Can thought arise out of matter? Can self, soul, consciousness, “I” arise out of mere matter? If it cannot, then how can you or I be here? I Am a Strange Loop argues that the key to understanding selves and consciousness is the “strange loop”—a special kind of abstract feedback loop inhabiting our brains. The most central and complex symbol in your brain is the one called “I.” The “I” is the nexus in our brain, one of many symbols seeming (...) to have free will and to have gained the paradoxical ability to push particles around, rather than the reverse. How can a mysterious abstraction be real—or is our “I” merely a convenient fiction? Does an “I” exert genuine power over the particles in our brain, or is it helplessly pushed around by the laws of physics? These are the mysteries tackled in I Am a Strange Loop, Douglas Hofstadter's first book-length journey into philosophy since Gödel, Escher, Bach. Compulsively readable and endlessly thought-provoking, this is a moving and profound inquiry into the nature of mind. (shrink)

In this article, I make the case for the continued relevance of Plato’s Timaeus. I begin by sketching Allan Bloom’s picture of the natural sciences today in The Closing of the American Mind, according to which the natural sciences are, objectionably, increasingly specialized and have ejected humans qua humans from their purview. I argue that Plato’s Timaeus, despite the falsity of virtually all of its scientific claims, provides a model for how we can pursue scientific questions in a comprehensive way (...) that stresses their connections to other disciplines, including the humanities, and that puts humanity qua humanity back in the picture. I then argue that being led by Plato’s philosophy to return humanity conceptually to the natural world can improve our thinking regarding climate change and other important environmental crises. (shrink)

Chapter INTRODUCTION Charles Sanders Peirce is quickly becoming the dominant figure in the history of American philosophy. The breadth and depth of his work ...

The American thinker Charles Sanders Peirce, best known as the founder of pragmatism, has been influential not only in the pragmatic tradition but more recently in the philosophy of science and the study of semiotics, or sign theory. Strands of System provides an accessible overview of Peirce's systematic philosophy for those who are beginning to explore his thinking and its import for more recent trends in philosophy.

The partial ordering of Medvedev reducibility restricted to the family of Π0 1 classes is shown to be dense. For two disjoint computably enumerable sets, the class of separating sets is an important example of a Π0 1 class, which we call a ``c.e. separating class''. We show that there are no non-trivial meets for c.e. separating classes, but that the density theorem holds in the sublattice generated by the c.e. separating classes.

Abstract.The partial ordering of Medvedev reducibility restricted to the family of Π01 classes is shown to be dense. For two disjoint computably enumerable sets, the class of separating sets is an important example of a Π01 class, which we call a ``c.e. separating class''. We show that there are no non-trivial meets for c.e. separating classes, but that the density theorem holds in the sublattice generated by the c.e. separating classes.

Cenzer, D., R. Downey, C. Jockusch and R.A. Shore, Countable thin Π01 classes, Annals of Pure and Applied Logic 59 79–139. A Π01 class P {0, 1}ω is thin if every Π01 subclass of P is the intersection of P with some clopen set. Countable thin Π01 classes are constructed having arbitrary recursive Cantor- Bendixson rank. A thin Π01 class P is constructed with a unique nonisolated point A and furthermore A is of degree 0’. It is shown that no (...) set of degree ≥0” can be a member of any thin Π01 class. An r.e. degree d is constructed such that no set of degree d can be a member of any thin Π01 class. It is also shown that between any two distinct comparable r.e. degrees, there is a degree that contains a set which is of rank one in some thin Π01 class. It is shown that no maximal set can have rank one in any Π01 class, while there exist maximal sets of rank 2. The connection between Π01 classes, propositional theories and recursive Boolean algebras is explored, producing several corollaries to the results on Π01 classes. For example, call a recursive Boolean algebra thin if it has no proper nonprincipal recursive ideals. Then no thin recursive Boolean algebra can have a maximal ideal of degree ≥0”. (shrink)

