In 1933 Godel introduced a calculus of provability (also known as modal logic S4) and left open the question of its exact intended semantics. In this paper we give a solution to this problem. We find the logic LP of propositions and proofs and show that Godel's provability calculus is nothing but the forgetful projection of LP. This also achieves Godel's objective of defining intuitionistic propositional logic Int via classical proofs and provides a Brouwer-Heyting-Kolmogorov style provability semantics for Int which (...) resisted formalization since the early 1930s. LP may be regarded as a unified underlying structure for intuitionistic, modal logics, typed combinatory logic and λ-calculus. (shrink)

We compare the logic HYPE recently suggested by H. Leitgeb as a basic propositional logic to deal with hyperintensional contexts and Heyting-Ockham logic introduced in the course of studying logical aspects of the well-founded semantics for logic programs with negation. The semantics of Heyting-Ockham logic makes use of the so-called Routley star negation. It is shown how the Routley star negation can be obtained from Dimiter Vakarelov’s theory of negation and that propositional HYPE coincides with the logic characterized by the (...) class of all involutive Routley star information frames. This result provides a much simplified semantics for HYPE and also a simplified axiomatization, which shows that HYPE is identical with the modal symmetric propositional calculus introduced by G. Moisil in 1942. Moreover, it is shown that HYPE can be faithfully embedded into a normal bi-modal logic based on classical logic. Against this background, we discuss the notion of hyperintensionality. (shrink)

Here is an account of recent investigations into the two main concepts of negation developed in the constructive logic: the negation as reduction to absurdity, and the strong negation. These concepts are studied in the setting of paraconsistent logic.

ABSTRACT In 1933 Gödel introduced an axiomatic system, currently known as S4, for a logic of an absolute provability, i.e. not depending on the formalism chosen ([God 33]). The problem of finding a fair provability model for S4 was left open. The famous formal provability predicate which first appeared in the Gödel Incompleteness Theorem does not do this job: the logic of formal provability is not compatible with S4. As was discovered in [Art 95], this defect of the formal provability (...) predicate can be bypassed by replacing hidden quantifiers over proofs by proof polynomials in a certain finite basis. The resulting Logic of Proofs enjoys a natural arithmetical semantics and provides an intended provability model for S4, thus answering a question left open by Gödel in 1933. Proof polynomials give an intended semantics for some other constructions based on the concept of provability, including intuitionistic logic with its Brouwer- Heyting- Kolmogorov interpretation, ?-calculus and modal ?-calculus. In the current paper we demonstrate how the intuitionistic propositional logic Int can be directly realized by proof polynomials. It is shown, that Int is complete with respect to this proof realizability. (shrink)

This article examines a still contentious question: how conservative and liberal elements are combined in Boris N. Chicherin’s worldview and political doctrine. It considers several points of view...

Im Zentrum der Monographie von Claudia Rapp steht die Figur des christlichen Bischofs im Kontext der spätantiken Gesellschaft. Das Buch besteht aus zwei Teilen und einem Epilog. Der erste Teil (S. 1–152) erfüllt eine zweifache Aufgabe: Er bietet (1.) eine Übersicht über die relevante Forschungsliteratur und Positionierung der vorliegenden Arbeit in der Forschungslandschaft und (2.) die Präsentation des von der Verf. entworfenen Erklärungsmodells, das die gesamte Untersuchung konzeptuell bestimmt. Im zweiten Teil (S. 155–289) betrachtet die Verf. die Entwicklung der Rolle (...) des christlichen Bischofs im Kontext spätantiker Städte und Römischen Reiches vom 3. bis zum 6. Jahrhundert anhand von archäologischem, hagiographischem und juristischem Quellenmaterial. Im Epilog (S. 290–302) wird die Figur des Bischofs im Spiegel der Grabinschriften prominenter Amtsträger skizziert. Ein Quellen- und Literaturverzeichnis sowie ein Index beschließen den Band (S. 303–346). (shrink)

