The paper introduces a broad family of metrics applicable to finite and countably infinite strings, or, by extension, to formal structures serving as semantics for countable languages. The main focus is on applications to sets of pointed Kripke models, a semantics for modal logics. For the resulting metric spaces, the paper classifies topological properties including which metrics are topologically equivalent, providing sufficient conditions for compactness, characterizing clopen sets and isolated points, and characterizing the metrical topologies by a (...) concept of logical convergence. We then apply the approach to maps from dynamic epistemic logic, showing that product updates with action models yield continuous maps, hence allowing for an interpretation of the iterated updates as discrete time dynamical systems. (shrink)

The localic completion of a metric space induces a canonical notion of continuous map between metric spaces. It is shown that these maps are continuous in the sense of Bishop constructive mathematics, i.e., uniformly continuous near every compact image.

We show that the set of points of an overt closed subspace of a metric completion of a Bishop-locally compact metric space is located. Consequently, if the subspace is, moreover, compact, then its collection of points is Bishop-compact. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

As artificial intelligence (AI) deployment is growing exponentially, questions have been raised whether the developed AI ethics discourse is apt to address the currently pressing questions in the field. Building on critical theory, this article aims to expand the scope of AI ethics by arguing that in addition to ethical principles and design, the organizational dimension (i.e. the background assumptions and values influencing design processes) plays a pivotal role in the operationalization of ethics in AI development and deployment contexts. Through (...) the prism of critical theory, and the notions of underdetermination and technical code as developed by Feenberg in particular, the organizational dimension is related to two general challenges in operationalizing ethical principles in AI: (a) the challenge of ethical principles placing conflicting demands on an AI design that cannot be satisfied simultaneously, for which the term ‘inter-principle tension’ is coined, and (b) the challenge of translating an ethical principle to a technological form, constraint or demand, for which the term ‘intra-principle tension’ is coined. Rather than discussing principles, methods or metrics, the notion of technical code precipitates a discussion on the subsequent questions of value decisions, governance and procedural checks and balances. It is held that including and interrogating the organizational context in AI ethics approaches allows for a more in depth understanding of the current challenges concerning the formalization and implementation of ethical principles as well as of the ways in which these challenges could be met. (shrink)

Distributive justice deals with allocations of goods and bads within a group. Different principles and results of distributions are seen as possible ideals. Often those normative approaches are solely framed verbally, which complicates the application to different concrete distribution situations that are supposed to be evaluated in regard to justice. One possibility in order to frame this precisely and to allow for a fine-grained evaluation of justice lies in formal modelling of these ideals by metrics. Choosing a metric (...) that is supposed to map a certain ideal has to be justified. Such justification might be given by demanding specific substantiated axioms, which have to be met by a metric. This paper introduces such axioms for metrics of distributive justice shown by the example of needs-based justice. Furthermore, some exemplary metrics of needs-based justice and a three dimensional method for visualisation of non-comparative justice axioms or evaluations are presented. Therewith, a base worth discussing for the evaluation and modelling of metrics of distributive justice is given. (shrink)

Dwork, Hardt, Pitassi, Reingold, & Zemel [6] introduced two notions of fairness, each of which is meant to formalize the notion of similar treatment for similarly qualified individuals. The first of these notions, which we call additive metric fairness, has received much attention in subsequent work studying the fairness of a system composed of classifiers which are fair when considered in isolation [3, 4, 7, 8, 12] and in work studying the relationship between fair treatment of individuals and fair treatment (...) of groups [6, 7, 13]. Here, we extend these lines of research to the second, less-studied notion, which we call multiplicative metric fairness. In particular, we exactly characterize the fairness of conjunctions and disjunctions of multiplicative metric fair classifiers, and the extent to which a classifier which satisfies multiplicative metric fairness also treats groups fairly. This characterization reveals that whereas additive metric fairness becomes easier to satisfy when probabilities of acceptance are small, leading to unfairness under functional and group compositions, multiplicative metric fairness is better-behaved, due to its scale-invariance. (shrink)

The definition of a pseudofinite structure can be translated verbatim into continuous logic, but it also gives rise to a stronger notion and to two parallel concepts of pseudocompactness. Our purpose is to investigate the relationship between these four concepts and establish or refute each of them for several basic theories in continuous logic. Pseudofiniteness and pseudocompactness turn out to be equivalent for relational languages with constant symbols, and the four notions coincide with the standard pseudofiniteness in the case of (...) classical structures, but the details appear to be slightly more important here than in the usual translation of definitions from classical logic. We also prove that injective “formula-definable” endofunctions are surjective, and conversely, in strongly pseudofinite omega-saturated structures. (shrink)

We propose a novel framework that formalizes awareness within Relational Quantum Dynamics (RQD) by integrating Integrated Information Theory (IIT) with quantum measurement processes. In our approach, quantum interactions are not merely stochastic events, but are interpreted as intrinsic awareness updates that occur via Bayesian conditioning. Specifically, we define an awareness metric A(A : B) that combines the quantum mutual information generated during an interaction and Φ as a measure of integrated information. By modeling quantum measurements as stochastic processes and determinizing (...) these via outcome indexing, we construct a composite functor that maps probabilistic quantum instruments to deterministic awareness updates in a separate category of awareness states. We show that this functor preserves identities and composition, ensuring that multi-observer scenarios such as nested Wigner’s Friend or Frauchiger-Renner experiments produce a coherent alignment of facts once interactions occur, even though no single truth value exists prior to interaction. We outline experimental proposals, including nested observer experiments, gravitational entanglement tests, and the engineering of artificial observers with tunable integrated information, to test the predictions of our model. Our framework does not alter standard quantum mechanics but enriches its interpretation by positing that every quantum interaction is accompanied by an awareness update whose significance depends on both the amount of exchanged information and the integration capacity of the systems involved. This work provides a mathematically robust bridge between quantum foundations and cognitive science, suggesting that conscious experience may emerge naturally from the dynamics of quantum information. (shrink)

We propose a logic for reasoning about metric spaces with the induced topologies. It combines the 'qualitative' interior and closure operators with 'quantitative' operators 'somewhere in the sphere of radius r.' including or excluding the boundary. We supply the logic with both the intended metric space semantics and a natural relational semantics, and show that the latter (i) provides finite partial representations of (in general) infinite metric models and (ii) reduces the standard '∈-definitions' of closure and interior to simple constraints (...) on relations. These features of the relational semantics suggest a finite axiomatisation of the logic and provide means to prove its EXPTIME-completeness (even if the rational numerical parameters are coded in binary). An extension with metric variables satisfying linear rational (in)equalities is proved to be decidable as well. Our logic can be regarded as a 'well-behaved' common denominator of logical systems constructed in temporal, spatial, and similarity-based quantitative and qualitative representation and reasoning. Interpreted on the real line (with its Euclidean metric), it is a natural fragment of decidable temporal logics for specification and verification of real-time systems. On the real plane, it is closely related to quantitative and qualitative formalisms for spatial representation and reasoning, but this time the logic becomes undecidable. (shrink)

