This collection of articles on Models of Arithmetic is dedicated to the memory of Zygmunt Ratajczyk, who contributed a number of important results to the field, and who unexpectedly died in February 1994.

Solovay has shown that if F: [ω] ω → 2 is a clopen partition with recursive code, then there is an infinite homogeneous hyperarithmetic set for the partition (a basis result). Simpson has shown that for every 0 α , where α is a recursive ordinal, there is a clopen partition F: [ω] ω → 2 such that every infinite homogeneous set is Turing above 0 α (an anti-basis result). Here we refine these results, by associating the "order type" of (...) a clopen set with the Turing complexity of the infinite homogeneous sets. We also consider the Nash-Williams barrier theorem and its relation to the clopen Ramsey theorem. (shrink)

We give a new characterization of the hyperarithmetic sets: a set X of integers is recursive in e α if and only if there is a Turing machine which computes X and "halts" in less than or equal to the ordinal number ω α of steps. This result represents a generalization of the well-known "limit lemma" due to J. R. Shoenfield [Sho-1] and later independently by H. Putnam [Pu] and independently by E. M. Gold [Go]. As an application of this (...) result, we give a recursion theoretic analysis of clopen determinacy: there is a correlation given between the height α of a well-founded tree corresponding to a clopen game $A \subseteq \omega^\omega$ and the Turing degree of a winning strategy f for one of the players--roughly, f can be chosen to be recursive in 0 α and this is the best possible (see § 4 for precise results). (shrink)

Originating from work in operations research the cutting plane refutation systemCP is an extension of resolution, where unsatisfiable propositional logic formulas in conjunctive normal form are recognized by showing the non-existence of boolean solutions to associated families of linear inequalities. Polynomial sizeCP proofs are given for the undirecteds-t connectivity principle. The subsystemsCP q ofCP, forq≥2, are shown to be polynomially equivalent toCP, thus answering problem 19 from the list of open problems of [8]. We present a normal form theorem forCP (...) 2-proofs and thereby for arbitraryCP-proofs. As a corollary, we show that the coefficients and constant terms in arbitrary cutting plane proofs may be exponentially bounded by the number of steps in the proof, at the cost of an at most polynomial increase in the number of steps in the proof. The extensionCPLE +, introduced in [9] and there shown top-simulate Frege systems, is proved to be polynomially equivalent to Frege systems. Lastly, since linear inequalities are related to threshold gates, we introduce a new threshold logic and prove a completeness theorem. (shrink)

This reissue of his collection of early essays, Logico-Linguistic Papers, is published with a brand new introduction by Professor Strawson but, apart from minor ...

We define theories of bounded arithmetic, whose definable functions and relations are exactly those in certain complexity classes. Based on a recursion-theoretic characterization of NC in Clote , the first-order theory TNC, whose principal axiom scheme is a form of short induction on notation for nondeterministic polynomial-time computable relations, has the property that those functions having nondeterministic polynomial-time graph Θ such that TNC x y Θ are exactly the functions in NC, computable on a parallel random-access machine in polylogarithmic (...) parallel time with a polynomial number of processors.0 We then define three theories of weak second-order arithmetic which respectively characterize relations in the classes of alternating logarithmic time, logspace and nondeterministic logspace. (shrink)

A complete system of classical Aristotelian logic intended for honors high school and college.

Ohne Rücksicht auf disziplinäre Schranken bringt dieses Buch verschiedene nicht-reduktionistische Lerntheorien miteinander ins Gespräch. In einem offenen Diskurs, der die Konzepte zueinander in Beziehung setzt, werden die unterschiedlichen Perspektiven kritisch abgewogen und hinsichtlich ihrer Stärken und Schwächen diskutiert.

