective perception and representation following dichotic presentations of competing word pairs differing only in their initial consonants . Only one word from each pair tended to be subjectively perceived, even when participants were encouraged to guess two words. Robust selective perception effects were evidenced as a function of stimulus affective valence. Control tasks showed that these effects could not be attributed to report biases or to the acoustic properties of the stimuli. The unreported words (...) were not recognized on a two-alternative forced-choice task but were recognized with a more sensitive ranking task. Additional cognitive activity during the intertrial interval weakened memory only for the words reported as perceived. Moreover, negative affective valence decreased the recognition of words reported as consciously perceived but increased recognition of unreported words. The implications of these findings for theories of unconscious processing are discussed. (shrink)

From the perspective of successive events, chemical reactions are expressed or thought about, in terms of the cause-effect category. In this work, I will firstly discuss some aspects of causation and interaction in chemistry, argue for the interaction, and propose an alternative or complementary representation scheme called “interaction diagram”, that allows representing chemical reactions through a geometric diagram. The understanding of this diagram facilitates the analysis of reactions in terms of the interaction, or reciprocal action, among the participating entities. Secondly, (...) I will describe the model and provide examples and finally, I will discuss the scope and limitations of the current development status of the model. (shrink)

For the past 20 years or so the literature on noncooperative games has been centered on the search for an equilibrium concept that expresses the notion of rational behavior in interactive situations. A basic tenet in this literature is that if a “rational solution” exists, it must be a Nash equilibrium. The consensus view, however, is that not all Nash equilibria can be accepted as rational solutions. Consider, for example, the game of Figure 1.

In the last decade, the notion of triad was reintroduced by Eric Scerri, who suggested it as a possible categorical criterion to represent chemical periodicity. In particular, he reformulated the notion of triad in terms of atomic number instead of atomic weights; in this way, the value of the intermediate term of the triad became the exact average of the values of the two extremes. Following the inspiration of Scerri’s work, the main purpose of this article is to obtain a (...) representation where all the relations among the chemical elements that form the groups of the periodic system can be reconstructed on the basis of triads, without using electronic configurations. (shrink)

The purpose of this work is to discuss which relation can be established between molecular chemistry, on the one hand, and macrochemistry and nanochemistry, on the other hand. In order to do this, we will consider molecular chemistry as an underlying level, and macrochemistry and nanochemistry as emergent levels. Emergence is characterized in very different ways in the philosophical literature; we will not discuss those differences. We will address a distinction between inter-domain emergence and intra-domain emergence. It is our purpose (...) to argue that, from a basal micro-molecular level, macrochemistry and nanochemistry emerge in parallel. The emergence of macrochemistry is an inter-domain emergence, while the emergence of the nanolevel is an intra-domain one. If this is the case, therefore macrochemistry and nanochemistry are not “successive” levels, but parallel ones. This discussion will be held from an ontological point of view, instead of the classical characterization in terms of scale. (shrink)

La metafora come strumento con il quale rinunciare a una teoria della definizione basata sulla sostanza, per preferire un linguaggio più evocativo.Metaphor as a tool by which giving up a substance based definition theory, in order to choose a more evocative language.

Il significato della metafora sta nelle nuove relazioni che si instaurano fra i termini, dunque essa fa esplodere il carattere puramente estensionale della classificazione porfiriana.

Nel processo di digitalizzazione dei testi sembrano emergere somiglianze e analogie con quegli anni del medioevo durante i quali si assiste all'incontro fra la tradizione latina occidentale e il patrimonio culturale di provenienza greca e araba. Due mondi che traducono per conoscere e per conservare: provare a confrontarli può aiutare a chiarire qualcosa sia dell'uno che dell'altro.

The association of resilience-related factors with frailty is a recent research topic. Dispositional optimism and context sensitivity are two psychological factors that differently contribute to individual resilience. This study aimed at investigating whether dispositional optimism and context sensitivity might contribute to a multifactorial model of frailty, together with established relevant factors such as cognitive and physical factors. This cross-sectional study involved 141 elderly outpatients aged ≥65 years, who were referred to the Geriatrics and Multidimensional Evaluation Clinic of the University Hospital (...) of Messina. We used the following measures: the Mini-Mental State Examination to screen for global cognitive functioning; 4-m gait speed and handgrip strength to measure physical performance; a 35-item Frailty Index to evaluate patients’ frailty status; the revised Life Orientation Test to gauge dispositional optimism; and the Context Sensitivity Index to measure context sensitivity. We found that LOT-R, CSI, and MMSE were all significantly associated with FI. Gait speed was only marginally associated with FI. The present study showed a novel association of dispositional optimism and context sensitivity with frailty among elderly outpatients. These preliminary findings support a multidimensional approach to frailty in which even peculiar psychological features might provide a significant contribution. (shrink)

We propose a modal logic based on three operators, representing intial beliefs, information and revised beliefs. Three simple axioms are used to provide a sound and complete axiomatization of the qualitative part of Bayes’ rule. Some theorems of this logic are derived concerning the interaction between current beliefs and future beliefs. Information flows and iterated revision are also discussed.