Hayes & MacEachern’s study of quatrain stanzas in English folk songs was the first application of stochastic Optimality Theory to a large corpus of data.1 It remains the most extensive study of versification that OT has to offer, and the most careful and perceptive formal analysis of folk song meter in any framework. In a follow-up study, Hayes concludes that stress and meter — or more generally, the prosodic structure of language and verse — are governed by separate constraint (...) systems which must be jointly satisfied by well-formed verse. Apart from its convincing arguments for a modular approach to metrics, it is notable for successfully implementing the analysis in OT, a framework whose parallelist commitments might seem philosophically at odds with modularity. (shrink)

Novelty is a key concept to understand creativity. Evaluating a piece of artwork or other creation in terms of novelty requires comparisons to other works and considerations about the elements that have been reused in the creative process. Human beings perform this analysis intuitively, but in order to simulate it using computers, the objects to be compared and the similarity metrics to be used should be formalized and explicitly implemented. In this paper we present a study on relevant elements (...) for the assessment of novelty in computer-generated narratives. We focus on the domain of folk-tales, working with simple plots and basic narrative elements: events, characters, props and scenarios. Based on the empirical results of this study we propose a set of computational metrics for the automatic assessment of novelty. Although oriented to the implementation of our own story generation system, the measurement methodology we propose can be easily generalized to other creative systems. (shrink)

We present a formal derivation of the Mino–Sasaki–Tanaka–Quinn–Wald (MSTQW) equation describing the self-force on a (semi-) classical relativistic point mass moving under the influence of quantized linear metric perturbations on a curved background space–time. The curvature of the space–time implies that the dynamics of the particle and the field is history-dependent and as such requires a non-equilibrium formalism to ensure the consistent evolution of both particle and field, viz., the worldline influence functional and the closed- time-path (CTP) coarse-grained effective (...) action. In the spirit of effective field theory, we regularize the formally divergent self-force by smearing the local part of the retarded Green’s function and employing a quasi-local expansion. We derive the MSTQW–Langevin equations describing the perturbations of the particle’s worldline about its semi-classical trajectory resulting from interactions with the quantum fluctuations of the linear metric perturbations. Finally, we demonstrate that the quantum fluctuations of the field could, in principle, leave imprints on gravitational waveforms expected to be observed by gravitational interferometers, thereby encoding information about tree-level perturbative quantum gravity. (shrink)

We study the decidability problem for metric and layered temporal logics. The logics we consider are suitable to model time granularity in various contexts, and they allow one to build granular temporal models by referring to the "natural scale" in any component of the model and by properly constraining the interactions between differently-grained components. A monadic second-order language combining operators such as temporal contextualization and projection, together with the usual displacement operator of metric temporal logics, is considered, and the theory (...) of finitely-layered metric temporal structures is shown to be decidable. (shrink)

This paper introduces a formal view of the semantics and pragmatics of corrective feedback in dialogues between adults and children. The goal of this research is to give a formal account of language coordination in dialogue, and semantic coordination in particular. Accounting for semantic coordination requires (1) a semantics, i.e. an architecture allowing for dynamic meanings and meaning updates as results of dialogue moves, and (2) a pragmatics, describing the dialogue moves involved in semantic coordination. We illustrate the (...) general approach by applying it to some examples from the literature on corrective feedback, and provide a fairly detailed discussion of one example using TTR (Type Theory with Records) to formalize concepts. TTR provides an analysis of linguistic content which is structured in order to allow modification and similarity metrics, and a framework for describing dialogue moves and resulting updates to linguistic resources. (shrink)

For a locally compact group G, we show that it is possible to present the class of continuous unitary representations of G as an elementary class of metric structures, in the sense of continuous logic. More precisely, we show how nondegenerate ∗-representations of a general ∗-algebra A (with some mild assumptions) can be viewed as an elementary class, in a many-sorted language, and use the correspondence between continuous unitary representations of G and nondegenerate ∗-representations of L1(G). We relate the notion (...) of ultraproduct of logical structures, under this presentation, with other notions of ultraproduct of representations appearing in the literature, and we characterize property (T) for G in terms of the definability of the sets of fixed points of L1 functions on G. (shrink)

This monograph aims to mathematically codify the notion of "moral systems" and define a sensible distance between them. It consists of three parts, aimed at an audience with varying interests and mathematical backgrounds. The first part steers philosophical, formally defining moral systems and several related concepts. The second part studies black box algorithms, including questions of inference and metric construction. The third part explores the technical construction of metrics amongst conditional probability distributions.

We show that the formulations of non-relativistic quantum mechanics can be derived from an extended least action principle. The principle can be considered as an extension of the least action principle from classical mechanics by factoring in two assumptions. First, the Planck constant defines the minimal amount of action a physical system needs to exhibit during its dynamics in order to be observable. Second, there is constant vacuum fluctuation along a classical trajectory. A novel method is introduced to define the (...) information metrics to measure additional observability due to vacuum fluctuations, which is then converted to an additional action through the first assumption. Applying the variational principle to minimize the total actions allows us to recover the basic quantum formulations including the uncertainty relation and the Schrödinger equation in the position representation. In the momentum representation, the same method can be applied to obtain the Schrödinger equation for a free particle while further investigation is still needed for a particle with an external potential. Furthermore, the principle brings in new results on two fronts. At the conceptual level, we find that the information metrics for vacuum fluctuations are responsible for the origin of the Bohm quantum potential. Even though the Bohm potential for a bipartite system is inseparable, the underlying vacuum fluctuations are local. Thus, inseparability of the Bohm potential does not justify a non-local causal relation between the two subsystems. At the mathematical level, quantifying the information metrics for vacuum fluctuations using more general definitions of relative entropy results in a generalized Schrödinger equation that depends on the order of relative entropy. The extended least action principle is a new mathematical tool. It can be applied to derive other quantum formalisms such as quantum scalar field theory. (shrink)

Relational complexity provides a metric for measuring task demands, and in this respect has much in common with the cognitive complexity and control theory. However, relational complexity does not account for the relative difficulty of different relational types, and appears to underestimate the importance of changes in children's ability to act on the basis of their understanding.

ABSTRACT This article distinguishes nine senses of polarization and provides formal measures for each one to refine the methodology used to describe polarization in distributions of attitudes. Each distinct concept is explained through a definition, formal measures, examples, and references. We then apply these measures to GSS data regarding political views, opinions on abortion, and religiosity—topics described as revealing social polarization. Previous breakdowns of polarization include domain-specific assumptions and focus on a subset of the distribution’s features. This has (...) conflated multiple, independent features of attitude distributions. The current work aims to extract the distinct senses of polarization and demonstrate that by becoming clearer on these distinctions we can better focus our efforts on substantive issues in social phenomena. (shrink)

In a previous paper we constructed a full and faithful functor ℳ from the category of locally compact metric spaces to the category of formal topologies . Here we show that for a real-valued continuous function f, ℳ factors through the localic positive reals if, and only if, f has a uniform positive lower bound on each ball in the locally compact space. We work within the framework of Bishop constructive mathematics, where the latter notion is strictly stronger than (...) point-wise positivity. (shrink)