Delo se loteva vprašanja aktualnosti pojma subjekta v filozofiji in politiki skozi analizo tistih avtorjev, ki so ga domnevno najbolj radikalno pokopali: pokaže, da vznik radikalno novega in problematika subjekta zavzema osrednje mesto v Deleuzovi filozofiji, kakor tudi v Lyotardovi pozni misli posvečeni praznini, v Foucaultovi obravnavi biopolitike in biooblasti, v delu Negrija in Hardta o Imperiju, ter nazadnje v Badioujevi predelavi temeljnih filozofskih kategorij biti, resnice in subjekta, na osnovi katerih je dandanes znova možna renesansa filozofije. Ta ima po (...) Badiouju štiri razsežnosti, ki se v delu Vznik subjekta nenehno prepletajo: »V osnovi želja filozofije implicira razsežnost upora: ni filozofije brez nezadovoljstva mišljenja v njegovem soočenju s svetom, kakršen je. Pa vendar želja filozofije vključuje tudi logiko: to je, prepričanje v moč argumenta in uma.«. (shrink)

Pursuing the proof-theoretic program of Friedman and Simpson, we begin the study of the metamathematics of countable linear orderings by proving two main results. Over the weak base system consisting of arithmetic comprehension, II 1 1 -CA0 is equivalent to Hausdorff's theorem concerning the canonical decomposition of countable linear orderings into a sum over a dense or singleton set of scattered linear orderings. Over the same base system, ATR0 is equivalent to a version of the Continuum Hypothesis for linear orderings, (...) which states that every countable linear ordering either has countably many or continuum many Dedekind cuts. (shrink)

IΣ n andBΣ n are well known fragments of first-order arithmetic with induction and collection forΣ n formulas respectively;IΣ n 0 andBΣ n 0 are their second-order counterparts. RCA0 is the well known fragment of second-order arithmetic with recursive comprehension;WKL 0 isRCA 0 plus weak König's lemma. We first strengthen Harrington's conservation result by showing thatWKL 0 +BΣ n 0 is Π 1 1 -conservative overRCA 0 +BΣ n 0 . Then we develop some model theory inWKL 0 and illustrate (...) the use of formalized model theory by giving a relatively simple proof of the fact thatIΣ 1 provesBΣ n+1 to be Π n+2-conservative overIΣ n . Finally, we present a proof-theoretic proof of the stronger fact that theΠ n+2 conservation result is provable already inIΔ 0 + superexp. ThusIΣ n+1 proves 1-Con (BΣ n+1) andIΔ 0 +superexp proves Con (IΣ n )↔Con(BΣ n+1). (shrink)

The relationship of part to whole is one of the most fundamental there is; this is the first and only full-length study of this concept. This book shows that mereology, the formal theory of part and whole, is essential to ontology. Peter Simons surveys and criticizes previous theories, especially the standard extensional view, and proposes a more adequate account which encompasses both temporal and modal considerations in detail. 'Parts could easily be the standard book on mereology for the next (...) twenty or thirty years.' Timothy Williamson, Grazer Philosophische Studien. (shrink)

In this short but meaty book, Peter Unger questions the objective answers that have been given to central problems in philosophy. As Unger hypothesizes, many of these problems are unanswerable, including the problems of knowledge and scepticism, the problems of free will, and problems of causation and explanation. In each case, he argues, we arrive at one answer only relative to an assumption about the meaning of key terms, terms like "know" and like "cause," even while we arrive at (...) an opposite answer relative to quite different assumptions, but equally arbitrary assumptions, about what the key terms mean. (shrink)

Narrative thinking -- Narrative thinking about one's past -- Grief : a case study -- Narrative thinking about one's future -- Self-forgiveness : a case study -- The narrative sense of self -- Narrative, truth, life, and fiction.

While Hermann Levin Goldschmidt didn’t read Yiddish anarchists, there seems to have been a convergent evolution in their thinking. Goldschmidt’s looking up to Jewish lore as a source of liberating creativity is commonly encountered in Yiddish anarchist texts. His view of action as a constant response to internal and external challenges in the struggle for an open future is developed by Isaac Nachman Steinberg on the basis of nineteenth-century vitalism. Goldschmidt’s theory of anarchist individualism as willed self-limiting solidarity has a (...) compelling parallel in Hillel Solotaroff’s view of history. His use of impressionism and photography to eternalize the immediacy of human actuality is akin to Rudolf Rocker’s championing of decadent literature. In both cases, the goal of anarchism is not a dictatorship of the former downtrodden, but a continuous and contradictory evolution of freedom in ever-changing contexts. (shrink)

