We present a logical calculus for reasoning about information flow in quantum programs. In particular we introduce a dynamic logic that is capable of dealing with quantum measurements, unitary evolutions and entanglements in compound quantum systems. We give a syntax and a relational semantics in which we abstract away from phases and probabilities. We present a sound proof system for this logic, and we show how to characterize by logical means various forms of entanglement (e.g. the Bell states) and various (...) linear operators. As an example we sketch an analysis of the teleportation protocol. (shrink)

Many important criticisms to the possibility of global justice are advanced following one or another operationalization of the Rawlsian concept of a basic structure. The purpose of this paper is twofold: i) to show that the existence of a global basic structure is irrelevant from the standpoint of justice; ii) to set the stage for a cosmopolitan theory of global justice that employs satisficing sufficientarianism as a distributive principle. One of the main contentions is that the institutional-interactional cut in the (...) recent literature should be transcended. That is, the site of justice should be extended to incorporate both the efficiency of discharging one’s duties through a just institutional scheme and the moral value of promoting a good state of affairs through one’s own efforts. In order to avoid the overdemandingness objection, however, the selected principles of justice ought to belong to the sufficientarian family. Towards the end of the paper I sketch one such theory, satisficing sufficientarianism. (shrink)

In this paper, we investigate the social herding phenomenon known as informational cascades, in which sequential inter-agent communication might lead to epistemic failures at group level, despite availability of information that should be sufficient to track the truth. We model an example of a cascade, and check the correctness of the individual reasoning of each agent involved, using two alternative logical settings: an existing probabilistic dynamic epistemic logic, and our own novel logic for counting evidence. Based on this analysis, we (...) conclude that cascades are not only likely to occur but are sometimes unavoidable by "rational" means: in some situations, the group’s inability to track the truth is the direct consequence of each agent’s rational attempt at individual truth-tracking. Moreover, our analysis shows that this is even so when rationality includes unbounded higher-order reasoning powers, as well as when it includes simpler, non-Bayesian forms of heuristic reasoning. (shrink)

Stalnaker, 169–199 2006) introduced a combined epistemic-doxastic logic that can formally express a strong concept of belief, a concept of belief as ‘subjective certainty’. In this paper, we provide a topological semantics for belief, in particular, for Stalnaker’s notion of belief defined as ‘epistemic possibility of knowledge’, in terms of the closure of the interior operator on extremally disconnected spaces. This semantics extends the standard topological interpretation of knowledge with a new topological semantics for belief. We prove that the belief (...) logic KD45 is sound and complete with respect to the class of extremally disconnected spaces and we compare our approach to a different topological setting in which belief is interpreted in terms of the derived set operator. We also study belief revision as well as belief dynamics by providing a topological semantics for conditional belief and belief update modalities, respectively. Our setting based on extremally disconnected spaces, however, encounters problems when extended with dynamic updates. We then propose a solution consisting in interpreting belief in a similar way based on hereditarily extremally disconnected spaces, and axiomatize the belief logic of hereditarily extremally disconnected spaces. Finally, we provide a complete axiomatization of the logic of conditional belief and knowledge, as well as a complete axiomatization of the corresponding dynamic logic. (shrink)

We address the old question whether a logical understanding of Quantum Mechanics requires abandoning some of the principles of classical logic. Against Putnam and others (Among whom we may count or not E. W. Beth, depending on how we interpret some of his statements), our answer is a clear "no". Philosophically, our argument is based on combining a formal semantic approach, in the spirit of E. W. Beth's proposal of applying Tarski's semantical methods to the analysis of physical theories, with (...) an empirical-experimental approach to Logic, as advocated by both Beth and Putnam, but understood by us in the view of the operationalrealistic tradition of Jauch and Piron, i. e. as an investigation of "the logic of yes-no experiments" (or "questions"). Technically, we use the recently-developed setting of Quantum Dynamic Logic (Baltag and Smets 2005, 2008) to make explicit the operational meaning of quantum-mechanical concepts in our formal semantics. Based on our recent results (Baltag and Smets 2005), we show that the correct interpretation of quantum-logical connectives is dynamical, rather than purely propositional. We conclude that there is no contradiction between classical logic and (our dynamic reinterpretation of) quantum logic. Moreover, we argue that the Dynamic-Logical perspective leads to a better and deeper understanding of the "non-classicality" of quantum behavior than any perspective based on static Propositional Logic. (shrink)

