Suicide attack is the most virulent and horrifying form of terrorism in the world today. The mere rumor of an impending suicide attack can throw thousands of people into panic. This occurred during a Shi‘a procession in Iraq in late August 2005, causing hundreds of deaths. Although suicide attacks account for a minority of all terrorist acts, they are responsible for a majority of all terrorism-related casualties, and the rate of attacks is rising rapidly across the globe. During 2000–2004, there (...) were 472 suicide attacks in 22 countries, killing more than 7,000 and wounding tens of thousands. Most have been carried out by Islamist groups claiming religious motivation, also known as jihadis. Rand Corp. vice president and terrorism analyst Bruce Hoffman has found that 80 percent of suicide attacks since 1968 occurred after the September 11 attacks, with jihadis representing 31 of the 35 responsible groups. More suicide attacks occurred in 2004 than in any previous year, and 2005 has proven even more deadly, with attacks in Iraq alone averaging more than one per day, according to data gathered by the U.S. military. The July 2005 London and Sinai bombings, a second round of bombings at tourist destinations in Bali in October, coordinated hotel bombings in Jordan in November, the arrival of suicide bombings in Bangladesh in December, a record year of attacks in Afghanistan, and daily bombings in Iraq have spurred renewed interest in suicide terrorism, with recent analyses stressing the strategic logic, organizational structure, and rational calculation involved. Whereas they once primarily consisted of organized campaigns by militarily weak forces aiming to end the perceived occupation of their homeland, as argued by University of Chicago political scientist Robert Pape in Dying to Win: The Strategic Logic of Suicide Terrorism, suicide attacks today serve as banner actions for a thoroughly modern, global diaspora inspired by religion and claiming the role of vanguard for a massive, media-driven transnational political awakening. Living mostly in the diaspora and undeterred by the threat of retaliation against original home populations, jihadis, who are frequently middle-class, secularly well educated, but often “born-again” radical Islamists, including converts from Christianity, embrace apocalyptic visions for humanity's violent salvation. In Muslim countries and across western Europe, bright and idealistic Muslim youth, even more than the marginalized and dispossessed, internalize the jihadi story, illustrated on satellite television and the Internet with the ubiquitous images of social injustice and political repression with which much of the Muslim world's bulging immigrant and youth populations intimately identifies. From the suburbs of Paris to the jungles of Indonesia, I have interviewed culturally uprooted and politically restless youth who echo a stunningly simplified and decontextualized message of martyrdom for the sake of global jihad as life's noblest cause. They are increasingly as willing and even eager to die as they are to kill. The policy implications of this change in the motivation, organization, and calculation of suicide terrorism may be as novel as hitherto neglected. Many analysts continue to claim that jihadism caters to the destitute and depraved, the craven and criminal, or those who “hate freedom.” Politicians and pundits have asserted that jihadism is nihilistic and immoral, with no real program or humanity. Yet, jihadism is none of these things. Do we really understand the causes of today's suicide terrorism? Do suicide attacks stem mainly from a political cause, such as military occupation? Do they need a strong organization, such as Al Qaeda? What else could be done to turn the rising tide of martyrdom? (shrink)
In a book that challenges the most widely held ideas of why individuals engage in collective conflict, Russell Hardin offers a timely, crucial explanation of group action in its most destructive forms. Contrary to those observers who attribute group violence to irrationality, primordial instinct, or complex psychology, Hardin uncovers a systematic exploitation of self-interest in the underpinnings of group identification and collective violence. Using examples from Mafia vendettas to ethnic violence in places such as Bosnia and Rwanda, (...) he describes the social and economic circumstances that set this violence into motion. Hardin explains why hatred alone does not necessarily start wars but how leaders cultivate it to mobilize their people. He also reveals the thinking behind the preemptive strikes that contribute to much of the violence between groups, identifies the dangers of "particularist" communitarianism, and argues for government structures to prevent any ethnic or other group from having too much sway. Exploring conflict between groups such as Serbs and Croats, Hutu and Tutsi, Northern Irish Catholics and Protestants, Hardin vividly illustrates the danger that arises when individual and group interests merge. In these examples, groups of people have been governed by movements that managed to reflect their members' personal interests--mainly by striving for political and economic advances at the expense of other groups and by closing themselves off from society at large. The author concludes that we make a better and safer world if we design our social institutions to facilitate individual efforts to achieve personal goals than if we concentrate on the ethnic political makeup of our respective societies. (shrink)