The norm of assertion, to be in force, is a social norm. What is the content of our social norm of assertion? Various linguistic arguments purport to show that to assert is to represent oneself as knowing. But to represent oneself as knowing does not entail that assertion is governed by a knowledge norm. At best these linguistic arguments provide indirect support for a knowledge norm. Furthermore, there are alternative, non-normative explanations for the linguistic data (as in recent work from (...) Van Elswyk). Direct arguments would rely on normative judgments about the permissibility or impermissibility of assertions with and without the speaker knowing the content asserted. John Turri's work experimental results purport to show that our norm of assertion is factive, and probably knowledge. But as a number of recent experimentalists (Kneer, Reuter and Broessel, Marsili and Wiegmann) have shown, Turri's results rely on the problemmatic use of 'should' as in 'Maria should assert that she owns a 1990 watch.' Correcting for this, these experimentalists provide strong evidence that our norm of assertion is not factive. The standard reply to evidence like this from the assertion of unlucky falsehoods is the excuse maneuver. But Marsili and Wiegmann, following Turri's protocol for testing for excuse validation, show that participants who judge that assertions unlucky falsehoods are permissible are not guilty of excuse validation. Given our current understanding of the experimental evidence, knowledge is not our norm of assertion. (shrink)

Metz holds that we can use African communal ethics to constitute global economic practices such as appropriation, production, distribution and consumption in such a way that promotes harmonious relations. In this article, I will show that Metz’s reformist approach to constituting the global economic practices is problematic as it fails to deal with the fundamental problem that pertains to a racialised world order that is structurally configured by coloniality of being. I will show that reformist approaches such as Metz’s use (...) of African communal ethics to constitute global economic practices in a way that promotes harmonious relations are undesirable attempts that are opposed and curtailed by a structural racialised logic/ontology of the world that governs and supervises the evolution of the world economic structures and practices in a way which undermines harmonious relations and in a way which causes economic marginalisation and impoverishment of historically disadvantaged indigenous Africans. (shrink)

Philosophy of music has flourished in the last thirty years, with great advances made in the understanding of the nature of music and its aesthetics. Peter Kivy has been at the center of this flourishing, and now offers his personal introduction to philosophy of music, a clear and lively explanation of how he sees the most important and interesting philosophical issues relating to music. Anyone interested in music will find this a stimulating introduction to some fascinating questions and ideas.

Abstractabstract:Karl Marx’s acerbic observation in the opening lines of The Eighteenth Brumaire that “all facts and personages of great importance in world history occur the first time as tragedy, the second as farce” may be profitably applied to a reconsideration of literary farce sui generis, a genre represented in this article by a long-neglected work of utopian fiction, Archibald Marshall’s Upsidonia (1915). Although Upsidonia’s current disregard is arguably undeserved, the article’s chief interest is not to reclaim the novel on aesthetic (...) grounds but to illuminate the mechanics of what Marx would call its “serious buffoonery.” In its persistent reversal of capitalist principles and relations, Upsidonia naturally invites readers to revisit Marx, whose mordant gambit may serve as a key to Marshall’s own farcical plot and praxis, rooted in return and repetition, the essential maneuvers of farce itself. (shrink)

This introduction by leading scholar Peter Trawny is the first to tackle the Black Notebooks, whose recent publication revealed the extent of Heidegger's anti-Semitism. Trawny directly confronts the most problematic aspects of Heidegger's thought, also fully surveying his work, from early writings to his magnum opus, Being and Time.

The so-called "Theology of Aristotle" is a translation of the Enneads of Plotinus, the most important representative of late ancient Platonism. It was produced in the 9th century CE within the circle of al-Kindī, one of the most important groups for the early reception of Greek thought in Arabic. In part because the "Theology" was erroneously transmitted under Aristotle's authorship, it became the single most important conduit by which Neoplatonism reached the Islamic world. It is referred to by such thinkers (...) as al-Fārābī, in an attempt to demonstrate the agreement between Platonism and Aristotelianism, Avicenna, who wrote a set of comments on the text, and later on thinkers of Safavid Persia including Mullā Ṣadrā. Yet the "Theology" is not just a translation. It may in fact more accurately be described as a creative paraphrase, which takes frequent liberties with the source text and even includes whole paragraphs' worth of new material. Adamson's book offers a philosophical interpretation of the changes introduced in the Arabic version. It is argued that these changes were in part intended to show the relevance of Plotinus' thought for contemporary Islamic culture, for instance by connecting the Neoplatonist theory of the First Principle to theological disputes within Islam over the status of God's attributes. At the same time the paraphrase reflects a tendency to harmonize the various strands of Greek thought, so that a critique by Plotinus of Aristotle's theory of the soul is subtly changed into a defense of Aristotle's theory against a possible misinterpretation. The upshot, or so Adamson argues, is that the "Theology" needs to be read as an original philosophical work in its own right, and understood within the context of the ʿAbbāsid era. (shrink)