This paper presents a simple decidable logic of functional dependence LFD, based on an extension of classical propositional logic with dependence atoms plus dependence quantifiers treated as modalities, within the setting of generalized assignment semantics for first order logic. The expressive strength, complete proof calculus and meta-properties of LFD are explored. Various language extensions are presented as well, up to undecidable modal-style logics for independence and dynamic logics of changing dependence models. Finally, more concrete settings for dependence are discussed: continuous (...) dependence in topological models, linear dependence in vector spaces, and temporal dependence in dynamical systems and games. (shrink)

We investigate the discrete (finite) case of the Popper–Renyi theory of conditional probability, introducing discrete conditional probabilistic models for knowledge and conditional belief, and comparing them with the more standard plausibility models. We also consider a related notion, that of safe belief, which is a weak (non-negatively introspective) type of “knowledge”. We develop a probabilistic version of this concept (“degree of safety”) and we analyze its role in games. We completely axiomatize the logic of conditional belief, knowledge and safe belief (...) over conditional probabilistic models. We develop a theory of probabilistic dynamic belief revision, introducing probabilistic “action models” and proposing a notion of probabilistic update product, that comes together with appropriate reduction laws. (shrink)

In the present chapter I try to determine to what extent the public policies adopted by Romanian governments following the fall of the communist regime contributed to alleviating the most egregious past injustice, the Holocaust. The measures taken for memorializing the Holocaust will be analysed through the lens of a mixed reparatory justice – relational egalitarian account. Employing such a framework entails a focus on symbolic reparations, meant to promote civic trust, social solidarity, and encourage the restoration of social and (...) cultural capital in societies affected by historical injustices. Such symbolic reparations can include public atonement, changing street names, establishing memorials, funding museums, including Holocaust study in the national curriculum, setting national days for the commemoration of the Holocaust, etc. The need for symbolic reparation has become increasingly clearer in the literature on Holocaust memorialization, and the present paper intends to go a step further, by providing researchers with a theoretical approach that can be used to make better sense of the effects of measures taken as part of the process of Holocaust remembrance. In the chapter I also address the issue of determining who the duty-bearers should be. I argue that there could be several indicators for reparatory justice, including in this case compensation programs and the establishment of institutions that would allow dialogue between descendants of the victims and descendants of the perpetrators, a sine qua non condition for restoring social trust in communities marked by violations of human rights, especially of such a scale as the Holocaust. (shrink)

We construct logical languages which allow one to represent a variety of possible types of changes affecting the information states of agents in a multi-agent setting. We formalize these changes by defining a notion of epistemic program. The languages are two-sorted sets that contain not only sentences but also actions or programs. This is as in dynamic logic, and indeed our languages are not significantly more complicated than dynamic logics. But the semantics is more complicated. In general, the semantics of (...) an epistemic program is what we call aprogram model. This is a Kripke model of ‘actions’,representing the agents' uncertainty about the current action in a similar way that Kripke models of ‘states’ are commonly used in epistemic logic to represent the agents' uncertainty about the current state of the system. Program models induce changes affecting agents' information, which we represent as changes of the state model, called epistemic updates. Formally, an update consists of two operations: the first is called the update map, and it takes every state model to another state model, called the updated model; the second gives, for each input state model, a transition relation between the states of that model and the states of the updated model. Each variety of epistemic actions, such as public announcements or completely private announcements to groups, gives what we call an action signature, and then each family of action signatures gives a logical language. The construction of these languages is the main topic of this paper. We also mention the systems that capture the valid sentences of our logics. But we defer to a separate paper the completeness proof. (shrink)

We take a logical approach to threshold models, used to study the diffusion of opinions, new technologies, infections, or behaviors in social networks. Threshold models consist of a network graph of agents connected by a social relationship and a threshold value which regulates the diffusion process. Agents adopt a new behavior/product/opinion when the proportion of their neighbors who have already adopted it meets the threshold. Under this diffusion policy, threshold models develop dynamically towards a guaranteed fixed point. We construct a (...) minimal dynamic propositional logic to describe the threshold dynamics and show that the logic is sound and complete. We then extend this framework with an epistemic dimension and investigate how information about more distant neighbors’ behavior allows agents to anticipate changes in behavior of their closer neighbors. Overall, our logical formalism captures the interplay between the epistemic and social dimensions in social networks. (shrink)