Uncertainty can’t be understood without taking into account both properties of the problem situation and agent’s knowledge about it. The correspondence of knowledge and situation of decision-making is crucial for understanding the onto-epistemological nature of uncertainty. At the same time, this correspondence is the key topic in virtue epistemology, especially in its ‘non-classical’, regulatory, branch, related to works of R. Roberts and W.J. Wood. In this article, genetic consultation is chosen as an example of such a problematic situation since a (...) doctor and a patient explicitly deal with the uncertainty of genetic risks. The problems of communication and joint decision-making in the context of medical-genetic consultation are comprehensively described in bioethics. At the same time, its social dimension is limited to the direct interaction of two individual agents, that allows us to use it as a model for constructing the ethics of uncertainty. In this article, four forms of uncertainty are identified: descriptive, normative and radical uncertainties, and translation uncertainty. Referring to the approaches of virtue epistemology, the author brings each of these forms into conformity with the proposed regulatory principle. The regulations assume that generating or disseminating knowledge under conditions of uncertainty require taking into account the incompleteness of the presented model of reality in its four aspects. A modelled fragment of reality could change in a predictable (descriptive uncertainty) or unexpected (radical uncertainty) way. The goals and values of a model’s user can not be hierarchically ordered, and may also change in the future (normative uncertainty). User’s interpretations of the model may be diverse, and can never be strictly defined by the intentions of the model’s author (indeterminancy of translation, or uncertainty whether success of co-reference is achieved). (shrink)

In this paper, we provide a semantic analysis of the well-known knowability paradox stemming from the Church–Fitch observation that the meaningful knowability principle /all truths are knowable/, when expressed as a bi-modal principle F --> K♢F, yields an unacceptable omniscience property /all truths are known/. We offer an alternative semantic proof of this fact independent of the Church–Fitch argument. This shows that the knowability paradox is not intrinsically related to the Church–Fitch proof, nor to the Moore sentence upon which it (...) relies, but rather to the knowability principle itself. Further, we show that, from a verifiability perspective, the knowability principle fails in the classical logic setting because it is missing the explicit incorporation of a hidden assumption of /stability/: ‘the proposition in question does not change from true to false in the process of discovery.’ Once stability is taken into account, the resulting /stable knowability principle/ and its nuanced versions more accurately represent verification-based knowability and do not yield omniscience. (shrink)

Tracing how the logic of inoperativity works in the domains of language, law, history and humanity, 'Agamben and Politics' systematically introduces the fundamental concepts of Agamben's political thought and a critically interprets his insights in the wider context of contemporary philosophy.

We outline an intuitionistic view of knowledge which maintains the original Brouwer–Heyting–Kolmogorov semantics for intuitionism and is consistent with the well-known approach that intuitionistic knowledge be regarded as the result of verification. We argue that on this view coreflectionA→KAis valid and the factivity of knowledge holds in the formKA→ ¬¬A‘known propositions cannot be false’.We show that the traditional form of factivityKA→Ais a distinctly classical principle which, liketertium non datur A∨ ¬A, does not hold intuitionistically, but, along with the whole of (...) classical epistemic logic, is intuitionistically valid in its double negation form ¬¬(KA¬A).Within the intuitionistic epistemic framework the knowability paradox is resolved in a constructive manner. We argue that this paradox is the result of an unwarranted classical reading of constructive principles and as such does not have the consequences for constructive foundations traditionally attributed it. (shrink)

Inspired by Hintikka’s ideas on constructivism, we are going to ‘effectivize’ the game-theoretic semantics for independence-friendly first-order logic, but in a somewhat different way than he did in the monograph ‘The Principles of Mathematics Revisited’. First we show that Nelson’s realizability interpretation—which extends the famous Kleene’s realizability interpretation by adding ‘strong negation’—restricted to the implication-free first-order formulas can be viewed as an effective version of GTS for FOL. Then we propose a realizability interpretation for IF-FOL, inspired by the so-called ‘trump (...) semantics’ which was discovered by Hodges, and show that this trump realizability interpretation can be viewed as an effective version of GTS for IF-FOL. Finally we prove that the trump realizability interpretation for IF-FOL appropriately generalises Nelson’s restricted realizability interpretation for the implication-free first-order formulas. (shrink)

The language of the basic logic of proofs extends the usual propositional language by forming sentences of the sort x is a proof of F for any sentence F. In this paper a complete axiomatization for the basic logic of proofs in Heyting Arithmetic HA was found.