Kurt Gödel, mathematician and logician, was one of the most influential thinkers of the twentieth century. Gödel fled Nazi Germany, fearing for his Jewish wife and fed up with Nazi interference in the affairs of the mathematics institute at the University of Göttingen. In 1933 he settled at the Institute for Advanced Study in Princeton, where he joined the group of world-famous mathematicians who made up its original faculty. His 1940 book, better known by its short title, The Consistency (...) of the Continuum Hypothesis, is a classic of modern mathematics. The continuum hypothesis, introduced by mathematician George Cantor in 1877, states that there is no set of numbers between the integers and real numbers. It was later included as the first of mathematician David Hilbert's twenty-three unsolved math problems, famously delivered as a manifesto to the field of mathematics at the International Congress of Mathematicians in Paris in 1900. In The Consistency of the Continuum Hypothesis Gödel set forth his proof for this problem. In 1999, Time magazine ranked him higher than fellow scientists Edwin Hubble, Enrico Fermi, John Maynard Keynes, James Watson, Francis Crick, and Jonas Salk. He is most renowned for his proof in 1931 of the 'incompleteness theorem,' in which he demonstrated that there are problems that cannot be solved by any set of rules or procedures. His proof wrought fruitful havoc in mathematics, logic, and beyond. (shrink)
This proceedings volume contains most of the invited talks presented at the colloquium. The main topics treated are the model theory of arithmetic and algebra, the semantics of natural languages, and applications of mathematical logic to complexity theory. The volume contains both surveys by acknowledged experts and original research papers presenting advances in these disciplines.
Pure Inductive Logic is the study of rational probability treated as a branch of mathematical logic. This monograph, the first devoted to this approach, brings together the key results from the past seventy years, plus the main contributions of the authors and their collaborators over the last decade, to present a comprehensive account of the discipline within a single unified context.
We present a number of modal logics to reason about group norms. As a preliminary step, we discuss the ontological status of the group to which the norms are applied, by adapting the classification made by Christian List of collective attitudes into aggregated, common, and corporate attitudes. Accordingly, we shall introduce modality to capture aggregated, common, and corporate group norms. We investigate then the principles for reasoning about those types of modalities. Finally, we discuss the relationship between (...)group norms and types of collective responsibility. (shrink)
Judgment aggregation studies how individual opinions on a given set of propositions can be aggregated to form a consistent group judgment on the same propositions. Despite the simplicity of the problem, seemingly natural aggregation procedures fail to return consistent collective outcomes, leading to what is now known as the doctrinal paradox. The first occurrences of the paradox were discovered in the legal realm. However, the interest of judgment aggregation is much broader and extends to political philosophy, epistemology, social choice (...) theory, and computer science. The aim of this paper is to provide a concise survey of the discipline and to outline some of the most pressing questions and future lines of research. (shrink)
Public announcement logic is an extension of epistemic logic with dynamic operators that model the effects of all agents simultaneously and publicly acquiring the same piece of information. One of the extensions of PAL, group announcement logic, allows quantification over announcements made by agents. In GAL, it is possible to reason about what groups can achieve by making such announcements. It seems intuitive that this notion of coalitional ability should be closely related to the notion of (...) distributed knowledge, the implicit knowledge of a group. Thus, we study the extension of GAL with distributed knowledge, and in particular possible interaction properties between GAL operators and distributed knowledge. The perhaps surprising result is that, in fact, there are no interaction properties, contrary to intuition. We make this claim precise by providing a sound and complete axiomatisation of GAL with distributed knowledge. We also consider several natural variants of GAL with distributed knowledge, as well as some other related logic, and compare their expressive power. (shrink)