Many formalisms for reasoning about knowing commit an agent to be logically omniscient. Logical omniscience is an unrealistic principle for us to use to build a real-world agent, since it commits the agent to knowing infinitely many things. A number of formalizations of knowledge have been developed that do not ascribe logical omniscience to agents. With few exceptions, these approaches are modifications of the possible-worlds semantics. In this paper we use a combination of several general techniques for building non-omniscient reasoners. (...) First we provide for the explicit representation of notions such as problems, solutions, and problem solving activities, notions which are usually left implicit in the discussions of autonomous agents. A second technique is to take explicitly into account the notion of resource when we formalize reasoning principles. We use the notion of resource to describe interesting principles of reasoning that are used for ascribing knowledge to agents. For us, resources are abstract objects. We make extensive use of ordering and inaccessibility relations on resources, but we do not find it necessary to define a metric. Using principles about resources without using a metric is one of the strengths of our approach.We describe the architecture of a reasoner, built from a finite number of components, who solves a puzzle, involving reasoning about knowing, by explicitly using the notion of resource. Our approach allows the use of axioms about belief ordinarily used in problem solving – such as axiom K of modal logic – without being forced to attribute logical omniscience to any agent. In particular we address the issue of how we can use resource-unbounded (e.g., logically omniscient) reasoning to attribute knowledge to others without introducing contradictions. We do this by showing how omniscient reasoning can be introduced as a conservative extension over resource-bounded reasoning. (shrink)

Formal spaces have become commonplace conceptual and computational tools in a large array of scientific disciplines, including both the natural and the social sciences. Morphological spaces are spaces describing and relating organismal phenotypes. They play a central role in morphometrics, the statistical description of biological forms, but also underlie the notion of adaptive landscapes that drives many theoretical considerations in evolutionary biology. We briefly review the topological and geometrical properties of the most common morphospaces in the biological literature. In (...) contemporary geometric morphometrics, the notion of a morphospace is based on the Euclidean tangent space to Kendall’s shape space, which is a Riemannian manifold. Many more classical morphospaces, such as Raup’s space of coiled shells, lack these metric properties, e.g., due to incommensurably scaled variables, so that these morphospaces typically are affine vector spaces. Other notions of a morphospace, like Thomas and Reif’s skeleton space, may not give rise to a quantitative measure of similarity at all. Such spaces can often be characterized in terms of topological or pretopological spaces. (shrink)

This paper gives a formalization of general topology in second-order arithmetic using countably based MF spaces. This formalization is used to study the reverse mathematics of general topology. For each poset P we let MF denote the set of maximal filters on P endowed with the topology generated by {Np | p ∈ P}, where Np = {F ∈ MF | p ∈ F}. We define a countably based MF space to be a space of the form MF for some (...) countable poset P. The class of countably based MF spaces includes all complete separable metric spaces as well as many nonmetrizable spaces. The following reverse mathematics results are obtained. The proposition that every nonempty Gδ subset of a countably based MF space is homeomorphic to a countably based MF space is equivalent to [Formula: see text] over ACA0. The proposition that every uncountable closed subset of a countably based MF space contains a perfect set is equivalent over [Formula: see text] to the proposition that [Formula: see text] is countable for all A ⊆ ℕ. The proposition that every regular countably based MF space is homeomorphic to a complete separable metric space is equivalent to [Formula: see text] over [Formula: see text]. (shrink)

We develop measure theory in the context of subsystems of second order arithmetic with restricted induction. We introduce a combinatorial principleWWKL (weak-weak König's lemma) and prove that it is strictly weaker thanWKL (weak König's lemma). We show thatWWKL is equivalent to a formal version of the statement that Lebesgue measure is countably additive on open sets. We also show thatWWKL is equivalent to a formal version of the statement that any Borel measure on a compact metric space is (...) countably additive on open sets. (shrink)

A word-by-word human sentence processing complexity metric is presented. This metric formalizes the intuition that comprehenders have more trouble on words contributing larger amounts of information about the syntactic structure of the sentence as a whole. The formalization is in terms of the conditional entropy of grammatical continuations, given the words that have been heard so far. To calculate the predictions of this metric, Wilson and Carroll's (1954) original entropy reduction idea is extended to infinite languages. This is demonstrated with (...) a mildly context-sensitive language that includes relative clauses formed on a variety of grammatical relations across the Accessibility Hierarchy of Keenan and Comrie (1977). Predictions are derived that correlate significantly with repetition accuracy results obtained in a sentence-memory experiment (Keenan & Hawkins, 1987). (shrink)

Since the February 2020 publication of the article ‘Flattening the curve’ in The Economist, political leaders worldwide have used this expression to legitimize the introduction of social distancing measures in fighting Covid-19. In fact, this expression represents a complex combination of three components: the shape of the epidemic curve, the social distancing measures and the reproduction number \. Each component has its own history, each with a different history of control. Presenting the control of the epidemic as flattening the curve (...) is in fact flattening the underlying natural-social complexity. The curve that needs to be flattened is presented as a bell-shaped curve, implicitly suggesting that the pathogen’s spread is subject only to natural laws. The \ value, however, is, fundamentally, a metric of how a pathogen behaves within a social context, namely its numerical value is affected by sociopolitical influences. The jagged and erratic empirical curve of Covid-19 illustrates this. Although the virus has most likely infected only a small portion of the total susceptible population, it is clear its shape has changed drastically. This changing shape is largely due to sociopolitical factors. These include shifting formal laws and policies, shifting individual behaviors as well as shifting various other social norms and practices. This makes the course of Covid-19 curve both erratic and unpredictable. (shrink)

Dini's theorem says that compactness of the domain, a metric space, ensures the uniform convergence of every simply convergent monotone sequence of real-valued continuous functions whose limit is continuous. By showing that Dini's theorem is equivalent to Brouwer's fan theorem for detachable bars, we provide Dini's theorem with a classification in the recently established constructive reverse mathematics propagated by Ishihara. As a complement, Dini's theorem is proved to be equivalent to the analogue of the fan theorem, weak König's lemma, in (...) the original classical setting of reverse mathematics started by Friedman and Simpson. (shrink)

Social transmission is at the core of cultural evolutionary theory. It occurs when a demonstrator uses mental representations to produce some public displays which in turn allow a learner to acquire similar mental representations. Although cultural evolutionists do not dispute this view of social transmission, they typically abstract away from the multistep nature of the process when they speak of cultural variants at large, thereby referring both to variation and evolutionary change in mental representations as well as in their corresponding (...) public displays. This conflation suggests that differentiating each step of the transmission process is redundant. In this paper, I examine different forms of interplay between the multistep nature of social transmission and the metric spaces used by cultural evolutionists to measure cultural variation and to model cultural change. I offer a conceptual analysis of what assumptions seem to be at work when cultural evolutionists conflate the complex causal sequence of social transmission as a single space of variation in which populations evolve. To this aim, I use the framework of variation spaces, a formal framework commonly used in evolutionary biology, and I develop two theoretical concepts, ‘technique’ and ‘technical space’, for addressing cases where the complexity of social transmission defies the handy assumption of a single variation space for cultural change. (shrink)