The word “encyclopedia” comes to us from the Greek or, more precisely, is the deformed transcription, through Latin, of a erase in which we recognize a word composed of two elements, enkyklios and paideia, found in Quintilian in the ancient editions of De institutione oratoria (I, 10, 1). The expression itself, enkyklios paideia, appears only later, in the Hellenistic Age, under Roman domination, beginning with Dionysius of Halicarnassus (around the first century B.C.), but the concept goes back to the Eleatics, (...) especially to Hippias of Elis who, if we can believe the account in Plato's Dialogues, taught this total knowledge, later known with the term enkyklopaideia. (shrink)

Logical theories for representing knowledge are often plagued by the so-called Logical Omniscience Problem. The problem stems from the clash between the desire to model rational agents, which should be capable of simple logical inferences, and the fact that any logical inference, however complex, almost inevitably consists of inference steps that are simple enough. This contradiction points to the fruitlessness of trying to solve the Logical Omniscience Problem qualitatively if the rationality of agents is to be maintained. We provide a (...) quantitative solution to the problem compatible with the two important facets of the reasoning agent: rationality and resource boundedness. More precisely, we provide a test for the logical omniscience problem in a given formal theory of knowledge. The quantitative measures we use are inspired by the complexity theory. We illustrate our framework with a number of examples ranging from the traditional implicit representation of knowledge in modal logic to the language of justification logic, which is capable of spelling out the internal inference process. We use these examples to divide representations of knowledge into logically omniscient and not logically omniscient, thus trying to determine how much information about the reasoning process needs to be present in a theory to avoid logical omniscience. (shrink)

We describe a general logical framework, Justification Logic, for reasoning about epistemic justification. Justification Logic is based on classical propositional logic augmented by justification assertions t: F that read t is a justification for F. Justification Logic absorbs basic principles originating from both mainstream epistemology and the mathematical theory of proofs. It contributes to the studies of the well-known Justified True Belief vs. Knowledge problem. We state a general Correspondence Theorem showing that behind each epistemic modal logic, there is a (...) robust system of justifications. This renders a new, evidence-based foundation for epistemic logic. As a case study, we offer a resolution of the GoldmanRed Barns in Justification Logic. Furthermore, we formalize the well-known Gettier example and reveal hidden assumptions and redundancies in Gettier’s reasoning. (shrink)

This article addresses the relationship between ontology and politics in Jean-Luc Nancy’s theory of democracy by probing the implications of his latest ontological innovation, the concept of struction. We argue that Nancy’s democracy is a mode of politics that makes the radical pluralism of struction legitimate, opening and guarding a political space for the coexistence of the incommensurable. From this perspective, and despite Nancy’s own skepticism about the concept of biopolitics, the notion of struction opens a pathway for theorizing democracy (...) in a biopolitical key as the regime of coexistence of radically incommensurable forms of life in the absence of any coordinating principle. We nonetheless take issue with Nancy’s prescription for democracy to remain devoid of any political affirmation of its own. Instead, we suggest that the prescriptive content of democracy consists in the affirmation of the contingency of all the forms of life that coexist in it, which implies their freedom, equality, and comm... (shrink)