In his note Arnis Vilks raises two criticisms concerning my paper "The Logic of Rational Play in Extensive Games". The author gives two examples: one to show that my logic "is inconsistent.

Since belief revision deals with the interaction of belief and information over time, branching-time temporal logic seems a natural setting for a theory of belief change. We propose two extensions of a modal logic that, besides the next-time temporal operator, contains a belief operator and an information operator. The first logic is shown to provide an axiomatic characterization of the first six postulates of the AGM theory of belief revision, while the second, stronger, logic provides an axiomatic characterization of the (...) full set of AGM postulates. © 2006 Elsevier B.V. All rights reserved. (shrink)

The principle of belief persistence, or conservativity principle, states that ’\Nhen changing beliefs in response to new evidence, you should continue to believe as many of the old beliefs as possible' (Harman, 1986, p. 46). In particular, this means that if an individual gets new information, she has to accommodate it in her new belief set (the set of propositions she believes), and, if the new information is not inconsistent with the old belief set, then (1) the individual has to (...) maintain all the beliefs she previously had and (2) the change should be minimal in the sense that every proposition in the new belief set must be deducible from the union of the old belief set and the new information (see, e.g., Gardenfors, 1988; Stalnaker, 1984). We focus on this minimal notion of belief persistence and characterize it both semantically and syntactically. A ’possible world' semantic formalization of the principle easily comes to mind. The set of all the propositions that the individual believes corresponds to the set of states of the world that she considers possible and is a subset of the set of states that are not ruled out by the individual's information (or knowledge). It is required that, if the individual considers a state possible and her new information does not exclude this state, then she continue to consider it possible. Furthermore, if the individual regards a particular state as impossible, then she should continue to regard it as impossible unless her new information excludes all the states that she previously regarded as possible. This is closely related to the.. (shrink)

We establish a correspondence between the rationalizability of choice studied in the revealed preference literature and the notion of minimal belief revision captured by the AGM postulates. A choice frame consists of a set of alternatives , a collection E of subsets of (representing possible choice sets) and a function f : E ! 2 (representing choices made). A choice frame is rationalizable if there exists a total pre-order R on..

In this paper we will argue that the categories of physical individuals and chemical stuff are not sufficient to face the chemical ontology if nanomaterials are taken into account. From a perspective that considers ontological questions and wonders which the items involved in science are, we will argue that the domain of nanoscience must be considered as populated by entities that are neither individuals, as those of physics, nor stuff, as those items of macro-chemistry. This discussion, in virtue of the (...) analysis of the nature of nanomaterials, leads to propose a proper ontological category for nanoparticles: nanoindividuals. Nanomaterials are sorts of individuals, but they are different from physical individuals and from chemical stuff. We will also claim to contribute to the growing field of the philosophy of chemistry, especially regarding discussions that manifest not only epistemological but also ontological issues. In this scenario, the field on nanoscience is particularly challenging. (shrink)

We investigate an axiomatization of the notion of common belief that makes use of no rules of inference and highlight the property of the set of accessibility relations that characterizes each axiom.

The temporal updating of an agent’s beliefs in response to a flow of information is modeled in a simple modal logic that, for every date t, contains a normal belief operator B t and a non-normal information operator I t which is analogous to the ‘only knowing’ operator discussed in the computer science literature. Soundness and completeness of the logic are proved and the relationship between the proposed logic, the AGM theory of belief revision and the notion of plausibility is (...) discussed. (shrink)

The paper examines the social contradictions generated by patterns of reproduction of accumulation of capital, social legitimation and by present agricultural policies fostered by the State. Through a scrutiny of the role of the State in capitalism it is argued that agricultural overproduction, the widening of the gap between small and large farms, the fiscal crisis of the State associated with agricultural programs and waste of resources are the outcomes of an attempt on the part of the State to promote (...) simultaneously accumulation and legitimation. The possibility of enhancing accumulation and maintaining legitimation clashes with the diverse socio-economic demands associated with the present agricultural production system and the general viability of the social structure as a whole. (shrink)

The logic of common belief does not always reflect that of individual beliefs. In particular, even when the individual belief operators satisfy the KD45 logic, the common belief operator may fail to satisfy axiom 5. That is, it can happen that neither is A commonly believed nor is it common belief that A is not commonly believed. We identify the intersubjective restrictions on individual beliefs that are incorporated in axiom 5 for common belief.