We introduce Arbitrary Public Announcement Logic with Memory (APALM), obtained by adding to the models a ‘memory’ of the initial states, representing the information before any communication took place (“the prior”), and adding to the syntax operators that can access this memory. We show that APALM is recursively axiomatizable (in contrast to the original Arbitrary Public Announcement Logic, for which the corresponding question is still open). We present a complete recursive axiomatization, that includes a natural finitary rule, and study this (...) logic’s expressivity and the appropriate notion of bisimulation. We then examine Group Announcement Logic with Memory (GALM), the extension of APALM obtained by adding to its syntax group announcement operators, and provide a complete finitary axiomatization (again in contrast to the original Group Announcement Logic, for which the only known axiomatization is infinitary). We also show that, in the memory-enhanced context, there is a natural reduction of the so-called coalition announcement modality to group announcements (in contrast to the memory-free case, where this natural translation was shown to be invalid). (shrink)

We propose a refinement of STIT logic to make it suitable to model causal agency and responsibility in basic multi-agent scenarios in which agents can interfere with one another. We do this by supplementing STIT semantics, first, with action types and, second, with a relation of opposing between action types. We exploit these novel elements to represent a test for potential causation, based on an intuitive notion of expected result of an action, and two tests for actual causation from the (...) legal literature, i.e. the but-for and the NESS tests. We then introduce three new STIT operators modeling corresponding notions of causal responsibility, which we call potential, strong, and plain responsibility, and use them to provide a fine-grained analysis of a number of case studies involving both individual agents and groups. (shrink)

We propose a new model for forming and revising beliefs about unknown probabilities. To go beyond what is known with certainty and represent the agent’s beliefs about probability, we consider a plausibility map, associating to each possible distribution a plausibility ranking. Beliefs are defined as in Belief Revision Theory, in terms of truth in the most plausible worlds. We consider two forms of conditioning or belief update, corresponding to the acquisition of two types of information: learning observable evidence obtained by (...) repeated sampling from the unknown distribution; and learning higher-order information about the distribution. The first changes only the plausibility map, but leaves the given set of possible distributions essentially unchanged; the second rules out some distributions, thus shrinking the set of possibilities, without changing their plausibility ordering.. We look at stability of beliefs under either of these types of learning, defining two related notions, as well as a measure of the verisimilitude of a given plausibility model. We prove a number of convergence results, showing how our agent’s beliefs track the true probability after repeated sampling, and how she eventually gains in a sense knowledge of that true probability. Finally, we sketch the contours of a dynamic doxastic logic for statistical learning. (shrink)

We investigate the process of truth-seeking by iterated belief revision with higher-level doxastic information . We elaborate further on the main results in Baltag and Smets (Proceedings of TARK, 2009a , Proceedings of WOLLIC’09 LNAI 5514, 2009b ), applying them to the issue of convergence to truth . We study the conditions under which the belief revision induced by a series of truthful iterated upgrades eventually stabilizes on true beliefs. We give two different conditions ensuring that beliefs converge to (...) “full” (complete) truth , as well as a condition ensuring only that they converge to true (but not necessarily complete) beliefs. (shrink)

In this paper we aim to examine a novel view on distributive justice, i.e. limitarianism, which claims that it is morally impermissible to be rich. Our main goal is to assess the two arguments provided by Ingrid Robeyns in favour of limitarianism, namely the democratic argument and the argument from unmet urgent needs and the two distinct limitarian views which these arguments give rise to. We claim that strong limitarianism, which is supported by the democratic argument, should be rejected as (...) it fails to fully instantiate the value of political equality, while having some other unattractive implications as well. By contrast, we argue that weak limitarianism, which is supported by the argument from unmet urgent needs, should be endorsed, albeit in a qualified version which also takes responsibility constraints into consideration. (shrink)