The paper analyses the formal features of the characters of Oresteia in Greek tragedy. The protagonists and the minor characters are compared, for which the rhythmical liveliness and variability of the personages’ utterances, the length and number of utterances, and the number of dialogue verses in the metrical repertoire of the corresponding personage are taken into account. The analysis revealed that the data of Sophocles and Euripides are more close to each other both in the respect of general “liveliness” (...) and the “liveliness” of characters’ utterances. Certain differences in the metrics and rhythmics of the main and minor characters’ verses become most obvious when we compare Electra’s part with minor characters (e. g., in Electra’s part there is always the biggest proportion of lyrical parts, more unstandard settlements, more verses with splits than any other character). The index of liveliness of Electra’s part is almost the same in all the authors. Although the same tendencies in Orestes are more schematical, the metrics and rhythmics of his utterances are rather similar to those of Electra. Thus, in respect of the proportion of lyrical verses, he always comes second after Electra; he also has quite many split verses. The parts of minor characters are usually made up entirely of iambic trimesters, the rhythmical variety of their speeches is higher than average, but there are no splits in their parts (except for Aegisthus). However, there are characters which parts have unstandard rhythm, e.g., the pedagogue in Sophocles or Chrysothemis, who is a contrast to Electra by her nature as well as her rhythmics. The contrast with other minor characters is even bigger. Clytaemnestra’s part is both rhythmically and metrically intermediate: inAeschylus her utterances consist entirely of iambic trimeters, but in Sophocles and Euripides she pronounces also a couple of lyrical verses. There are alsosome splits in her verses which usually do not occur in minor persons. (shrink)

We show that in the Gromov space of isometry classes of pointed proper metric spaces, the equivalence relations defined by existence of coarse quasi-isometries or being at finite Gromov–Hausdorff distance cannot be reduced to the equivalence relation defined by any Polish action.

We use the system of p-adic numbers for the description of information processes. Basic objects of our models are so-called transformers of information, basic processes are information processes and statistics are information statistics (thus we present a model of information reality). The classical and quantum mechanical formalisms on information p-adic spaces are developed. It seems that classical and quantum mechanical models on p-adic information spaces can be applied for the investigation of flows of information in cognitive and social systems, since (...) a p-adic metric gives a quite natural description of the ability to form associations. (shrink)

Following a previous article published in Biological Theory, in this study we present a mathematical theory for a science of qualities as directly perceived by living organisms, and based on morphological patterns. We address a range of qualitative phenomena as observables of a psychological system seen as an impredicative system. The starting point of our study is the notion that perceptual phenomena are projections of underlying invariants, objects that remain unchanged when transformations of a certain class under consideration are applied. (...) The study develops with the observables, the entailed total order and metric, whence the algebra and the geometry of such a science, presenting a formal phenomenological model for phenomena that are not rigidly Euclidean. We show how non-Euclidean perception can have many useful Euclidean formalizations, as well as locally-homeomorphic-to-Euclidean-space models. The mathematical models we provide are tested on the basis of results from experimental psychology, in particular from the field of color, time, and space perception. (shrink)

A possible way out of the conundrum of quantum gravity is the proposal that general relativity (GR) emerges from an underlying microscopic description. Despite recent interest in the emergent gravity program within the physics as well as the philosophy community, an assessment of the general motivation for this idea is lacking at the moment. We intend to fill this gap in the literature by discussing the main arguments in favour of the hypothesis that the metric field and its dynamics are (...) emergent. First, we distinguish between microstructure inspired from GR, such as through quantization or discretization, and microstructure that is not directly motivated from GR, such as strings, quantum bits or condensed matter fields. The emergent gravity approach can then be defined as the view that the metric field and its dynamics are derivable from the latter type of microstructure. Subsequently, we assess in how far the following properties of (semi-classical) GR are suggestive of underlying microstructure: (1) the metric's universal coupling to matter fields, (2) perturbative non-renormalizability, (3) black hole thermodynamics, and (4) the holographic principle. In the conclusion we formalize the general structure of the plausibility arguments put forward. (shrink)

This paper assumes the success of arguments against the view that informal mathematical proofs secure rational conviction in virtue of their relations with corresponding formal derivations. This assumption entails a need for an alternative account of the logic of informal mathematical proofs. Following examination of case studies by Manders, De Toffoli and Giardino, Leitgeb, Feferman and others, this paper proposes a framework for analysing those informal proofs that appeal to the perception or modification of diagrams or to the inspection (...) or imaginative manipulation of mental models of mathematical phenomena. Proofs relying on diagrams can be rigorous if it is easy to draw a diagram that shares or otherwise indicates the structure of the mathematical object, the information thus displayed is not metrical and it is possible to put the inferences into systematic mathematical relation with other mathematical inferential practices. Proofs that appeal to mental models can be rigorous if the mental models can be externalised as diagrammatic practice that satisfies these three conditions. (shrink)

‘It is supposed’, declared the poet Wordsworth in 1802, ‘that by the act of writing in verse an author makes a formal engagement that he will gratify certain known habits of association; that he not only thus apprizes the reader that certain classes of ideas and expressions will be found in his book, but that others will be carefully excluded. This exponent or symbol held forth by metrical language must in different eras of literature have excited very different expectations.’ (...) For his own era of literature Wordsworth proposed a language derived from the ‘simple and unelaborated expressions’ of the ‘language really spoken by men’, at the expense of ‘devices to elevate the style’ and ‘what is usually called poetic diction’. (shrink)

We carry out a systematic study of decidability for theories of real vector spaces, inner product spaces, and Hilbert spaces and of normed spaces, Banach spaces and metric spaces, all formalized using a 2-sorted first-order language. The theories for list turn out to be decidable while the theories for list are not even arithmetical: the theory of 2-dimensional Banach spaces, for example, has the same many-one degree as the set of truths of second-order arithmetic.We find that the purely universal and (...) purely existential fragments of the theory of normed spaces are decidable, as is the ∀∃ fragment of the theory of metric spaces. These results are sharp of their type: reductions of Hilbertʼs 10th problem show that the ∃∀ fragments for metric and normed spaces and the ∀∃ fragment for normed spaces are all undecidable. (shrink)

One can use mathematics not as an instrument or measure, or a replacement for God, but as a poetic articulation, or perhaps as a stammered experimental approach to cultural dynamics. I choose to start with the simplest symbolic substances that respect the lifeworld’s continuous dynamism, temporality, boundless morphogenesis, superposability, continuity, density and value, and yet are independent of measure, metric, counting, finitude, formal logic, syntax, grammar, digitality and computability – in short, free of the formal structures that would (...) put a cage over all of the lifeworld. I call these substances topological media. This article introduces elementary topological concepts with which we can articulate material and cultural change using notions of proximity, limit, and change, without recourse to number or metric. The motivation is that topology furnishes us with concepts well-adapted for poietically articulating the world as stuff, rather than objects with an a priori schema. With care, it may provide a fruitful approach to morphogenesis and cultural dynamics that is neither reductive nor anthropocentric. I will not pretend any systematic application of the scaffolding concepts introduced in this article. Instead, I would see what fellow students of cultural dynamics and cosmopolitics make of these concepts in their own work. (shrink)

A new calculus, based upon the multivector derivative, is developed for Lagrangian mechanics and field theory, providing streamlined and rigorous derivations of the Euler-Lagrange equations. A more general form of Noether's theorem is found which is appropriate to both discrete and continuous symmetries. This is used to find the conjugate currents of the Dirac theory, where it improves on techniques previously used for analyses of local observables. General formulas for the canonical stress-energy and angular-momentum tensors are derived, with spinors and (...) vectors treated in a unified way. It is demonstrated that the antisymmetric terms in the stress-energy tensor are crucial to the correct treatment of angular momentum. The multivector derivative is extended to provide a functional calculus for linear functions which is more compact and more powerful than previous formalisms. This is demonstrated in a reformulation of the functional derivative with respect to the metric, which is then used to recover the full canonical stress-energy tensor. Unlike conventional formalisms, which result in a symmetric stress-energy tensor, our reformulation retains the potentially important antisymmetric contribution. (shrink)

The article studies knowledge in multiagent systems where data available to the agents may have small errors. To reason about such uncertain knowledge, a formal semantics is introduced in which indistinguishability relations, commonly used in the semantics for epistemic logic S5, are replaced with metrics to capture how much two epistemic worlds are different from an agent’s point of view. The main result is a logical system sound and complete with respect to the proposed semantics.