Berkeley, Hume, and Russell rejected the traditional analysis of substances in terms of qualities which are supported by an "unknowable substratum." To them the proper alternative seemed obvious. Eliminate the substratum in which qualities are alleged to inhere, leaving a bundle of coexisting qualities--a view that we may call the Bundle Theory or BT. But by rejecting only part of the traditional substratum theory instead of replacing it entirely, Bundle Theories perpetuate certain confusions which are found in the Substratum Doctrine. (...) I examine two major types of BT developed by Russell and by G. F. Stout with the intention of showing that (1) the seemingly innocuous concept of "a quality" employed by these versions cannot be used to state their theories coherently, and (2) the fatal problems that the BT encounters point to a more satisfactory and interesting alternative to both the Substratum Doctrine and the BT. This is a view that I call the Qualified Particulars Theory. In a final section I draw morals from this discussion that apply to the analogous Humean view that a mind is a "bundle of perceptions and sensations.". (shrink)

This paper is a continuation of the authors' work , where the main problem considered was whether a given recursive structure is recursively isomorphic to a polynomial-time structure. In that paper, a recursive Abelian group was constructed which is not recursively isomorphic to any polynomial-time Abelian group. We now show that if every element of a recursive Abelian group has finite order, then the group is recursively isomorphic to a polynomial-time group. Furthermore, if the orders are bounded, then the group (...) is recursively isomorphic to a polynomial-time group with universe A being the set of tally representations of natural numbers Tal = s{;1s};* or the set of binary representations of the natural numbers Bin. We also construct a recursive Abelian group with all elements of finite order but which has elements of arbitrary large finite order which is not isomorphic to any polynomial-time group with universe Tal or Bin. Similar results are obtained for structures , where f is a permutation on the set A. (shrink)

We argue that (1) a purported example of an infinite inference we humans can actually perform admits a faithful, finitary description, and (2) infinite inference contravenes any view which does not grant our minds uncomputable powers. These arguments block the strategy, dating back to Carnap's Logical Syntax of Language, of using infinitary inference rules to secure the determinacy of arithmetical truth on conventionalist grounds.

The central problem considered in this paper is whether a given recursive structure is recursively isomorphic to a polynomial-time structure. Positive results are obtained for all relational structures, for all Boolean algebras and for the natural numbers with addition, multiplication and the unary function 2x. Counterexamples are constructed for recursive structures with one unary function and for Abelian groups and also for relational structures when the universe of the structure is fixed. Results are also given which distinguish primitive recursive structures, (...) exponential-time structures and structures with honest witnesses. (shrink)

An important source of doubt about our knowledge of the "external world" is the thought that all of our sensory experience could be delusive without our realizing it. Such wholesale questioning of the deliverances of all forms of perception seems to leave no resources for successfully justifying our belief in the existence of an objective world beyond our subjective experiences. I argue that there is there is a fatal flaw in the very expression of philosophical doubt about the "external world." (...) Therefore, no such justification is necessary. The feature of skepticism which I believe renders it vulnerable is the assumption that each of us has a right to be certain of his own existence as a subject of conscious experience even in the face of comprehensive doubt about our empirical beliefs. (shrink)

In order to improve our understanding of the components that reflect functionally important processes during reward anticipation and consumption, we used principle components analyses (PCA) to separate and quantify averaged ERP data obtained from each stage of a modified monetary incentive delay (MID) task. Although a small number of recent ERP studies have reported that reward and loss cues potentiate ERPs during anticipation, action preparation, and consummatory stages of reward processing, these findings are inconsistent due to temporal and spatial overlap (...) between the relevant electrophysiological components. Our results show three components following cue presentation are sensitive to incentive cues (N1, P3a, P3b). In contrast to previous research, reward‐related enhancement occurred only in the P3b, with earlier components more sensitive to break‐even and loss cues. During feedback anticipation, we observed a lateralized centroparietal negativity that was sensitive to response hand but not cue type. We also show that use of PCA on ERPs reflecting reward consumption successfully separates the reward positivity from the independently modulated feedback‐P3. Last, we observe for the first time a new reward consumption component: a late negativity distributed over the left frontal pole. This component appears to be sensitive to response hand, especially in the context of monetary gain. These results illustrate that the time course and sensitivities of electrophysiological activity that follows incentive cues do not follow a simple heuristic in which reward incentive cues produce enhanced activity at all stages and substages. (shrink)

