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Added by: BjĆ¶rn Freter, Contributed by: Robin AttfieldAbstract: The Gaia theory of James Lovelock proposes that the Earth is a selfregulating system, or superorganism, maintaining conditions hospitable to contemporary planetary biota. Objections to this theory, concerning its alleged untestability and circularity, are considered and countered. Favourable evidence includes Lovelockās daisyworld model of a planet regulating its own temperatures and thus maintaining homeostasis, and his discoveries of actual regulatory mechanisms such as the biological generation of dimethyl sulphide, which removes sulphur from the oceans and seeds clouds whose albedo reduces solar radiation (a negative feedback mechanism). After some decades of scepticism, sections of the scientific community have partially endorsed Gaia theory, accepting that the Earth system behaves as if selfregulating. Whether or not this theory is acceptable in full, it has drawn attention to the need for preserving planetary biological cycles and for the planetary dimension to be incorporated in ethical decisionmaking, and thus for a planetary ethic.

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Added by: Simon Fokt, Contributed by: Simon Prosser
Abstract: Proponents of nonconceptual content have recruited it for various philosophical jobs. Some epistemologists have suggested that it may play the role of āthe givenā that Sellars is supposed to have exorcised from philosophy. Some philosophers of mind (e.g., Dretske) have suggested that it plays an important role in the project of naturalizing semantics as a kind of halfway between merely information bearing and possessing conceptual content. Here I will focus on a recent proposal by Jerry Fodor. In a recent paper he characterizes nonconceptual content in a particular way and argues that it is plausible that it plays an explanatory role in accounting for certain auditory and visual phenomena. So he thinks that there is reason to believe that there is nonconceptual content. On the other hand, Fodor thinks that nonconceptual content has a limited role. It occurs only in the very early stages of perceptual processing prior to conscious awareness. My paper is examines Fodorās characterization of nonconceptual content and his claims for its explanatory importance. I also discuss if Fodor has made a case for limiting nonconceptual content to nonconscious, subpersonal mental states.
Comment: Useful discussion of Fodor's view on nonconceptual content; I use the Fodor piece as main reading, and this as further reading.

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Added by: BjĆ¶rn Freter, Contributed by: Johanna ThomaAbstract: The chapter addresses the philosophical issues raised by the use of hypothetical modeling in the social sciences. Hypothetical modeling involves the construction and analysis of simple hypothetical systems to represent complex social phenomena for the purpose of understanding those social phenomena. To highlight its main features hypothetical modeling is compared both to laboratory experimentation and to computer simulation. In analogy with laboratory experiments, hypothetical models can be conceived of as scientific representations that attempt to isolate, theoretically, the working of causal mechanisms or capacities from disturbing factors. However, unlike experiments, hypothetical models need to deal with the epistemic uncertainty due to the inevitable presence of unrealistic assumptions introduced for purposes of analytical tractability. Computer simulations have been claimed to be able to overcome some of the strictures of analytical tractability. Still they differ from hypothetical models in how they derive conclusions and in the kind of understanding they provide. The inevitable presence of unrealistic assumptions makes the legitimacy of the use of hypothetical modeling to learn about the world a particularly pressing problem in the social sciences. A review of the contemporary philosophical debate shows that there is still little agreement on what social scientific models are and what they are for. This suggests that there might not be a single answer to the question of what is the epistemic value of hypothetical models in the social sciences.
Comment: This is a very useful and accessible overview of hypothetical modelling in the social sciences, and the philosophical debates it has given rise to.

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Added by: Nick NovelliAbstract:Ā The claim of the multiple realizability of mental states by brain states has been a major feature of the dominant philosophy of mind of the late 20th century. The claim is usually motivated by evidence that mental states are multiply realized, both within humans and between humans and other species. We challenge this contention by focusing on how neuroscientists differentiate brain areas. The fact that they rely centrally on psychological measures in mapping the brain and do so in a comparative fashion undercuts the likelihood that, at least within organic life forms, we are likely to find cases of multiply realized psychological functions.
Comment: One of the better arguments against multiple realizability. Could be used in any philosophy of mind course where that claim arises as a demonstration of how it could be challenged. A good deal of discussion about neuroscientific practices and methods, but not excessively technical.