Gödel's Philosophical Legacy Kurt Gödel's contributions to philosophy extend beyond his incompleteness theorems. He engaged deeply with the work of other philosophers, including Immanuel Kant and Edmund Husserl, and explored topics such as the nature of time, the structure of the universe, and the relationship between mathematics and reality. Gödel's philosophical writings, though less well-known than his mathematical work, offer rich insights into his views on the nature of existence, the limits of human knowledge, and the interplay between the finite (...) and the infinite. His work continues to inspire and challenge philosophers, mathematicians, and scientists, inviting them to explore the profound and often enigmatic questions at the heart of human understanding. -/- Kurt Gödel's Broader Contributions to Philosophy Kurt Gödel, while primarily known for his monumental incompleteness theorems, made significant contributions that extended beyond the realm of mathematical logic. His philosophical pursuits deeply engaged with the works of eminent philosophers like Immanuel Kant and Edmund Husserl. Gödel's explorations into the nature of time, the structure of the universe, and the relationship between mathematics and reality reveal a profound and multifaceted intellectual legacy. -/- Engagement with Immanuel Kant Gödel held a deep interest in the philosophy of Immanuel Kant. He admired Kant's critical philosophy, particularly the distinction between the noumenal and phenomenal worlds. Kant posited that human experience is shaped by the mind’s inherent structures, leading to the conclusion that certain aspects of reality (the noumenal world) are fundamentally unknowable. Gödel’s incompleteness theorems echoed this Kantian theme, illustrating the limits of formal systems in capturing the totality of mathematical truth. Gödel believed that mathematical truths exis t independently of human thought, akin to Kant's noumenal realm. This philosophical alignment provided a robust foundation for Gödel's Platonism, which asserted the existence of mathematical objects as real, albeit abstract, entities. -/- Influence of Edmund Husserl Gödel was also profoundly influenced by Edmund Husserl, the founder of phenomenology. Husserl's phenomenology emphasizes the direct investigation and description of phenomena as consciously experienced, without preconceived theories about their causal explanation. Gödel saw Husserl's work as a pathway to bridge the gap between the abstract world of mathematics and concrete human experience. Husserl's ideas about the structures of consciousness and the intentionality of thought resonated with Gödel's views on mathematical intuition. Gödel believed that human minds could access mathematical truths through intuition, a concept that draws on Husserlian phenomenological methods. -/- The Nature of Time and the Universe Gödel's philosophical inquiries extended to the nature of time and the structure of the universe. His collaboration with Albert Einstein at the Institute for Advanced Study led to the development of the "Gödel metric" in 1949. This solution to Einstein's field equations of general relativity described a rotating universe where time travel to the past was theoretically possible. Gödel's model challenged conventional notions of time and causality, suggesting that the universe might have a more intricate structure than previously thought. Gödel's exploration of time was not just a mathematical curiosity but a profound philosophical statement about the nature of reality. He questioned whether time was an objective feature of the universe or a construct of human consciousness. His work hinted at a timeless realm of mathematical truths, aligning with his Platonist view. -/- Mathematics and Reality Gödel's philosophical outlook extended to the broader relationship between mathematics and reality. He believed that mathematics provided a more profound insight into the nature of reality than empirical science. For Gödel, mathematical truths were timeless and unchangeable, existing independently of human cognition. This perspective led Gödel to critique the materialist and mechanistic views that dominated 20th-century science and philosophy. He argued that a purely physicalist interpretation of the universe failed to account for the existence of abstract mathematical objects and the human capacity to understand them. Gödel's philosophy suggested a more integrated view of reality, where both physical and abstract realms coexist and inform each other. -/- Gödel's Exploration of Time Kurt Gödel, one of the most profound logicians of the 20th century, ventured beyond the confines of mathematical logic to explore the nature of time. His inquiries into the concept of time were not merely theoretical musings but were grounded in rigorous mathematical formulations. Gödel's exploration of time challenged conventional views and opened new avenues of thought in both physics and philosophy. -/- Gödel and Einstein Gödel’s interest in the nature of time was significantly influenced by his friendship with Albert Einstein. Both were faculty members at the Institute for Advanced Study in Princeton, where they engaged in deep discussions about the nature of reality, time, and space. Gödel's exploration of time culminated in his solution to Einstein's field equations of general relativity, known as the Gödel metric. -/- The Gödel Metric In 1949, Gödel presented a model of a rotating universe, which became known as the Gödel metric. This solution to the equations of general relativity depicted a universe where time travel to the past was theoretically possible. Gödel’s rotating universe contained closed timelike curves (CTCs), paths in spacetime that loop back on themselves, allowing for the possibility of traveling back in time. The Gödel metric posed a significant philosophical challenge to the conventional understanding of time. If time travel were possible, it would imply that time is not linear and absolute, as commonly perceived, but rather malleable and subject to the geometry of spacetime. This raised profound questions about causality, the nature of temporal succession, and the very structure of reality. -/- Philosophical Implications Gödel’s exploration of time extended beyond the mathematical implications to broader philosophical inquiries: Nature of Time: Gödel questioned whether time was an objective feature of the universe or a construct of human consciousness. His work suggested that our understanding of time as a linear progression from past to present to future might be an illusion, shaped by the limitations of human perception. -/- Causality and Free Will: The existence of closed timelike curves in Gödel’s model raised questions about causality and free will. If one could travel back in time, it would imply that future events could influence the past, potentially leading to paradoxes and challenging the notion of a deterministic universe. -/- Temporal Ontology: Gödel's work contributed to debates in temporal ontology, particularly the debate between presentism (the view that only the present exists) and eternalism (the view that past, present, and future all equally exist). Gödel’s rotating universe model seemed to support eternalism, suggesting a block universe where all points in time are equally real. Philosophy of Science: Gödel’s exploration of time had implications for the philosophy of science, particularly in the context of understanding the limits of scientific theories. His work underscored the importance of considering philosophical questions when developing scientific theories, as they shape our fundamental understanding of concepts like time and space. -/- Legacy Gödel’s exploration of time remains a significant and controversial contribution to both physics and philosophy. His work challenged established notions and encouraged deeper inquiries into the nature of reality. Gödel’s rotating universe model continues to be a topic of interest in theoretical physics and cosmology, inspiring new research into the nature of time and the possibility of time travel. In philosophy, Gödel’s inquiries into time have prompted ongoing debates about the nature of temporal reality, the relationship between mathematics and physical phenomena, and the limits of human understanding. His work exemplifies the intersection of mathematical rigor and philosophical inquiry, demonstrating the profound insights that can emerge from such an interdisciplinary approach. The Temporal Ontology of Kurt Gödel Kurt Gödel's profound contributions to mathematics and logic extend into the realm of temporal ontology—the philosophical study of the nature of time and its properties. Gödel's insights challenge conventional perceptions of time and suggest a more intricate, layered understanding of temporal reality. This essay explores Gödel's contributions to temporal ontology, particularly through his engagement with relativity and his philosophical reflections. -/- Gödel's Rotating Universe One of Gödel’s most notable contributions to temporal ontology comes from his work in cosmology, specifically his solution to Einstein’s field equations of general relativity, known as the Gödel metric. Introduced in 1949, the Gödel metric describes a rotating universe with closed timelike curves (CTCs). These curves imply that, in such a universe, time travel to the past is theoretically possible, presenting a significant challenge to conventional views of linear, unidirectional time. -/- Implica tions for Temporal Ontology Gödel's rotating universe model has profound implications for our understanding of time: Eternalism vs. Presentism: Gödel’s model supports the philosophical stance known as eternalism, which posits that past, present, and future events are equally real. In contrast to presentism, which holds that only the present moment exists, eternalism suggests a "block universe" where time is another dimension like space. Gödel’s rotating universe, with its CTCs, reinforces this view by demonstrating that all points in time could, in principle, be interconnected in a consistent manner. Non-linearity of Time: The possibility of closed timelike curves challenges the idea of time as a linear sequence of events. In Gödel’s universe, time is not merely a straight path from past to future but can loop back on itself, allowing for complex interactions between different temporal moments. This non-linearity has implications for our understanding of causality and the nature of temporal succession. Objective vs. Subjective Time: Gödel’s work invites reflection on the distinction between objective time (the time that exists independently of human perception) and subjective time (the time as experienced by individuals). His model suggests that our subjective experience of a linear flow of time may not correspond to the objective structure of the universe. This raises questions about the relationship between human consciousness and the underlying temporal reality. -/- Gödel and Philosophical Reflections on Time Gödel’s engagement with temporal ontology was not limited to his cosmological work. He also reflected deeply on philosophical questions about the nature of time and reality, drawing on the ideas of other philosophers and integrating them into his own thinking. Kantian Influences: Gödel was influenced by Immanuel Kant’s distinction between the noumenal world (things as they are in themselves) and the phenomenal world (things as they appear to human observers). Gödel’s views on time echoed this distinction, suggesting that our perception of time might be a phenomenon shaped by the limitations of human cognition, while the true nature of time (the noumenal aspect) might be far more complex and non-linear. Husserlian Phenomenology: Gödel’s interest in Edmund Husserl’s phenomenology also informed his views on time. Husserl’s emphasis on the structures of consciousness and the intentionality of thought resonated with Gödel’s belief in the importance of intuition in accessing mathematical truths. Gödel’s reflections on time incorporated a phenomenological perspective, considering how temporal experience is structured by human consciousness. Mathematical Platonism: Gödel’s Platonist views extended to his understanding of time. Just as he believed in the independent existence of mathematical objects, Gödel saw time as an objective entity with a structure that transcends human perception. His work on the Gödel metric can be seen as an attempt to uncover this objective structure, revealing the deeper realities that underlie our experience of time. (shrink)