We investigate a series of logics that allow to reason about agents' actions, abilities, and their knowledge about actions and abilities. These logics include Pauly's Coalition Logic CL, Alternating-time Temporal Logic ATL, the logic of ‘seeing-to-it-that', and epistemic extensions thereof. While complete axiomatizations of CL and ATL exist, only the fragment of the STIT language without temporal operators and without groups has been axiomatized by Xu. We start by recalling a simplification of the Ldm that has been (...) proposed in previous work, together with an alternative semantics in terms of standard Kripke models. We extend that semantics to groups via a principle of superadditivity, and give a sound and complete axiomatization that we call Ldm G. We then add a temporal ‘next' operator to Ldm G, and again give a sound and complete axiomatization. We show that Ldm G subsumes coalition logic CL. Finally, we extend these logics with standard S5 knowledge operators. This enables us to express that agents see to something under uncertainty about the present state or uncertainty about which action is being taken. We focus on the epistemic extension of X-Ldm G, noted E-X-Ldm G. In accordance with established terminology in the planning community, we call this extension of X-Ldm G the conformant X-Ldm G. The conformant X-Ldm G enables us to express that agents are able to perform a uniform strategy. We conclude that in that respect, our epistemic extension of X-Ldm G is better suited than epistemic extensions of ATL. (shrink)
We introduce a deductive system Bal which models the logic of balance of opposing forces or of balance between conflicting evidence or influences. ‘‘Truth values’’ are interpreted as deviations from a state of equilibrium, so in this sense, the theorems of Bal are to be interpreted as balanced statements, for which reason there is only one distinguished truth value, namely the one that represents equilibrium. The main results are that the system Bal is algebraizable in the sense of [5] (...) and its equivalent algebraic semantics BAL is definitionally equivalent to the variety of abelian lattice ordered groups, that is, the categories of the algebras in BAL and of ℓ–groups are isomorphic (see [10], Ch.4, 4). We also prove the deduction theorem for Bal and we study different kinds of semantic consequence associated to Bal. Finally, we prove the co-NP-completeness of the tautology problem of Bal. (shrink)
We prove that a finitely generated group is context-free whenever its Cayley-graph has a decidable monadic second-order theory. Hence, by the seminal work of Muller and Schupp, our result gives a logical characterization of context-free groups and also proves a conjecture of Schupp. To derive this result, we investigate general graphs and show that a graph of bounded degree with a high degree of symmetry is context-free whenever its monadic second-order theory is decidable. Further, it is shown that the (...) word problem of a finitely generated group is decidable if and only if the first-order theory of its Cayley-graph is decidable. (shrink)
Rational Pavelka logic extends Lukasiewicz infinitely valued logic by adding truth constants r̄ for rationals in [0, 1]. We show that this is a conservative extension. We note that this shows that provability degree can be defined in Lukasiewicz logic. We also give a counterexample to a soundness theorem of Belluce and Chang published in 1963.
The Berlin Group for scientific philosophy was active between 1928 and 1933 and was closely related to the Vienna Circle. In 1930, the leaders of the two Groups, Hans Reichenbach and Rudolf Carnap, launched the journal Erkenntnis. However, between the Berlin Group and the Vienna Circle, there was not only close relatedness but also significant difference. Above all, while the Berlin Group explored philosophical problems of the actual practice of science, the Vienna Circle, closely following Wittgenstein, was (...) more interested in problems of the language of science. The book includes first discussion ever (in three chapters) on Walter Dubislav’s logic and philosophy. Two chapters are devoted to another author scarcely explored in English, Kurt Grelling, and another one to Paul Oppenheim who became an important figure in the philosophy of science in the USA in the 1940s–1960s. Finally, the book discusses the precursor of the Nord-German tradition of scientific philosophy, Jacob Friedrich Fries. Mehr anzeigen Weniger anzeigen . (shrink)
Russell Hardin writes from a particular perspective, that of rational choice theory. His broad—and ambitious—overall project is to “understand the sway of groups in our time” or, in an alternative formulation, “to understand the motivations of those who act on behalf of groups and to understand how they come to identify with the groups for which they act”.