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Added by: Laura JimenezSummary:Ā In this paper Beebee argues that the problem of induction, which she describes as a genuine sceptical problem, is the same for Humeans than for Necessitarians. Neither scientific essentialists nor Armstrong can solve the problem of induction by appealing to IBE (Inference to the Best Explanation), for both arguments take an illicit inductive step.
Comment: This paper describes in a comprehensible way Armstrong's and the Humean approaches to the problem of induction. Ideal for postgraduate philosophy of science courses, although it could be a further reading for undergraduate courses as well.

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Added by: Berta GrimauPublisher's Note: Professor Merrie Bergmann presents an accessible introduction to the subject of manyvalued and fuzzy logic designed for use on undergraduate and graduate courses in nonclassical logic. Bergmann discusses the philosophical issues that give rise to fuzzy logic  problems arising from vague language  and returns to those issues as logical systems are presented. For historical and pedagogical reasons, threevalued logical systems are presented as useful intermediate systems for studying the principles and theory behind fuzzy logic. The major fuzzy logical systems  Lukasiewicz, GĆ¶del, and product logics  are then presented as generalisations of threevalued systems that successfully address the problems of vagueness. A clear presentation of technical concepts, this book includes exercises throughout the text that pose straightforward problems, that ask students to continue proofs begun in the text, and that engage students in the comparison of logical systems.
Comment: In the words of the author: 'This textbook can be used as a complete basis for an introductory course on formal manyvalued and fuzzy logics, at either the upperlevel undergraduate or the graduate level, and it can also be used as a supplementary text in a variety of courses. There is considerable flexibility in either case. The truthvalued semantic chapters are independent of the algebraic and axiomatic ones, so that either of the latter may be skipped. Except for Section 13.3 of Chapter 13, the axiomatic chapters are also independent of the algebraic ones, and an instructor who chooses to skip the algebraic material can simply ignore the latter part of 13.3. Finally, Lukasiewicz fuzzy logic is presented independently of GĆ¶del and product fuzzy logics, thus allowing an instructor to focus solely on the former. There are exercises throughout the text. Some pose straightforward problems for the student to solve, but many exercises also ask students to continue proofs begun in the text, to prove results analogous to those in the text, and to compare the various logical systems that are presented.' The book does include a review of classical propositional and firstorder logic, but the students should've taken at least one basic logic course before getting into this material.

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Added by: Berta GrimauPublisher's note:Ā This volume is an accessible introduction to the subject of manyvalued and fuzzy logic suitable for use in relevant advanced undergraduate and graduate courses. The text opens with a discussion of the philosophical issues that give rise to fuzzy logic  problems arising from vague language  and returns to those issues as logical systems are presented. For historical and pedagogical reasons, three valued logical systems are presented as useful intermediate systems for studying the principles and theory behind fuzzy logic. The major fuzzy logical systems  Lukasiewicz, Godel, and product logics  are then presented as generalizations of threevalued systems that successfully address the problems of vagueness. Semantic and axiomatic systems for threevalued and fuzzy logics are examined along with an introduction to the algebras characteristic of those systems. A clear presentation of technical concepts, this book includes exercises throughout the text that pose straightforward problems, ask students to continue proofs begun in the text, and engage them in the comparison of logical systems.
Comment: This book is ideal for an intermediatelevel course on manyvalued and/or fuzzy logic. Although it includes a presentation of propositional and firstorder logic, it is intended for students who are familiar with classical logic. However, no previous knowledge of manyvalued or fuzzy logic is required. It can also be used as a secondary reading for a general course on nonclassical logics.