The article analyzes the philosophical concept of the “porous self” of J. Rivera. The originality of this concept in the post-phenomenological project is determined by the role of theological constructions that modify the primal experience of self-consciousness. This modification allows us to interpret the phenomenological description of the human self as different from the classical — “porous” temporality, i.e., correlating through “two entrances”—the internal and external—with eternity. Within this approach, the primary phenomenon of the constitution of the "porous" self becomes (...) the inner word, which in the appeal to eternity turns out to be the original self-awareness of the self as a temporality. The secondary phenomenon of the constitution of the “porous” self is not the mundane temporality of M. Heidegger, but Epektasis as an intense striving towards the end of time in General. The worldly temporality of the self, transformed by faith, is phenomenologically revealed as open to eternity in each of its moments. The third phenomenon of the temporality of the self is Memoria, whose interpretation reveals how the structure of the inner consciousness of time by E. Husserl can be framed ontologically and harmoniously integrated into the theological concept. The article shows how, based on this understanding of both the internal and external openness of the “porous” self for eternity, the integral structure of its temporality is formed. The temporality of the porous self is a modification of Husserl’s time diagrams and the intertwining of two streams of temporality at the same time from past to future and from future to past, which itself constitutes a phenomenal field of events of self. This understanding of temporality sets new perspectives for the phenomenological analysis of subjectivity. (shrink)

One of the main fields of consciousness studies is the search for the function of consciousness. The article deals with the hypothesis of the function of imagination as an attribute of consciousness. In the regard of the issues of the attributes of consciousness, the author analyzes the phenomenon of aphantasia, that is, lack of imagination. Despite the lack of formalized ideas about the function of consciousness and despite the scientific trend of the narrowing research areas where subjective experience is necessary (...) for a normal behavior of brain, there is a tendency to expand the presence of consciousness in the world in the modern Western philosophy of consciousness. The result of this “emancipation of consciousness” is the idea of the theoretical essential closeness of a human being and other agents: animals, artificial intelligence, plants. A consequence of the “emancipation of consciousness” is the emergence of modern versions of panpsychism, which propose expanding the space of consciousness to the world as a whole. However, studies in the field of conscious cognitive processes show that the processes that need the participation of consciousness, according to the standard intuitions, in some cases successfully performed without it. For example, the phenomenon of aphantasia shows that the tasks of imagination are performed in the absence of the ability to imagine. Therefore, it is important to take also into account the theoretical possibility of the lack of the realization of the function of consciousness. This makes it possible to ask a question about the presence of consciousness in the space that is traditionally endowed with consciousness, according to the dominant views in philosophy. Therefore, by approaching the question of the attributes of consciousness, the author demonstrates the limitations of the program for the emancipation of consciousness and offers an alternative solution to the question of the scale of the presence of consciousness in the world. (shrink)

Coercive subtyping offers a general approach to subtyping and inheritance by introducing a simple abbreviational mechanism to constructive type theories. In this paper, we study coercion completion in coercive subtyping and prove that the formal extension with coercive subtyping of a type theory such as Martin–Löf's type theory and UTT is a conservative extension. The importance of coherence conditions for the conservativity result is also discussed.

We shall be concerned with the modal logic BK—which is based on the Belnap–Dunn four-valued matrix, and can be viewed as being obtained from the least normal modal logic K by adding ‘strong negation’. Though all four values ‘truth’, ‘falsity’, ‘neither’ and ‘both’ are employed in its Kripke semantics, only the first two are expressible as terms. We show that expanding the original language of BK to include constants for ‘neither’ or/and ‘both’ leads to quite unexpected results. To be more (...) precise, adding one of these constants has the effect of eliminating the respective value at the level of BK-extensions. In particular, if one adds both of these, then the corresponding lattice of extensions turns out to be isomorphic to that of ordinary normal modal logics. (shrink)

Sergei Prozorov challenges the assumption that the biopolitical governance means the end of democracy, arguing for a positive synthesis of biopolitics and democracy. He develops a vision of democratic biopolitics where diverse forms of life can coexist on the basis of their reciprocal recognition as free, equal and in common.

'Ontological Semantics' introduces a comprehensive approach to the treatment of text meaning by computer, arguing that being able to use meaning is crucial to the success of natural language processing applications.