Locatedness is one of the fundamental notions in constructive mathematics. The existence of a positivity predicate on a locale, i.e. the locale being overt, or open, has proved to be fundamental in constructive locale theory. We show that the two notions are intimately connected.Bishop defines a metric space to be compact if it is complete and totally bounded. A subset of a totally bounded set is again totally bounded iff it is located. So a closed subset of a Bishop compact (...) set is Bishop compact iff it is located. We translate this result to formal topology. ‘Bishop compact’ is translated as compact and overt. We propose a definition of locatedness on subspaces of a formal topology, and prove that a closed subspace of a compact regular formal space is located iff it is overt. Moreover, a Bishop-closed subset of a complete metric space is Bishop compact — that is, totally bounded and complete — iff its localic completion is compact overt.Finally, we show by elementary methods that the points of the Vietoris locale of a compact regular locale are precisely its compact overt sublocales.We work constructively, predicatively and avoid the use of the axiom of countable choice. (shrink)

Language and culture endow humans with access to conceptual information that far exceeds any which could be accessed by a non-human animal. Yet, it is possible that, even without language or specific experiences, non-human animals represent and infer some aspects of similarity relations between objects in the same way as humans. Here, we show that monkeys’ discrimination sensitivity when identifying images of animals is predicted by established measures of semantic similarity derived from human conceptual judgments. We used metrics from (...) computer vision and computational neuroscience to show that monkeys’ and humans’ performance cannot be explained by low-level visual similarity alone. The results demonstrate that at least some of the underlying structure of object representations in humans is shared with non-human primates, at an abstract level that extends beyond low-level visual similarity. Because the monkeys had no experience with the objects we tested, the results suggest that monkeys and humans share a primitive representation of object similarity that is independent of formal knowledge and cultural experience, and likely derived from common evolutionary constraints on object representation. (shrink)

We introduce _Interleave-Disjunction-Lock parallel multiple context-free grammars_ (IDL-PMCFG), a novel grammar formalism designed to describe the syntax of free word order languages that allow for extensive interleaving of grammatical constituents. Though interleaved constituents, and especially the so-called hyperbaton, are common in several ancient (Classical Latin and Greek, Sanskrit...) and modern (Hungarian, Finnish...) languages, these syntactic structures are often difficult to express in existing formalisms. The IDL-PMCFG formalism combines Seki et al.’s parallel multiple context-free grammars (PMCFG) with Nederhof and Satta’s IDL (...) expressions. We define the semantics of IDL-PMCFGs and study their expressivity, proving that IDL-PMCFG extends both PMCFG and IDL-CFG (context-free grammars equipped with IDL expressions) and that IDL-PMCFG parsing is $\mathrm {NP}$ -hard. We then introduce COMPĀ, a programming language extending Ranta’s Grammatical Framework (GF) and built as a high-level front-end formalism to IDL-PMCFG for practical grammar development. We present a parsing algorithm for IDL-PMCFG inspired by earlier Earley-style PMCFG parsing algorithms and Nederhof and Satta’s IDL graphs and give a worst-case estimate of its complexity as a function of several metrics on IDL expressions, the size of the input and a new notion of the _G_-density of a language. (shrink)