Numerous groups race to discover the gene biomarker whose alteration alone is indicative of a particular disease in all humans. Biomarkers are selected from the most frequently altered genes in large population cohorts. However, thousands of other genes are simultaneously affected, and, in each person, the same disease results from a unique, never-repeatable combination of gene alterations. Therefore, our Genomic Fabric Paradigm (GFP) switches the focus from the alteration of one particular gene to the overall change in selected groups of (...) functionally related genes. Biomarkers are of little therapeutic value, their high alterability indicating low protection by the homeostatic mechanisms as for minor players. Instead of these most alterable genes in all patients, GFP identifies in each patient the genes whose highly protected expression governs major functional pathways by controlling the expression of numerous other genes. Smart manipulation of such (commander) genes would have the maximum therapeutic benefit not for everybody but for the treated person. The genomic fabric is defined as the transcriptome associated with the most interconnected and stably expressed network of genes responsible for a particular functional pathway. The fabric exhibits specificity with respect to race/strain, sex, age, tissue/cell type, and lifestyle and environmental factors. It remodels during development, progression of a disease, and in response to external stimuli. GFP is powered by mathematically advanced analytical tools whose application is illustrated by reprocessing data from previously published gene expression experiments. (shrink)

The potential to achieve dynamic, scalable and cost-effective marketplaces and eCommerce solutions has driven recent research efforts towards so-called Semantic Web Services that are enriching Web services with machine-processable semantics. To this end, the Web Service Modeling Ontology (WSMO) provides the conceptual underpinning and a formal language for semantically describing all relevant aspects of Web services in order to facilitate the automatization of discovering, combining and invoking electronic services over the Web. In this paper we describe the overall structure of (...) WSMO by its four main elements: ontologies, which provide the terminology used by other WSMO elements, Web services, which provide access to services that, in turn, provide some value in some domain, goals that represent user desires, and mediators, which deal with interoperability problems between different WSMO elements. Along with introducing the main elements of WSMO, we provide a logical language for defining formal statements in WSMO together with some motivating examples from practical use cases which shall demonstrate the benefits of Semantic Web Services. (shrink)

We present a complete, decidable logic for reasoning about a notion of completely trustworthy evidence and its relations to justifiable belief and knowledge, as well as to their explicit justifications. This logic makes use of a number of evidence-related notions such as availability, admissibility, and “goodness” of a piece of evidence, and is based on an innovative modification of the Fitting semantics for Artemovʼs Justification Logic designed to preempt Gettier-type counterexamples. We combine this with ideas from belief revision and awareness (...) logics to provide an account for explicitly justified knowledge based on conclusive evidence that addresses the problem of omniscience. (shrink)

This is the first book on the provocative and innovative contributions to philosophy of language, metaphysics, the philosophy of mathematics, and logic made by Kit Fine, one of the world's foremost philosophers. Topics covered include meaning and representation, arbitrary objects, essence, ontological realism, and the metaphysics of modality.

This book illustrates the program of Logical-Informational Dynamics. Rational agents exploit the information available in the world in delicate ways, adopt a wide range of epistemic attitudes, and in that process, constantly change the world itself. Logical-Informational Dynamics is about logical systems putting such activities at center stage, focusing on the events by which we acquire information and change attitudes. Its contributions show many current logics of information and change at work, often in multi-agent settings where social behavior is essential, (...) and often stressing Johan van Benthem's pioneering work in establishing this program. However, this is not a Festschrift, but a rich tapestry for a field with a wealth of strands of its own. The reader will see the state of the art in such topics as information update, belief change, preference, learning over time, and strategic interaction in games. Moreover, no tight boundary has been enforced, and some chapters add more general mathematical or philosophical foundations or links to current trends in computer science. -/- -/- The theme of this book lies at the interface of many disciplines. Logic is the main methodology, but the various chapters cross easily between mathematics, computer science, philosophy, linguistics, cognitive and social sciences, while also ranging from pure theory to empirical work. Accordingly, the authors of this book represent a wide variety of original thinkers from different research communities. And their interconnected themes challenge at the same time how we think of logic, philosophy and computation. -/- -/- Thus, very much in line with van Benthem's work over many decades, the volume shows how all these disciplines forma natural unity in the perspective of dynamic logicians (broadly conceived) exploring their new themes today. And at the same time, in doing so, it offers a broader conception of logic with a certain grandeur, moving its horizons beyond the traditional study of consequence relations. (shrink)