Several diagrams and tables from review articles during the Ox-Phos Controversy serve as an occasion to assess the nature of competition in models of theory choice in science. Many models follow "Super-Bowl" principles of polar, either-or, winner-take-all competition. A significant alternative highlighted by this episode, however, is the differentiation of domains. Incommensurability and the partial divergence of overlapping domains serve both as signals and context for shifting frameworks of competition. Appropriate strategies may thus help researchers diagnose the status of competition (...) and shape their research accordingly. (shrink)

A Π01 class is an effectively closed set of reals. We study properties of these classes determined by cardinality, measure and category as well as by the complexity of the members of a class P. Given an effective enumeration {Pe:e < ω} of the Π01 classes, the index set I for a certain property is the set of indices e such that Pe has the property. For example, the index set of binary Π01 classes of positive measure is Σ02 complete. (...) Various notions of boundedness are discussed and classified. For example, the index set of the recursively bounded classes is Σ03 complete and the index set of the recursively bounded classes which have infinitely many recursive members is Π04 complete. Consideration of the Cantor-Bendixson derivative leads to index sets in the transfinite levels of the hyperarithmetic hierarchy. (shrink)

In this engaging book, Douglas Anderson begins with the assumption that philosophy—the Greek love of wisdom—is alive and well in American culture. At the same time, professional philosophy remains relatively invisible. Anderson traverses American life to find places in the wider culture where professional philosophy in the distinctively American tradition can strike up a conversation. How might American philosophers talk to us about our religious experience, or political engagement, or literature—or even, popular music? Anderson’s second aim is to find (...) places where philosophy happens in nonprofessional guises—cultural places such as country music, rock’n roll, and Beat literature. He not only enlarges the tradition of American philosophers such as John Dewey and William James by examining lesser-known figures such as Henry Bugbee and Thomas Davidson, but finds the theme and ideas of American philosophy in some unexpected places, such as the music of Hank Williams, Tammy Wynette, and Bruce Springsteen, and the writingsof Jack Kerouac.The idea of “philosophy Americana” trades on the emergent genre of “music Americana,” rooted in traditional themes and styles yet engaging our present experiences. The music is “popular” but not thoroughly driven by economic considerations, and Anderson seeks out an analogous role for philosophical practice, where philosophy and popular culture are co-adventurers in the life of ideas. Philosophy Americana takes seriously Emerson’s quest for the extraordinary in the ordinary and James’s belief that popular philosophy can still be philosophy. (shrink)

We describe here an interdisciplinary lab science course for non-majors using the history of science as a curricular guide. Our experience with diverse instructors underscores the importance of the teachers and classroom dynamics, beyond the curriculum. Moreover, the institutional political context is central: are courses for non-majors valued and is support given to instructors to innovate? Two sample projects are profiled.

I highlight a category of experiment-what I am calling 'demonstrations'-that differs in justificatory mode and argumentative role from the more familiar 'crucial tests'. 'Tests' are constructed such that alternative results are equally and symmetrically informative; they help discriminate between alternative solutions within a problem-field, where questions are shared. 'Demonstrations' are notably asymmetrical (for example, "failures" are often not telling), yet they are effective, if not "crucial," in interparadigm dispute, to legitimate questions themselves. The Ox-Phos Controversy in bioenergetics serves as an (...) integral case study. (shrink)