The notion of perfect recall in extensive games was introduced by Kuhn (1953), who interpreted it as "equivalent to the assertion that each player is allowed by the rules of the game to remember everything he knew at previous moves and all of his choices at those moves''. We provide a characterization and axiomatization of perfect recall based on two notions of memory: (1) memory of past knowledge and (2) memory of past actions.

There is an ongoing debate in the philosophical literature whether the conditionals that are central to deliberation are subjunctive or indicative conditionals and, if the latter, what semantics of the indicative conditional is compatible with the role that conditionals play in deliberation. We propose a possible-world semantics where conditionals of the form “if I take action _a_ the outcome will be _x_” are interpreted as material conditionals. The proposed framework is illustrated with familiar examples and both qualitative and probabilistic beliefs (...) are considered. Issues such as common-cause cases and ‘Egan-style’ cases are discussed. (shrink)

We consider strategic-form games with ordinal payoffs and provide a syntactic analysis of common belief/knowledge of rationality, which we define axiomatically. Two axioms are considered. The first says that a player is irrational if she chooses a particular strategy while believing that another strategy is better. We show that common belief of this weak notion of rationality characterizes the iterated deletion of pure strategies that are strictly dominated by pure strategies. The second axiom says that a player is irrational if (...) she chooses a particular strategy while believing that a different strategy is at least as good and she considers it possible that this alternative strategy is actually better than the chosen one. We show that common knowledge of this stronger notion of rationality characterizes the restriction to pure strategies of the iterated deletion procedure introduced by Stalnaker (1994). Frame characterization results are also provided. (shrink)

We consider a basic logic with two primitive uni-modal operators: one for certainty and the other for plausibility. The former is assumed to be a normal operator, while the latter is merely a classical operator. We then define belief, interpreted as “maximally plausible possibility”, in terms of these two notions: the agent believes \ if she cannot rule out \ ), she judges \ to be plausible and she does not judge \ to be plausible. We consider four interaction properties (...) between certainty and plausibility and study how these properties translate into properties of belief. We then prove that all the logics considered are minimal logics for the highlighted theorems. We also consider a number of possible interpretations of plausibility, identify the corresponding logics and show that some notions considered in the literature are special cases of our framework. (shrink)

Counterexamples to two results by Stalnaker (Theory and Decision, 1994) are given and a corrected version of one of the two results is proved. Stalnaker's proposed results are: (1) if at the true state of an epistemic model of a perfect information game there is common belief in the rationality of every player and common belief that no player has false beliefs (he calls this joint condition ‘strong rationalizability’), then the true (or actual) strategy profile is path equivalent to a (...) Nash equilibrium; (2) in a normal-form game a strategy profile is strongly rationalizable if and only if it belongs to C8 , the set of profiles that survive the iterative deletion of inferior profiles. (shrink)

Two views of game theory are discussed: (1) game theory as a description of the behavior of rational individuals who recognize each other’s rationality and reasoning abilities, and (2) game theory as an internally consistent recommendation to individuals on how to act in interactive situations. It is shown that the same mathematical tool, namely modal logic, can be used to explicitly model both views.

The contributions to the Special Issue on Multiple Belief Change, Iterated Belief Change and Preference Aggregation are divided into three parts. Four contributions are grouped under the heading "multiple belief change" (Part I, with authors M. Falappa, E. Fermé, G. Kern-Isberner, P. Peppas, M. Reis, and G. Simari), five contributions under the heading "iterated belief change" (Part II, with authors G. Bonanno, S.O. Hansson, A. Nayak, M. Orgun, R. Ramachandran, H. Rott, and E. Weydert). These papers do not only (...) pick up the particular questions raised, but also extend and modify the framework of Alchourrón, Gärdenfors and Makinson. Part III deals with preference aggregation and consists of one contribution (by F. Herzberg and D. Eckert). (shrink)