The dissertation gives a second-order-logic-based explanation of modal incompleteness. The leading concept is that modal incompleteness is to be explained in terms of the incompleteness of standard second-order logic, since modal language is basically a second-order language. The development of Kripke-style semantics for modal logic has been underpinned by the conjecture that all modal systems are characterizable by classes of frames defined by first-order conditions on a binary relation. However, the discovery of certain incomplete modal systems has undermined the all-encompassing (...) feature of Kripke-style approach. There are logics not determined by any class of Kripke frames at all. ;In the dissertation I investigate a normal incomplete sentential modal system due to J. F. A. K. Van Benthem, and I address both the formal and the philosophical facets of modal incompleteness from the vantage point that modal logic is essentially second-order in its nature. Modal systems can be analyzed in terms of structures with a domain of second-order individuals that are assigned under an interpretation to propositional variables within languages of sentential modal logic. Hence, the phenomenon of there being incomplete modal systems can be accounted for through the incompleteness of standard second-order logic. ;Since second-order logic plays a crucial role in the explanation, Quine's animadversions upon second-order logic and in particular his views that second-order logic is 'Set Theory in Sheep's Clothing' are examined. Against Quine's stance I will seek to show that a vindication of second-order logic can be gotten provided a proper due is given to the sharp distinction between the logical notion of set which is the concern of second-order logic and the iterative notion of set which lies within the realm of set theory. (shrink)

Fischer’s approach for structure elucidation of linear aldohexoses is still the most widespread alternative in textbooks for carbohydrates. However, in post-Fischer era, a series of remarkable discoveries and inventions were made in different laboratories, and by their use a more comprehensive and coherent strategy for structure elucidation of linear isomeric aldohexoses can be elaborated. Fischer used the exceptional properties of d-mannose for the knowledge of configuration of C-2 and called it the key of the gate to stereochemistry. We bring the (...) evidence that Fischer had an alternative to this monosaccharide, d-idose. Fischer discovered the correct structure of the enantiomers of tartaric acid by pure intuition but Bijvoet proved it experimentally by means of X-rays. Hybridization, a concept taken by L. Pauling from biology, reconciled physics and chemistry concerning the valence of carbon atom and explained the stereochemical picture that had been empirically elaborated by Van’t Hoff and Le Bel. Other chemical transformations of monosaccharides, useful in the elucidation of their structure, have been also discovered or invented in post-Fischer era. (shrink)

This article argues that there are at least three different versions of methodological nationalism: state-centrism (unjustified supremacy granted to the nation-state), territorialism (understanding space as divided in territories), and groupism (equating society with the nation-state’s society). If these three versions are logically distinct, as it will be shown, the typology can serve as a tool to weight the influence of methodological nationalism in the social sciences. The paper has three sections arguing that 1) the three versions are all present in (...) the literature on methodological nationalism without always being distinguished; 2) the epistemological problems raised by methodological nationalism are sometimes misunderstood as ontological or normative questions about globalization and national borders; 3) the three versions of methodological nationalism can be shown to be logically independent by a few examples. (shrink)

Migrant women are often stereotyped. Some scholars associate the feminization of migration with domestic work and criticize the “care drain” as a new form of imperialism that the First World imposes on the Third World. However, migrant women employed as domestic workers in Northern America and Europe represent only 2% of migrant women worldwide and cannot be seen as characterizing the “feminization of migration”. Why are migrant domestic workers overestimated? This paper explores two possible sources of bias. The first is (...) sampling: conclusions about “care drain” are often generalized from small samples of domestic workers. The second stems from the affect heuristic: imagining children left behind by migrant mothers provokes strong feelings of injustice which trump other considerations. The paper argues that neither source of bias is unavoidable and finds evidence of gender stereotypes in the “care drain” construal. (shrink)

We formalise a notion of dynamic rationality in terms of a logic of conditional beliefs on plausibility models. Similarly to other epistemic statements, dynamic rationality changes its meaning after every act of learning, and it may become true after players learn it is false. Applying this to extensive games, we "simulate" the play of a game as a succession of dynamic updates of the original plausibility model: the epistemic situation when a given node is reached can be thought of as (...) the result of a joint act of learning that the node is reached. We then use the notion of "stable belief, i.e. belief that is preserved during the play of the game, in order to give an epistemic condition for backward induction: rationality and common knowledge of stable belief in rationality. This condition is weaker than Aumann's and compatible with the implicit assumptions underlying Stalnaker's criticism of Aumann's proof. The "dynamic" nature of our concept of rationality explains why our condition avoids the apparent circularity of the "backward induction paradox": it is consistent to believe in a player's rationality after updating with his irrationality. (shrink)