Theoretical explication of a growing body of empirical data on consciousness-related anomalous phenomena is unlikely to be achieved in terms of known physical processes. Rather, it will first be necessary to formulate the basic role of consciousness in the definition of reality before such anomalous experience can adequately be represented. This paper takes the position that reality is constituted only in the interaction of consciousness with its environment, and therefore that any scheme of conceptual organization developed to represent that reality (...) must reflect the processes of consciousness as well as those of its environment. In this spirit, the concepts and formalisms of elementary quantum mechanics, as originally proposed to explain anomalous atomic-scale physical phenomena, are appropriated via metaphor to represent the general characteristics of consciousness interacting with any environment. More specifically, if consciousness is represented by a quantum mechanical wave function, and its environment by an appropriate potential profile, Schrödinger wave mechanics defines eigenfunctions and eigenvalues that can be associated with the cognitive and emotional experiences of that consciousness in that environment. To articulate this metaphor it is necessary to associate certain aspects of the formalism, such as the coordinate system, the quantum numbers, and even the metric itself, with various impressionistic descriptors of consciousness, such as its intensity, perspective, approach/avoidance attitude, balance between cognitive and emotional activity, and receptive/assertive disposition. With these established, a number of the generic features of quantum mechanics, such as the wave/particle duality, and the uncertainty, indistinguishability, and exclusion principles, display metaphoric relevance to familiar individual and collective experiences. Similarly, such traditional quantum theoretic exercises as the central force field and atomic structure, covalent molecular bonds, barrier penetration, and quantum statistical collective behavior become useful analogies for representation of a variety of consciousness experiences, both normal and anomalous, and for the design of experiments to study these systematically. (shrink)

Let us look first at poetry. It is well known that by the fifteenth century, lyric poetry had undergone a radical transformation; the early lyric fluidity and formal variability had hardened into the nonlyric and even, some maintain, antilyric forms fixes which characterize the poetic formalism of late medieval France. Dispensing with the details of how and why this occurred, the essential point is that by the end of the Middle Ages, the poet in France and Burgundy saw himself (...) as an artisan of words, not as a singer.6 He refers to himself as a craftsman , and it is plain, sometimes painfully so, to anyone who reads the works that the rhétoriqueur is, indeed, an artisan of forms—or, if you will, an architecte de la parole, a specialist in verbal matter. He works words, sounds, metric and strophic forms into intricate patterns and arranges his elaborate designs in blocks of exact and harmonious symmetry. He is, in fact, from Machaut on, a virtuoso of the verbal equivalent of the architectural art of carrelage which adorned the princely château in which he worked and lived. No one familiar with the period will avoid noticing the strikingly similar types of patters in the poet’s works and in his surroundings.I have gathered elsewhere the visual documentation which bears out Zumthor’s suggestions quoted above with respect to the meticulously constructivist mentality of the Franco-Burgundian artisan. But the analogies I found are much more than perceptual. It is true that the elaborate designs on the walls, floors, ceilings, windows, woodwork, and so forth of the early Renaissance château are, indeed, composed of intricate blocks of material; but their function is not merely decorative , it is also narrative, with emblematic motifs and allegorical figures arrayed in linear patterns of “visual” discourse—the invariable “discours de la gloire” which silently proclaims the magnificence of the patron prince and proprietor of the château .7 6. A summary of internal and external factors in the transformation of lyric to Rhetoric is provided in my review of Die musikalische Erscheinungsform der Trouvèrepoesie by Hans-Herbert S. Räkel , in Romance Philology 34 : 250-58.7. This following collage of fragments from ML was constructed ôto serve as commentary on photographs of tile designs compared with verbal texts, in an earlier version of this paper , from which the examples in figs. 1-4 are taken.Culte de l’objet subtilement travaillé, au-delà de toute fonctionnalité primaire *** primat du labeur ardu, patient, du difficile, de l’inattendu *** les mots mêmes semblent travaillés d’un besoin de scientificité fictive, d’anoblissement par le savoir *** les … mots ne sont plus que les particules d’une parole dont la seule signification est globale *** matériau émancipé des contraintes de la phrase, transposé sur un plan où le signe devient le nom vide de ce signe *** goût du bricolage plutôt que de l’industrie; … du bariolage plus que du fondu et de la nuance; de l’équilibre numéral des parties plus que de la synthèse; du multiple plus que de l’un. Outil forgé martelé d’ “aornures” sans fonction utilitaire; enchâssements cubiques, coniques, pyramidaux, cruciformes du bâtiment … meubles marquetés, forrés de tiroirs minuscules et secrets [and so forth].For the iconography of these examples , see Emile Amé, Less Carrelages émaillés du Moyen Age et de la Renaissance , pp. 61-108. Jonathan Beck is associate professor of French at the University of Arizona. He is the author of Théâtre et propaganda aux débuts de la Réforme , a sequel to his edition and study, Le Concil de Basle: Le Origines du theater réformiste et partisan en France. (shrink)

Searching for information is critical in many situations. In medicine, for instance, careful choice of a diagnostic test can help narrow down the range of plausible diseases that the patient might have. In a probabilistic framework, test selection is often modeled by assuming that people's goal is to reduce uncertainty about possible states of the world. In cognitive science, psychology, and medical decision making, Shannon entropy is the most prominent and most widely used model to formalize probabilistic uncertainty and the (...) reduction thereof. However, a variety of alternative entropy metrics (Hartley, Quadratic, Tsallis, Rényi, and more) are popular in the social and the natural sciences, computer science, and philosophy of science. Particular entropy measures have been predominant in particular research areas, and it is often an open issue whether these divergences emerge from different theoretical and practical goals or are merely due to historical accident. Cutting across disciplinary boundaries, we show that several entropy and entropy reduction measures arise as special cases in a unified formalism, the Sharma–Mittal framework. Using mathematical results, computer simulations, and analyses of published behavioral data, we discuss four key questions: How do various entropy models relate to each other? What insights can be obtained by considering diverse entropy models within a unified framework? What is the psychological plausibility of different entropy models? What new questions and insights for research on human information acquisition follow? Our work provides several new pathways for theoretical and empirical research, reconciling apparently conflicting approaches and empirical findings within a comprehensive and unified information‐theoretic formalism. (shrink)