In this book, Justin N. Bonanno builds off of the recent philosophical work on Walker Percy’s writings. While it is valuable to appreciate Percy as a novelist, Bonanno approaches Percy from the perspective of Continental philosophy and the rhetorical tradition. Unpacking the works of several key authors that influenced Percy (e.g. Sartre and Heidegger), Bonanno offers a fresh philosophical account of Percy's ideas concerning the relationship between symbols and existence. In particular, he focuses on how Percy’s ideas (...) emerge from the thought of Ernst Cassirer, Susanne Langer, Jacques Maritain, Jean-Paul Sartre, Gabriel Marcel, Martin Heidegger, Viktor Shklovsky, Søren Kierkegaard, and St. Thomas Aquinas. (shrink)

In an earlier paper [Rational choice and AGM belief revision, _Artificial Intelligence_, 2009] a correspondence was established between the set-theoretic structures of revealed-preference theory (developed in economics) and the syntactic belief revision functions of the AGM theory (developed in philosophy and computer science). In this paper we extend the re-interpretation of those structures in terms of one-shot belief revision by relating them to the trichotomous attitude towards information studied in Garapa (Rev Symb Logic, 1–21, 2020) where information may be either (...) (1) fully accepted or (2) rejected or (3) taken seriously but not fully accepted. We begin by introducing the syntactic notion of _filtered belief revision_ and providing a characterization of it in terms of a mixture of both AGM revision and contraction. We then establish a correspondence between the proposed notion of filtered belief revision and the above-mentioned set-theoretic structures, interpreted as semantic _partial_ belief revision structures. We also provide an interpretation of the trichotomous attitude towards information in terms of the degree of implausibility of the information. (shrink)

The theory of belief revision deals with (rational) changes in beliefs in response to new information. In the literature a distinction has been drawn between belief revision and belief update (see [6]). The former deals with situations where the objective facts describing the world do not change (so that only the beliefs of the agent change over time), while the letter allows for situations where both the facts and the doxastic state of the agent change over time. We focus on (...) belief revision and propose a temporal framework that allows for iterated revision. We model the notion of “minimal” or “conservative” belief revision by considering logics of increasing strength. We move from one logic to the next by adding one or more axioms and show that the corresponding logic captures more stringent notions of minimal belief revision. The strongest logic that we propose provides a full axiomatization of the well-known AGM theory of belief revision. (shrink)

Restricting attention to the class of extensive games defined by von Neumann and Morgenstern with the added assumption of perfect recall, we specify the information of each player at each node of the game-tree in a way which is coherent with the original information structure of the extensive form. We show that this approach provides a framework for a formal and rigorous treatment of questions of knowledge and common knowledge at every node of the tree. We construct a particular information (...) partition for each player and show that it captures the notion of maximum information in the sense that it is the finest within the class of information partitions that satisfy four natural properties. Using this notion of “maximum information” we are able to provide an alternative characterization of the meet of the information partitions. (shrink)

The Common Prior Assumption (CPA) plays an important role in game theory and the economics of information. It is the basic assumption behind decision-theoretic justifications of equilibrium reasoning in games (Aumann, 1987, Aumann and Brandenburger, 1995) and no-trade results with asymmetric information (Milgrom and Stokey, 1982). Recently several authors (Dekel and Gul, 1997, Gul, 1996, Lipman, 1995) have questioned whether the CPA is meaningful in situations of incomplete information, where there is no ex ante stage and where the primitives of (...) the model are the individuals' beliefs about the external world (their first-order beliefs), their beliefs about the other individuals' beliefs (second-order beliefs), etc., i.e. their hierarchies of beliefs. In this context, the CPA is a mathematical property whose conceptual content is not clear. The main results of this paper (Theorems 1 and 2) provide a characterization of Harsanyi consistency in terms of properties of the belief hierarchies that are entirely unrelated to the idea of an ex ante stage. (shrink)

An information completion of an extensive game is obtained by extending the information partition of every player from the set of her decision nodes to the set of all nodes. The extended partition satisfies Memory of Past Knowledge (MPK) if at any node a player remembers what she knew at earlier nodes. It is shown that MPK can be satisfied in a game if and only if the game is von Neumann (vN) and satisfies memory at decision nodes (the restriction (...) of MPK to a player's own decision nodes). A game is vN if any two decision nodes that belong to the same information set of a player have the same number of predecessors. By providing an axiom for MPK we also obtain a syntactic characterization of the said class of vN games. (shrink)