B.K.Matilal, and earlier J.F.Staal, have suggested a reading of the `Nyaya five limb schema' (also sometimes referred to as the Indian Schema or Hindu Syllogism) from Gotama's Nyaya-Sutra in terms of a binary occurrence relation. In this paper we provide a rational justification of a version of this reading as Analogical Reasoning within the framework of Polyadic Pure Inductive Logic.
There are several ways to quantify over public announcements. The most notable are reflected in arbitrary, group, and coalition announcement logics, with the latter being the least studied so far. In the present work, we consider coalition announcements through the lens of group announcements, and provide a complete axiomatisation of a logic with coalition announcements. To achieve this, we employ a generalisation of group announcements. Moreover, we study some logical properties of both coalition and group (...) announcements that have not been studied before. (shrink)
We consider two formalizations of the notion of irrelevance as a rationality principle within the framework of (Carnapian) Inductive Logic: Johnson's Sufficientness Principle, JSP, which is classically important because it leads to Carnap's influential Continuum of Inductive Methods and the recently proposed Weak Irrelevance Principle, WIP. We give a complete characterization of the language invariant probability functions satisfying WIP which generalizes the Nix-Paris Continuum. We argue that the derivation of two very disparate families of inductive methods from alternative (...) perceptions of 'irrelevance' is an indication that this notion is imperfectly understood at present. (shrink)
Can one extend crisp Peano arithmetic PA by a possibly many-valued predicate Tr(x) saying "x is true" and satisfying the "dequotation schema" $\varphi \equiv \text{Tr}(\bar{\varphi})$ for all sentences φ? This problem is investigated in the frame of Lukasiewicz infinitely valued logic.
We consider the version of Pure Inductive Logic which obtains for the language with equality and a single unary function symbol giving a complete characterization of the probability functions on this language which satisfy Constant Exchangeability.
We consider the problem of induction over languages containing binary relations and outline a way of interpreting and constructing a class of probability functions on the sentences of such a language. Some principles of inductive reasoning satisfied by these probability functions are discussed, leading in turn to a representation theorem for a more general class of probability functions satisfying these principles.
It is well known that there is a categorical equivalence between lattice-ordered Abelian groups and conical BCK-algebras. The aim of this paper is to study this equivalence from the perspective of logic, in particular, to study the relationship between two deductive systems: conical logic Co and a logic of l-groups, Balo. In [GAL 04] the authors introduce a system Bal which models the logic of balance of opposing forces with a single distinguished truth value, that represents (...) equilibrium. Its equivalent algebraic semantics BAL is definitionally equivalent to the variety of l-groups. In this paper we define the system Balo which is equivalent to Bal and whose Lindenbaum-Tarski algebra is an l-group. On the other hand, we define the conic logic Co and we prove that it can be naturally merged in the system Balo. Also, we prove that every formula of Balo has a normal form that depends on translations of formulas of Co. (shrink)
A family of symmetries of polyadic inductive logic are described which in turn give rise to the purportedly rational Permutation Invariance Principle stating that a rational assignment of probabilities should respect these symmetries. An equivalent, and more practical, version of this principle is then derived.