This important book was the first serious work of philosophy to address the question: Do adults have a moral right to use drugs for recreational purposes? Many critics of the 'war on drugs' denounce law enforcement as counterproductive and ineffective. Douglas Husak argues that the 'war on drugs' violates the moral rights of adults who want to use drugs for pleasure, and that criminal laws against such use are incompatible with moral rights. This is not a polemical tract but (...) a scrupulously argued work of philosophy that takes full account of all available data concerning drug use in the United States today. The author is careful to describe the properties a recreational drug would have to possess before the state would be justified in prohibiting it. Since criminal laws against the use of recreational drugs are justified neither by the harm users cause to themselves nor by the harm users cause to each other, Professor Husak concludes that such laws are, in almost all cases, unjustified. (shrink)

This investigation joins recent research on problems with ambiguity in two fields, argumentation and computing. In argumentation, there is a concern with fallacies arising from ambiguity, including equivocation and amphiboly. In computing, the development of agent communication languages is based on conversation policies that make it possible to have information exchanges on the internet, as well as other forms of dialogue like persuasion and negotiation, in which ambiguity is a problem. Because it is not possible to sharply differentiate between problems (...) arising from ambiguity and those arising from vagueness, obscurity and indeterminacy, some study of the latter is included. The semantic web is based on what are called ontologies, or systems of classification of concepts, shown to be useful tools for dealing with these problems. (shrink)

This paper continues joint work of the authors with P. Clote, R. Soare and S. Wainer (Annals of Pure and Applied Logic, vol. 31 (1986), pp. 145--163). An element x of the Cantor space 2 ω is said have rank α in the closed set P if x is in $D^\alpha(P)\backslash D^{\alpha + 1}(P)$ , where D α is the iterated Cantor-Bendixson derivative. The rank of x is defined to be the least α such that x has rank α in (...) some Π 0 1 set. The main result of the five-author paper is that for any recursive ordinal λ + n (where λ is a limit and n is finite), there is a point with rank λ + n which is Turing equivalent to O (λ + 2n) . All ranked points constructed in that paper are Π 0 2 singletons. We now construct a ranked point which is not a Π 0 2 singleton. In the previous paper the points of high rank were also of high hyperarithmetic degree. We now construct ▵ 0 2 points with arbitrarily high rank. We also show that every nonrecursive RE point is Turing equivalent to an RE point of rank one and that every nonrecursive ▵ 0 2 point is Turing equivalent to a hyperimmune point of rank one. We relate Clote's notion of the height of a Π 0 1 singleton in the Baire space with the notion of rank. Finally, we show that every hyperimmune point x is Turing equivalent to a point which is not ranked. (shrink)

We develop a theory of LOGSPACE structures and apply it to construct a number of examples of Abelian Groups which have LOGSPACE presentations. We show that all computable torsion Abelian groups have LOGSPACE presentations and we show that the groups ${\mathbb {Z}, Z(p^{\infty})}$ , and the additive group of the rationals have LOGSPACE presentations over a standard universe such as the tally representation and the binary representation of the natural numbers. We also study the effective categoricity of such groups. For (...) example, we give conditions are given under which two isomorphic LOGSPACE structures will have a linear space isomorphism. (shrink)