This introduction to mathematical logic starts with propositional calculus and first-order logic. Topics covered include syntax, semantics, soundness, completeness, independence, normal forms, vertical paths through negation normal formulas, compactness, Smullyan's Unifying Principle, natural deduction, cut-elimination, semantic tableaux, Skolemization, Herbrand's Theorem, unification, duality, interpolation, and definability. The last three chapters of the book provide an introduction to type theory (higher-order logic). It is shown how various mathematical concepts can be formalized in this very expressive formal language. This expressive notation facilitates proofs (...) of the classical incompleteness and undecidability theorems which are very elegant and easy to understand. The discussion of semantics makes clear the important distinction between standard and nonstandard models which is so important in understanding puzzling phenomena such as the incompleteness theorems and Skolem's Paradox about countable models of set theory. Some of the numerous exercises require giving formal proofs. A computer program called ETPS which is available from the web facilitates doing and checking such exercises. Audience: This volume will be of interest to mathematicians, computer scientists, and philosophers in universities, as well as to computer scientists in industry who wish to use higher-order logic for hardware and software specification and verification. (shrink)

Morality and economic rationality: integrative economic ethics as the rational ethics of economic activity; Part II. Reflections on the Foundations of Economic ...

Peter Anstey presents a thorough and innovative study of John Locke's views on the method and content of natural philosophy. Focusing on Locke's Essay concerning Human Understanding, but also drawing extensively from his other writings and manuscript remains, Anstey argues that Locke was an advocate of the Experimental Philosophy: the new approach to natural philosophy championed by Robert Boyle and the early Royal Society who were opposed to speculative philosophy. On the question of method, Anstey shows how Locke's pessimism (...) about the prospects for a demonstrative science of nature led him, in the Essay, to promote Francis Bacon's method of natural history, and to downplay the value of hypotheses and analogical reasoning in science. But, according to Anstey, Locke never abandoned the ideal of a demonstrative natural philosophy, for he believed that if we could discover the primary qualities of the tiny corpuscles that constitute material bodies, we could then establish a kind of corpuscular metric that would allow us a genuine science of nature. It was only after the publication of the Essay, however, that Locke came to realize that Newton's Principia provided a model for the role of demonstrative reasoning in science based on principles established upon observation, and this led him to make significant revisions to his views in the 1690s. On the content of Locke's natural philosophy, it is argued that even though Locke adhered to the Experimental Philosophy, he was not averse to speculation about the corpuscular nature of matter. Anstey takes us into new terrain and new interpretations of Locke's thought in his explorations of his mercurialist transmutational chymistry, his theory of generation by seminal principles, and his conventionalism about species. (shrink)

A historical investigation of the exclusion of Africa and Asia from modern histories of philosophy.

Paulo Freire : the educator, his oeuvre, and changing contexts -- Holistic interpretations of Freire's work : a critical review -- Critical literacy, praxis, and emancipatory politics -- "Remaining on the same side of the river" : neo-liberalism, party movements, and the struggle for greater coherence -- Reinventing Freire in a Southern context : the Mediterranean -- Engaging with practice : a Freirean reflection on different pedagogical sites.

"Divination and Human Nature" casts a new perspective on the rich tradition of ancient divination--the reading of divine signs in oracles, omens, and dreams. Popular attitudes during classical antiquity saw these readings as signs from the gods while modern scholars have treated such beliefs as primitive superstitions. In this book, Peter Struck reveals instead that such phenomena provoked an entirely different accounting from the ancient philosophers. These philosophers produced subtle studies into what was an odd but observable fact--that humans (...) could sometimes have uncanny insights--and their work signifies an early chapter in the cognitive history of intuition. Examining the writings of Plato, Aristotle, the Stoics, and the Neoplatonists, Struck demonstrates that they all observed how, setting aside the charlatans and swindlers, some people had premonitions defying the typical bounds of rationality. Given the wide differences among these ancient thinkers, Struck notes that they converged on seeing this surplus insight as an artifact of human nature, projections produced under specific conditions by our physiology. For the philosophers, such unexplained insights invited a speculative search for an alternative and more naturalistic system of cognition. Recovering a lost piece of an ancient tradition, "Divination and Human Nature" illustrates how philosophers of the classical era interpreted the phenomena of divination as a practice closer to intuition and instinct than magic. (shrink)