We define a realizability interpretation of Aczel's Constructive Set Theory CZF into Explicit Mathematics. The final results are that CZF extended by Mahlo principles is realizable in corresponding extensions of T 0 , thus providing relative lower bounds for the proof-theoretic strength of the latter.

The paper aims to present a critical analysis of the phenomenon and notion of exceptionalism in bioethics. The authors demonstrate that exceptionalism pertains to phenomena that are not (yet) entirely familiar to us and could potentially bear risks regarding their regulation. After an overview of the state of the art, we briefly describe the origins and evolution of the concept, compared to exception and exclusion. In the second step, they look at the overall development debates on genetic exceptionalism, compared to (...) other bioethical debates on exceptionalism, before presenting a detailed analysis of a specific case of early regulation of genetic screening. In the last part, the authors explain the historical background behind the connection between exceptionalism and exclusion in these debates. Their main conclusion is that while the initial stage of the discussion is shaped by the concept of exceptionalism and awareness of risks of exclusion, the later development centers around exceptions that are needed in detailed regulatory procedures. (shrink)

The present paper is devoted to computational aspects of propositional inconsistency-adaptive logics. In particular, we prove (relativized versions of) some principal results on computational complexity of derivability in such logics, namely in cases of CLuN r and CLuN m , i.e., CLuN supplied with the reliability strategy and the minimal abnormality strategy, respectively.

Byzantine intellectuals not only had direct access to Neoplatonic sources in the original language but also, at times, showed a particular interest in them. During the Early Byzantine period Platonism significantly contributed to the development of Christian doctrines and, paradoxically, remained a rival world view that was perceived by many Christian thinkers as a serious threat to their own intellectual identity. This problematic relationship was to become even more complex during the following centuries. Byzantine authors made numerous attempts to harmonize (...) Neoplatonic doctrines with Christianity as well as to criticize, refute and even condemn them. The papers assembled in this volume discuss a number of specific questions and concerns that drew the interest of Byzantine scholars in different periods towards Neoplatonic sources in an attempt to identify and explore the central issues in the reception of Neoplatonic texts during the Byzantine era. This is the first volume of the sub-series "Byzantinisches Archiv - Series Philosophica", which will be dedicated to the rapidly growing field of research in Byzantine philosophical texts. (shrink)

The publication of The Use of Bodies, the final volume in Giorgio Agamben’s Homo Sacer series, makes it possible to take stock of Agamben’s project as a whole. Having started with a powerful critique of the biopolitical sovereignty as the essence of modern politics, Agamben concludes his project with an affirmative vision of inoperative politics of form-of-life, in which life is not negated or sacrificed to the privileged form it must attain, but rather remains inseparable from the form that does (...) nothing but express it. The article begins by reconstituting the non-relational logic that Agamben develops in order to render inoperative the existing apparatuses of ontology, ethics and politics. We then address the dimension of lifestyle as a new key domain of Agamben’s work, in which biopolitics may be recast in an affirmative key of form-of-life. While Agamben is better known for sceptical and scornful statements about contemporary liberal democracies, we shall argue that his affirmative biopolitics, characterized by destituent power, resonates with Claude Lefort’s understanding of democracy as structured around the ontological void and epistemic indeterminacy. In the conclusion we question the viability of this biopolitical democracy, focusing on Agamben’s example of the Nocturnal Council in Plato’s Laws. (shrink)