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Added by: Berta GrimauSummary:Ā This book is an introductory textbook on mathematical logic. It covers Propositional Logic and Predicate Logic. For each of these formalisms it presents its syntax and formal semantics as well as a tableauxstyle method of consistencychecking and a natural deductionstyle deductive calculus. Moreover, it discusses the metatheory of both logics.
Comment: This book would be ideal for an introductory course on symbolic logic. It presupposes no previous training in logic, and because it covers sentential logic through the metatheory of firstorder predicate logic, it is suitable for both introductory and intermediate courses in symbolic logic. The instructor who does not want to emphasize metatheory can simply omit Chapters 6 and 11. The chapters on truthtrees and the chapters on derivations are independent, so it is possible to cover truthtrees but not derivations and vice versa. However, the chapters on truthtrees do depend on the chapters presenting semantics; that is, Chapter 4 depends on Chapter 3 and Chapter 9 depends on Chapter 8. In contrast, the derivation chapters can be covered without first covering semantics. The Logic Book includes large exercise sets for all chapters. Answers to unstarred exercises appear in the Student Solutions Manual, available at www.mhhe.com/bergmann6e, while answers to starred exercises appear in the Instructor's Manual, which can be obtained by following the instructions on the same web page.

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Added by: Berta GrimauAbstract: This paper argues that the prominent accounts of logical knowledge have the consequence that they conflict with ordinary reasoning. On these accounts knowing a logical principle, for instance, is having a disposition to infer according to it. These accounts in particular conflict with socalled 'reasoned change in view', where someone does not infer according to a logical principle but revise their views instead. The paper also outlines a propositional account of logical knowledge which does not conflict with ordinary reasoning.
Comment: This paper proposes a certain characterisation of what it is to have knowledge of logical principles which makes it compatible with the way in which we reason ordinarily. It can be seen as an alternative to Harman's view in 'Change in View' according to which ordinary people do not at all 'employ' a deductive logic in reasoning. Thus this paper could be used in a course on the role of logic in reasoning, following the reading of Harman's work. More generally, this reading is suitable for any advanced undergraduate course or postgraduate course on the topic of rationality.

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Added by: Simon Fokt, Contributed by: Jurgis Karpus
Publisher's Note: In The Grammar of Society, first published in 2006, Cristina Bicchieri examines social norms, such as fairness, cooperation, and reciprocity, in an effort to understand their nature and dynamics, the expectations that they generate, and how they evolve and change. Drawing on several intellectual traditions and methods, including those of social psychology, experimental economics and evolutionary game theory, Bicchieri provides an integrated account of how social norms emerge, why and when we follow them, and the situations where we are most likely to focus on relevant norms. Examining the existence and survival of inefficient norms, she demonstrates how norms evolve in ways that depend upon the psychological dispositions of the individual and how such dispositions may impair social efficiency. By contrast, she also shows how certain psychological propensities may naturally lead individuals to evolve fairness norms that closely resemble those we follow in most modern societies.
Comment: Extracts from Bicchieri's book can be read in a course that covers game theory and social norms. Bicchieri's book is famous and highly praised for its contribution to our understanding of how social norms form and influence our choice behaviour in daytoday social interactions. Christina Bicchieri has recently also coauthored a revised version of the entry 'social norms' in the Stanford Encyclopedia of Philosophy (SEP).