What is ethics? Where do moral standards come from? Are they based on emotions, reason, or some innate sense of right and wrong? For many scientists, the key lies entirely in biology---especially in Darwinian theories of evolution and self-preservation. But if evolution is a struggle for survival, why are we still capable of altruism? In his classic study The Expanding Circle, Peter Singer argues that altruism began as a genetically based drive to protect one's kin and community members but (...) has developed into a consciously chosen ethic with an expanding circle of moral concern. Drawing on philosophy and evolutionary psychology, he demonstrates that human ethics cannot be explained by biology alone. Rather, it is our capacity for reasoning that makes moral progress possible. In a new afterword, Singer takes stock of his argument in light or recent research on the evolution of morality.--Publisher's description. (shrink)

The relationship of part to whole is one of the most fundamental there is, yet until now there has been no full-length study of this concept. This book shows that mereology, the formal theory of part and whole, is essential to ontology. Peter Simons surveys and criticizes previous theories, especially the standard extensional view, and proposes a more adequate account which encompasses both temporal and modal considerations in detail. This has far-reaching consequences for our understanding of such classical philosophical (...) concepts as identity, individual, class, substance and accident, matter, form, essence, dependence, and integral whole. It also enables the author to offer new solutions to long-standing problems surrounding these concepts, such as the Ship of Theseus Problem and the issue of mereological essentialism. The author shows by his use of formal techniques that classical philosophical problems are amenable to rigorous treatment, and the book represents a synthesis of issues and methods from the analytical tradition and from the older continental realist tradition of Brentano and the early Husserl. (shrink)

Children from various countries have been acknowledged and studied for their ability to philosophize, while, unfortunately, Filipino children have not received similar recognition. In this paper, I make a rather unpopular claim that Filipino children can and already are doing philosophy in their efforts to make sense of their existential conditions. “Doing philosophy” here refers to the act of being perplexed by one's own or other people's experiences and making an effort to comprehend them. Filipino children, are a vast and (...) diverse group, coming from various backgrounds, speaking different or even multiple languages, and representing rich cultures and unique circumstances. This diversity adds richness to the wide array of experiences from which existential questions can emerge. However, to truly comprehend the philosophical thinking of Filipino children, they need opportunities and guidance to explore their existential questions and solutions, regardless of how tentative or rudimentary these may seem to adults. Without such opportunities, it remains unclear to what extent their thinking engages with philosophical themes and issues. This not only offers Filipino adults a view of children’s inner worlds but also brings fresh perspectives to commonly held assumptions. (shrink)

Von Peter Sloterdijk kann man zu Recht sagen, daß jeder seiner Aufsätze, jeder seiner Vorträge auch ein ungeschriebenes Buch ist.

Timothy Williamson has argued that in the debate on modal ontology, the familiar distinction between actualism and possibilism should be replaced by a distinction between positions he calls contingentism and necessitism. He has also argued in favor of necessitism, using results on quantified modal logic with plurally interpreted second-order quantifiers showing that necessitists can draw distinctions contingentists cannot draw. Some of these results are similar to well-known results on the relative expressivity of quantified modal logics with so-called inner and outer (...) quantifiers. The present paper deals with these issues in the context of quantified modal logics with generalized quantifiers. Its main aim is to establish two results for such a logic: Firstly, contingentists can draw the distinctions necessitists can draw if and only if the logic with inner quantifiers is at least as expressive as the logic with outer quantifiers, and necessitists can draw the distinctions contingentists can draw if and only if the logic with outer quantifiers is at least as expressive as the logic with inner quantifiers. Secondly, the former two items are the case if and only if all of the generalized quantifiers are first-order definable, and the latter two items are the case if and only if first-order logic with these generalized quantifiers relativizes. (shrink)