The relationships between various modal logics based on Belnap and Dunn’s paraconsistent four-valued logic FDE are investigated. It is shown that the paraconsistent modal logic \, which lacks a primitive possibility operator \, is definitionally equivalent with the logic \, which has both \ and \ as primitive modalities. Next, a tableau calculus for the paraconsistent modal logic KN4 introduced by L. Goble is defined and used to show that KN4 is definitionally equivalent with \ without the absurdity constant. Moreover, (...) a tableau calculus is defined for the modal bilattice logic MBL introduced and investigated by A. Jung, U. Rivieccio, and R. Jansana. MBL is a generalization of BK that in its Kripke semantics makes use of a four-valued accessibility relation. It is shown that MBL can be faithfully embedded into the bimodal logic \ over the non-modal vocabulary of MBL. On the way from \ to MBL, the Fischer Servi-style modal logic \ is defined as the set of all modal formulas valid under a modified standard translation into first-order FDE, and \ is shown to be characterized by the class of all models for \. Moreover, \ is axiomatized and this axiom system is proved to be strongly sound and complete with respect to the class of models for \. Moreover, the notion of definitional equivalence is suitably weakened, so as to show that \ and \ are weakly definitionally equivalent. (shrink)

Pereboom and Caruso propose the quarantine model as an alternative to existing models of criminal justice. They appeal to the established public health practice of quarantining people, which is believed to be effective and morally justified, to explain why -in criminal justice- it is also morally acceptable to detain wrongdoers, without assuming the existence of a retrospective moral responsibility. Wrongdoers in their model are treated as carriers of dangerous diseases and as such should be preventively detained (or rehabilitated) until they (...) no longer pose a threat to society. Our main concern in this paper is that Pereboom and Caruso adopt an idiosyncratic meaning of quarantine regulations. We highlight a set of important disanalogies between their quarantine model and the quarantine regulations currently adopted in public health policies. More specifically, we argue that the similarities that Pereboom and Caruso propose to substantiate their analogy are not consistent—despite what they claim—with the regulations underlying quarantine as an epidemiological process. We also notice that certain quarantine procedures adopted in public health systems are inadequate to deal with criminal behaviors. On these grounds, we conclude that Pereboom and Caruso should not appeal to the quarantine analogy to substantiate their view, unless they address the issues and criticism we raise in this paper. (shrink)

We describe our explicit Lorentz-invariant solution of the Einstein and null geodesic equations for the deflection experiment of 2002 September 8 when a massive moving body, Jupiter, passed within 3.7’ of a line-of-sight to a distant quasar. We develop a general relativistic framework which shows that our measurement of the retarded position of a moving light-ray deflecting body (Jupiter) by making use of the gravitational time delay of quasar’s radio wave is equivalent to comparison of the relativistic laws of the (...) Lorentz transformation for gravity and light. Because, according to Einstein, the Lorentz transformation of gravity field variables must depend on a fundamental speed c, its measurement through the retarded position of Jupiter in the gravitational time delay allows us to study the causal nature of gravity and to set an upper limit on the speed of propagation of gravity in the near zone of the solar system as contrasted to the speed of the radio waves. In particular, the v/c term beyond of the standard Einstein’s deflection, which we measured to 20% accuracy, is associated with the aberration of the null direction of the gravity force (“aberration of gravity”) caused by the Lorentz transformation of the Christoffel symbols from the static frame of Jupiter to the moving frame of observer. General relativistic formulation of the experiment identifies the aberration of gravity with the retardation of gravity because the speed of gravitational waves in Einstein’s theory is equal to the speed of propagation of the gravity force. We discuss the misconceptions which have inhibited the acceptance of this interpretation of the experiment. We also comment on other interpretations of this experiment by Asada, Will, Samuel, Pascual–Sánchez, and Carlip and show that their “speed of light” interpretations confuse the Lorentz transformation for gravity with that for light, and the fundamental speed of gravity with the physical speed of light from the quasar. For this reason, the “speed of light” interpretations are not entirely consistent with a retarded Liénard–Wiechert solution of the Einstein equations, and do not properly incorporate how the phase of the radio waves from the quasar is perturbed by the retarded gravitational field of Jupiter. Although all of the formulations predict the same deflection to the order of v/c, our formulation shows that the underlying cause of this deflection term is associated with the aberration of gravity and not of light, and that the interpretations predict different deflections at higher orders of v/c beyond the Shapiro delay, thus, making their measurement highly desirable for deeper testing of general relativity in future astrometric experiments like Gaia, SIM, and SKA. (shrink)