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Added by: Berta GrimauPublisher's Note: Although sequent calculi constitute an important category of proof systems, they are not as well known as axiomatic and natural deduction systems. Addressing this deficiency, Proof Theory: Sequent Calculi and Related Formalisms presents a comprehensive treatment of sequent calculi, including a wide range of variations. It focuses on sequent calculi for various nonclassical logics, from intuitionistic logic to relevance logic, linear logic, and modal logic. In the first chapters, the author emphasizes classical logic and a variety of different sequent calculi for classical and intuitionistic logics. She then presents other nonclassical logics and metalogical results, including decidability results obtained specifically using sequent calculus formalizations of logics.
Comment: This book can be used in a variety of advanced undergraduate and postgraduate courses. Chapters 1, 2, 3 and 8 may be useful in an advanced undergraduate or beginning graduate course, where an emphasis is placed on classical logic and on a range of different proof calculi (mainly for classical logic). Chapters 4, 5 and 6 deal almost exclusively with nonclassical logics. Chapters 7 and 9 are rich in metalogical results, including results that have been obtained specifically using sequent calculus formalizations of various logics. These last five chapters might be used in a graduate course that embraces classical and nonclassical logics together with their metatheory. To facilitate the use of the book as a text in a course, the text is peppered with exercises. In general, the starring indicates an increase in difficulty, however, sometimes an exercise is starred simply because it goes beyond the scope of the book or it is very lengthy. Solutions to selected exercises may be found on the web at the URL www.ualberta.ca/Ėbimbo/ProofTheoryBook.

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Added by: Clotilde Torregrossa, Contributed by: Alex YatesAbstract: Gottlob Frege's work in logic and the foundations of mathemat ics centers on claims of logical entailment; most important among these is the claim that arithmetical truths are entailed by purely logical principles. Occupying a less central but nonetheless important role in Frege's work are claims about failures of entailment. Here, the clearest examples are his theses that the truths of geometry are not entailed by the truths of logic or of arithmetic, and that some of them are not entailed by each other. As he, and we, would put it: the truths of Eluclidean geometry are independent of the truths of logic, and some of them are independent of one another.' Frege's talk of independence and related notions sounds familiar to a modern ear: a proposition is independent of a collection of propositions just in case it is not a consequence of that collection, and a proposition or collection of propositions is consistent just in case no contradiction is a consequence of it. But some of Frege's views and procedures are decidedly tinmodern. Despite developing an extremely sophisticated apparattus for demonstrating that one claim is a consequience of others, Frege offers not a single demon stration that one claim is not a conseqtuence of others. Thus, in par tictular, he gives no proofs of independence or of consistency. This is no accident. Despite his firm commitment to the independence and consistency claims just mentioned, Frege holds that independence and consistency cannot systematically be demonstrated.2 Frege's view here is particularly striking in light of the fact that his contemporaries had a fruitful and systematic method for proving consistency and independence, a method which was well known to him. One of the clearest applications of this method in Frege's day came in David Hilbert's 1899 Foundations of Geometry,3 in which he es tablishes via essentially our own modern method the consistency and independence of various axioms and axiom systems for Euclidean geometry. Frege's reaction to Hilbert's work was that it was simply a failure: that its central methods were incapable of demonstrating consistency and independence, and that its usefulness in the founda tions of mathematics was highly questionable.4 Regarding the general usefulness of the method, it is clear that Frege was wrong; the last one hundred years of work in logic and mathemat ics gives ample evidence of the fruitfulness of those techniques which grow directly from the Hilbertstyle approach. The standard view today is that Frege was also wrong in his claim that Hilbert's methods fail to demonstrate consistency and independence. The view would seem to be that Frege largely missed Hilbert's point, and that a better under standing of Hilbert's techniques would have revealed to Frege their success. Despite Frege's historic role as the founder of the methods we now use to demonstrate positive consequenceresults, he simply failed, on this account, to understand the ways in which Hilbert's methods could be used to demonstrate negative consequenceresults. The purpose of this paper is to question this account of the Frege Hilbert disagreement. By 1899, Frege had a welldeveloped view of log ical consequence, consistency, and independence, a view which was central to his foundational work in arithmetic and to the epistemologi cal significance of that work. Given this understanding of the logical relations, I shall argue, Hilbert's demonstrations do fail. Successful as they were in demonstrating significant metatheoretic results, Hilbert's proofs do not establish the consistency and independence, in Frege's sense, of geometrical axioms. This point is important, I think, both for an understanding of the basis of Frege's epistemological claims about mathematics, and for an understanding of just how different Frege's conception of logic is from the modern modeltheoretic conception that has grown out of the Hilbertstyle approach to consistency.
Comment: Good for a historicallybased course on philosophy of logic or mathematics.