In the context of continuous logic, this paper axiomatizes both the class \ of lattice-ordered groups isomorphic to C for X compact and the subclass \ of structures existentially closed in \; shows that the theory of \ is \-categorical and admits elimination of quantifiers; establishes a Nullstellensatz for \ and \; shows that \\in \mathcal {C}\) has a prime-model extension in \ just in case X is Boolean; and proves that in a sense relevant to continuous logic, (...) positive formulas admit in \ elimination of quantifiers to positive formulas. (shrink)
A necessary and sufficient condition in terms of a de Finetti style representation is given for a probability function in Polyadic Inductive Logic to satisfy being part of a Language Invariant family satisfying Spectrum Exchangeability. This theorem is then considered in relation to the unary Carnap and Nix–Paris Continua.
We extend the framework of Inductive Logic to Second Order languages and introduce Wilmers' Principle, a rational principle for probability functions on Second Order languages. We derive a representation theorem for functions satisfying this principle and investigate its relationship to the first order principles of Regularity and Super Regularity.
We propose an Analogy Principle in the context of Unary Inductive Logic and characterize the probability functions which satisfy it. In particular in the case of a language with just two predicates the probability functions satisfying this principle correspond to solutions of Skyrmsʼ ‘Wheel of Fortune’.
We investigate the relative probabilistic support afforded by the combination of two analogies based on possibly different, structural similarity (as opposed to e.g. shared predicates) within the context of Pure Inductive Logic and under the assumption of Language Invariance. We show that whilst repeated analogies grounded on the same structural similarity only strengthen the probabilistic support this need not be the case when combining analogies based on different structural similarities. That is, two analogies may provide less support than each (...) would individually. (shrink)
We give a unified account of some results in the development of Polyadic Inductive Logic in the last decade with particular reference to the Principle of Spectrum Exchangeability, its consequences for Instantial Relevance, Language Invariance and Johnson's Sufficientness Principle, and the corresponding de Finetti style representation theorems.
We give a brief account of some de Finetti style representation theorems for probability functions satisfying Spectrum Exchangeability in Polyadic Inductive Logic, together with applications to Non-splitting, Language Invariance, extensions with Equality and Instantial Relevance.
The present paper investigates the groups of automorphisms for some lattices of modal logics. The main results are the following. The lattice of normal extensions of S4.3, NExtS4.3, has exactly two automorphisms, NExtK.alt1 has continuously many automorphisms. Moreover, any automorphism of NExtS4 fixes all logics of finite codimension. We also obtain the following characterization of pretabular logics containing S4: a logic properly extends a pretabular logic of NExtS4 iff its lattice of extensions is finite and linear.
We develop several aspects of local and global stability in continuous first order logic. In particular, we study type-definable groups and genericity.
Can one extend crisp Peano arithmetic PA by a possibly many-valued predicate Tr saying "x is true" and satisfying the "dequotation schema" $\varphi \equiv \text{Tr}$ for all sentences $\varphi$? This problem is investigated in the frame of Lukasiewicz infinitely valued logic.
Experimental research by social and cognitive psychologists has established that cooperative groups solve a wide range of problems better than individuals. Cooperative problem solving groups of scientific researchers, auditors, financial analysts, air crash investigators, and forensic art experts are increasingly important in our complex and interdependent society. This comprehensive textbook--the first of its kind in decades--presents important theories and experimental research about group problem solving. The book focuses on tasks that have demonstrably correct solutions within mathematical, logical, scientific, or (...) verbal systems, including algebra problems, analogies, vocabulary, and logical reasoning problems.The book explores basic concepts in group problem solving, social combination models, group memory, group ability and world knowledge tasks, rule induction problems, letters-to-numbers problems, evidence for positive group-to-individual transfer, and social choice theory. The conclusion proposes ten generalizations that are supported by the theory and research on group problem solving. Group Problem Solving is an essential resource for decision-making research in social and cognitive psychology, but also extremely relevant to multidisciplinary and multicultural problem-solving teams in organizational behavior, business administration, management, and behavioral economics. (shrink)