Equal Justice explores the role of the idea of equality in liberal theories of justice. The title indicates the book’s two-part thesis: first, I claim that justice is the central moral category in the socio-political domain; second, I argue for a specific conceptual and normative connection between the ideas of justice and equality. This pertains to the age-old question concerning the normative significance of equality in a theory of justice. The book develops an independent, systematic, and comprehensive theory of equality (...) and egalitarianism. The principal question is about the importance of equality in a theory of justice. More precisely, we should pose questions in four contracting circles: 1. Is justice the supreme value guiding our setup of the basic structure of society, or are there other, equally important values, such as recognition, care, communal belonging? 2. If justice is the highest guiding principle, which competing ideals—especially equality and freedom—ought to have precedence in a policy oriented toward justice? What status does the ideal of equality have in that framework? 3. If equality is a basic ideal of just policy, how should it be practically realized? What sort of equality (equal opportunity, equality of welfare, resource equality) should be demanded? 4. What patterned distribution of which specific goods does the ideal of equality demand? Which principles of distribution can be justified according to our justice ideal? To conclude and summarize: 5. What is the essential core of an egalitarian theory of justice, as opposed to an inegalitarian theory? These five questions structure the work’s order of argumentation. Part A elaborates the conceptual foundations and basic moral principles of justice and equality. Chapter I sets out to install justice as the central moral category in the socio-political domain. At the beginning of the first chapter, the conceptual foundations of justice are clarified. While not eliminating the classical distinctions between different forms of justice, I argue that the distributive paradigm is of primary importance. The primacy of justice in the socio-political domain is developed out of a confrontation with alternative positions, those which maintain either that justice generally, or distributive justice in particular, are subsidiary virtues. At the end of Chapter I, the first of the questions mentioned above is answered in a way that establishes justice as the guiding normative concept for the foundation and evaluation of any social order. To clarify the role of equality in a theory of justice, Chapter II separates the idea of equality into four different principles. They are organized in a way that begins with the most general and uncontroversial principle of equality, and progresses towards increasingly detailed and contested principles. There are two theses that articulate and defend the significance of equality for justice: First there is a conceptual connection between justice and equality, in that principles of formal and proportional equality are necessary in order to explicate the concept of justice. These two principles establish an unbreakable bond between justice and equality. Justice can only be explained—or so I argue—by reference to these and other (normative) principles of equality. The second thesis posits a normative relationship between justice and equality, which is disclosed by three substantive principles of equality: moral equality, the presumption of equality, and the principle of responsibility. I argue that the normative core of an egalitarian theory of justice is expressed by the latter two principles, which are themselves based on the first principle, that of moral equality. When we view one another as persons, what form of equality or equal treatment is normatively demanded? I argue that the answer to this question is given by the procedural principle of the presumption of equality: regardless of their apparent differences, all persons deserve strictly equal treatment, unless certain kinds of differences have whatever particular relevance would justify, on generally acceptable grounds, unequal treatment or unequal distribution. The justification of the presumption of equality is central to this work and has considerable importance. If the presumption principle’s validity can be justified by enlisting the principle of general justification, then the primacy of equality, and the essential argument for an egalitarian theory of justice, is established. This would likewise provide a procedure for the construction of a material theory of justice. The second question is answered thereby at the end of Chapter II: Equality should have primacy over competing ideals within a justice-oriented policy. The presumption of equality establishes this primacy and, at the same time, offers an appropriate metric and guideline for the construction of a material theory of distributive justice. The presumption of equality in Part B offers an elegant procedure for the development of a theory of distributive justice. Chapter III clearly sets out the necessary prerequisites that a theory of distribution must satisfy in order to determine a liberal-egalitarian distributional framework. We need to specify in which situation the distribution takes place; which goods are and are not to be distributed; in which respect the presumptive equality is to be produced; and by and to whom, and for what period, the relevant goods are to be distributed. The distribution is based on resources understood as general-purpose means. It is necessary to divide goods into different categories, since the justification for unequal treatment in one domain will not carry over into another. This makes presumptive equality necessarily complex. To that end, four spheres of justice are distinguished: (1) the political sphere, which involves allocating rights through the distribution of civil liberties; (2) the democratic sphere, in which political power and the rights of political participation are regulated; (3) the economic sphere, in which income and property are distributed; (4) the social sphere, in which social positions and opportunities are distributed. This framework of distributive justice answers the third of our guiding questions, about the nature of equality, in terms of equality of resources. Chapters IV and V set out the egalitarian distributive criteria for each sphere. I argue that the generally accepted, fundamental rights of classical liberalism are more effectively reconstructed by reference to the equal resource distribution presumptively required in those spheres. Chapter IV shows that when it comes to the first two spheres, those involving basic rights and freedoms and entitlement political participation, there can be no justified exceptions to the equal distribution of the relevant goods. That section argues, contrary to what we commonly find in theories of freedom or popular sovereignty, that the value of freedom and self-determination as the political basis of autonomy is best realized through the presumption of equal distribution. Chapter V deals with the other two spheres, those of economic goods and social positions, and argues for justified exceptions to equal distribution. In the economic sphere we find one principal reason favouring unequal distribution of resources, and three restrictions and compensations limiting that inequality. The basic exception to equal economic distribution arises from the unequal consequences of personal responsibility. From a suitably egalitarian standpoint, the principle of responsibility is the normative principle that determines which reasons justify economic inequality. Here the basic idea is that unequal shares of social goods are fair if they result from the choices and deliberate actions of the relevant parties. That individuals have to bear the costs of their own choices is a condition of autonomy. However, benefits or disadvantages arising from arbitrary and unmerited differences in social circumstances or natural endowments is unfair. The unequal consequences of independent decision-making and action must therefore be limited by compensating first for preferences, secondly for disadvantages, and thirdly by redistributing wealth in aid of the worse-off. I situations of emergency, compensating for disadvantages has priority over all other claims, owing to the urgency of the situation. Social inequalities go beyond the permissible limit if it is possible to improve the long-term social or economic situation of the worse-off by redistributing wealth to them. These exceptions lead to a complex system of free economic action within a framework of compensatory tax and transfer mechanisms. Finally, in the social sphere, the distribution of social positions, offices and opportunities must be structured to ensure that equally talented and motivated citizens have roughly equal chances of obtaining those offices or positions, irrespective of their economic or social class backgrounds. This compromise is permissible for reasons of freedom and prudence, and it makes a certain measure of inequality acceptable. The fourth of our guiding questions is answered accordingly. There are five principles of justice for the basic structure of society, and five legal principles that govern the special distribution of goods in the respective spheres—all are ranked according to their most defensible grounds of priority, ensuring that everyone is accorded equal justice. Chapter VI recapitulates the initial question of equality’s value. The conception of equal justice developed in this work postulates five principles of equality and five principles of law; these constitute an egalitarian framework because they support and promote social justice. Equality has value with respect to them, but is not given any independent, intrinsic value. That is why I call the account developed here a form of constitutive egalitarianism: justice is realized through the realization of equality, itself accomplished by applying the five postulates of equality and five distributive principles of law. This is an egalitarianism on two levels. The first level is involves the claim that morality or justice is conceptually connected with equality. The second level gives equality a substantial weight in what is conceptually validated at the first level, namely the presumption of equality, and constructs an appropriate interpretation and conception of distributive justice through principles of distribution for the individual spheres. The weight and importance of equality is shown by the distributive criteria applied to those spheres. This answers our final guiding question about the nature of an egalitarian theory. (shrink)

The concept of retro-avant-garde was first advanced by artists working in the late socialist and post-socialist contexts of Eastern Europe, Central Europe, and the territories of the ex-Yugoslavia. In general, its semantic field has been defined by a range of post-modern and mostly post-socialist art practices that draw formal, philosophical, and social inspiration from the politicized, powerfully utopian avant-gardes of the early decades of the twentieth-century, especially in the USSR and East-Central Europe. However, its paradoxical reference forward and backward (...) in time highlights the temporal dimensions of period concepts such as modernity, postmodernity, and avant-garde in ways that make retro-avant-garde worthy of theoretical reflection. I explore the nature of period concepts, which serve not only as historical metrics, but also as designations of basic characteristics of historicity, the configuration of the dimensions of past, present, and future in a given historical context and the limits and possibilities of historical experience and representation. I go on to explore the applicability to historiography of Gilles Deleuze's distinction, developed in his cinema theory, between "movement images" and "time images." In the case of historical thought, the distinction lies in whether the representation of time is thought to be a function of historical change or, on the contrary, whether the representation of historical change is qualified by the mode of time. I conclude by suggesting that if the avant-garde has primarily been conceptualized under the figure of "movement," retro-avant-garde reveals the degree to which classical avantgardism was dependent on an image of time: time itself as material to be artistically crafted and shaped into an historical experience appropriate to the modern age. (shrink)