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Added by: Clotilde Torregrossa, Contributed by: Alex YatesPublisher's Note: In Frege's Conception of Logic Patricia A. Blanchette explores the relationship between Gottlob Frege's understanding of conceptual analysis and his understanding of logic. She argues that the fruitfulness of Frege's conception of logic, and the illuminating differences between that conception and those more modern views that have largely supplanted it, are best understood against the backdrop of a clear account of the role of conceptual analysis in logical investigation. The first part of the book locates the role of conceptual analysis in Frege's logicist project. Blanchette argues that despite a number of difficulties, Frege's use of analysis in the service of logicism is a powerful and coherent tool. As a result of coming to grips with his use of that tool, we can see that there is, despite appearances, no conflict between Frege's intention to demonstrate the grounds of ordinary arithmetic and the fact that the numerals of his derived sentences fail to corefer with ordinary numerals. In the second part of the book, Blanchette explores the resulting conception of logic itself, and some of the straightforward ways in which Frege's conception differs from its nowfamiliar descendants. In particular, Blanchette argues that consistency, as Frege understands it, differs significantly from the kind of consistency demonstrable via the construction of models. To appreciate this difference is to appreciate the extent to which Frege was right in his debate with Hilbert over consistency and independenceproofs in geometry. For similar reasons, modern results such as the completeness of formal systems and the categoricity of theories do not have for Frege the same importance they are commonly taken to have by his postTarskian descendants. These differences, together with the coherence of Frege's position, provide reason for caution with respect to the appeal to formal systems and their properties in the treatment of fundamental logical properties and relations.
Comment: This book would be a suitable resource for independent study, or for a historically oriented course on philosophy of logic, of math, or on early analytic philosophy, especially one which looks at philosophical approaches to axiomatic systems.

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Added by: Berta Grimau, Contributed by: Patricia BlanchetteAbstract: Description: This article is a short overview of philosophical and formal issues in the treatment and analysis of logical consequence. The purpose of the paper is to provide a brief introduction to the central issues surrounding two questions: (1) that of the nature of logical consequence and (2) that of the extension of logical consequence. It puts special emphasis in the role played by formal systems in the investigation of logical consequence.
Comment: This article can be used as background or overview reading in a course on the notion of logical consequence. It could also be used in a general course on philosophy of logic having a section on this topic. It makes very little use of technical notation, even though familiarity with firstorder logic is required. It closes with a useful list of suggested further readings.

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Added by: Berta Grimau, Contributed by: Patricia BlanchetteAbstract:Ā This paper examines the connection between modeltheoretic truth and necessary truth. It is argued that though the modeltheoretic truths of some standard languages are demonstrably "necessary" (in a precise sense), the widespread view of modeltheoretic truth as providing a general guarantee of necessity is mistaken. Several arguments to the contrary are criticized.
Comment: This text would be best used as secondary reading in an intermediate or an advanced philosophy of logic course. For example, it can be used as a secondary reading in a section on the connection between modeltheoretic truth and necessary truth.
Comment: This interdisciplinary survey of the Gaia hypothesis, its critics and its supporters, could be used in Philosophy of Science or Philosophy of Biology classes to clarify the concept of Gaia, which is often presented too vaguely by those who have not considered issues such as whether this hypothesis is falsifiable or not; it could also be used in Ethics classes because of its section on Gaian ethics. We show how Lovelock has devised indirect ways of testing this hypothesis (or better, the Gaia theory), how a critic (Kirchner) has presented it as either falsifiable but unsurprising or unfalsifiable and thus useless, and how a supporter, Tim Lenton has sought to explain how it can be reconciled with Darwinian evolution. Finally we show how elements of the theory have been endorsed by a scientific conference, but other aspects, such as the purposiveness of Gaia, were not endorsed.