When it comes to specifying the moral duties we bear towards future generations, most political philosophers position themselves on what could be regarded as a safe ground. A variant of the Lockean proviso is commonplace in the literature on intergenerational justice, taking the form of an obligation to bestow upon future people a minimum of goods necessary for reaching a certain threshold of well-being (Meyer, 2017). Furthermore, even this minimum is often frowned upon, given the non-identity problem and the challenges (...) this presents to the topic of justice between generations. Additional issues are raised at the level of non-ideal theory, the most significant being the problem of non-compliance (Gosseries and Meyer, 2009).In this paper I intend to probe the limits of “practical political possibility” (Rawls 1999), by inquiring whether embracing the sufficiency view (Frankfurt, 1987; Crisp, 2003; Benbaji, 2005) as a distributive pattern and capabilities as a metric can lead to more burdensome obligations for present generations. More specifically, I try to show that we have a duty to invest in research that aims at prolonging the lifespan of humans (the idea can already be found in the sufficientarian literature, for instance in Farrelly, 2007). Moreover, given the Earth’s limited resources, we ought to encourage the terraforming of other planets in order to make them inhabitable for (future) people.I argue that these two seemingly far-fetched projects are in fact worthwhile goals to pursue on the one hand, and moral obligations on the other hand. Nonetheless, they are not the only ones we ought to take on; for instance, we must simultaneously pursue them and try to improve the prospects of those who fall under a sufficiency threshold here and now. That is, specifying these (prima facie) duties towards future generations is connected with stronger obligations towards the current generation.Towards the end of the paper I engage in a discussion regarding the role of the feasibility constraint in a theory of justice, as rationales pertaining to feasibility are perhaps going to be the most recurrent criticisms raised against my proposal. To that end, I defend limitarian policies, which aim at setting an upper limit to how much money individuals are allowed to possess (Robeyns, 2017; Volacu and Dumitru, 2019). (shrink)

We study the learning power of iterated belief revision methods. Successful learning is understood as convergence to correct, i.e., true, beliefs. We focus on the issue of universality: whether or not a particular belief revision method is able to learn everything that in principle is learnable. We provide a general framework for interpreting belief revision policies as learning methods. We focus on three popular cases: conditioning, lexicographic revision, and minimal revision. Our main result is that conditioning and lexicographic revision can (...) drive a universal learning mechanism, provided that the observations include only and all true data, and provided that a non-standard, i.e., non-well-founded prior plausibility relation is allowed. We show that a standard, i.e., well-founded belief revision setting is in general too narrow to guarantee universality of any learning method based on belief revision. We also show that minimal revision is not universal. Finally, we consider situations in which observational errors may occur. Given a fairness condition, which says that only finitely many errors occur, and that every error is eventually corrected, we show that lexicographic revision is still universal in this setting, while the other two methods are not. (shrink)

In this paper we show how ideas coming from two areas of research in logic can reinforce each other. The first such line of inquiry concerns the "dynamic turn" in logic and especially the formalisms inspired by Propositional Dynamic Logic (PDL); while the second line concerns research into the logical foundations of Quantum Physics, and in particular the area known as Operational Quantum Logic, as developed by Jauch and Piron (Helve Phys Acta 42: 842-848, 1969), Pirón (Foundations of Quantum Physics, (...) 1976). By bringing these areas together we explain the basic ingredients of Dynamic Quantum Logic, a new direction of research in the logical foundations of physics. (shrink)

In this paper we show how recent concepts from Dynamic Logic, and in particular from Dynamic Epistemic logic, can be used to model and interpret quantum behavior. Our main thesis is that all the non-classical properties of quantum systems are explainable in terms of the non-classical flow of quantum information. We give a logical analysis of quantum measurements (formalized using modal operators) as triggers for quantum information flow, and we compare them with other logical operators previously used to model various (...) forms of classical information flow: the “test” operator from Dynamic Logic, the “announcement” operator from Dynamic Epistemic Logic and the “revision” operator from Belief Revision theory. The main points stressed in our investigation are the following: (1) The perspective and the techniques of “logical dynamics” are useful for understanding quantum information flow. (2) Quantum mechanics does not require any modification of the classical laws of “static” propositional logic, but only a non-classical dynamics of information. (3) The main such non-classical feature is that, in a quantum world, all information-gathering actions have some ontic side-effects. (4) This ontic impact can affect in its turn the flow of information, leading to non-classical epistemic side-effects (e.g. a type of non-monotonicity) and to states of “objectively imperfect information”. (5) Moreover, the ontic impact is non-local: an information-gathering action on one part of a quantum system can have ontic side-effects on other, far-away parts of the system. (shrink)