Important examples of $\Pi^0_1$ classes of functions $f \in {}^\omega\omega$ are the classes of sets (elements of ω 2) which separate a given pair of disjoint r.e. sets: ${\mathsf S}_2(A_0, A_1) := \{f \in{}^\omega2 : (\forall i < 2)(\forall x \in A_i)f(x) \neq i\}$ . A wider class consists of the classes of functions f ∈ ω k which in a generalized sense separate a k-tuple of r.e. sets (not necessarily pairwise disjoint) for each k ∈ ω: ${\mathsf S}_k(A_0,\ldots,A_k-1) := (...) \{f \in {}^\omega k : (\forall i < k) (\forall x \in A_i) f(x) \neq i\}$ . We study the structure of the Medvedev degrees of such classes and show that the set of degrees realized depends strongly on both k and the extent to which the r.e. sets intersect. Let ${\mathcal S}^m_k$ denote the Medvedev degrees of those ${\mathsf S}_k(A_0,\ldots,A_{k-1})$ such that no m + 1 sets among A 0,...,A k-1 have a nonempty intersection. It is shown that each ${\mathcal S}^m_k$ is an upper semi-lattice but not a lattice. The degree of the set of k-ary diagonally nonrecursive functions $\mathsf{DNR}_k$ is the greatest element of ${\mathcal S}^1_k$ . If 2 ≤ l < k, then 0 M is the only degree in ${\mathcal S}^1_l$ which is below a member of ${\mathcal S}^1_k$ . Each ${\mathcal S}^m_k$ is densely ordered and has the splitting property and the same holds for the lattice ${\mathcal L}^m_k$ it generates. The elements of ${\mathcal S}^m_k$ are exactly the joins of elements of ${\mathcal S}^1_i$ for $\lceil{k \over m}\rceil \leq i \leq k$. (shrink)

The traditional analysis of substances in terms of qualities which are supported by a "substratum" was rejected by conscientious empiricists like Berkeley, Hume and Russell on the grounds that only qualities, not the substratum, could be experienced. To these philosophers the proper alternative seemed obvious. One simply eliminates the "unknowable" element in which qualities are alleged to inhere. In Russell's words, "What would commonly be called a 'thing' is nothing but a bundle of coexisting qualities such as redness, hardness, etc."' (...) But this empiricist formula has difficulties of its own, and some philosophers have attempted to develop other views of particulars which avoid the errors of the Substratum Doctrine on the one hand and the Bundle-of¬Qualities Theory on the other.2 Discussions of what this third alternative might be have generally approached the question through an examination of the epistemologically suspect concepts of a substratum and its close relative, the concept of a "bare particular". The concept of a quality of something, because it seemingly presents no epistemological difficulties, has attracted much less critical attention. This imbalance in critical interest is unfortunate, however, for a close scrutiny of this latter concept, especially in its role as the key element in the "bundle" analysis of particulars, throws a great deal of light on the relation between particulars and their attributes. -/- . (shrink)

This article examines peirce's technical use of metaphor. in doing so it looks at certain aspects of his semiotics and, in particular, his division of signs into icons, indexes, and symbols. the upshoot is that, for peirce, metaphor plays a central role in artistic thought while analogy is central to scientific thought.

This investigation joins recent research on problems with ambiguity in two fields, argumentation and computing. In argumentation, there is a concern with fallacies arising from ambiguity, including equivocation and amphiboly. In computing, the development of agent communication languages is based on conversation policies that make it possible to have information exchanges on the internet, as well as other forms of dialogue like persuasion and negotiation, in which ambiguity is a problem. Because it is not possible to sharply differentiate between problems (...) arising from ambiguity and those arising from vagueness, obscurity and indeterminacy, some study of the latter is included. The semantic web is based on what are called ontologies, or systems of classification of concepts, shown to be useful tools for dealing with these problems. (shrink)

The problem of when a recursive graph has a recursive k-coloring has been extensively studied by Bean, Schmerl, Kierstead, Remmel, and others. In this paper, we study the polynomial time analogue of that problem. We develop a number of negative and positive results about colorings of polynomial time graphs. For example, we show that for any recursive graph G and for any k, there is a polynomial time graph G′ whose vertex set is {0,1}* such that there is an effective (...) degree preserving correspondence between the set of k-colorings of G and the set of k-colorings of G′ and hence there are many examples of k-colorable polynomial time graphs with no recursive k-colorings. Moreover, even though every connected 2-colorable recursive graph is recursively 2-colorable, there are connected 2-colorable polynomial time graphs which have no primitive recursive 2-coloring. We also give some sufficient conditions which will guarantee that a polynomial time graph has a polynomial time or exponential time coloring. (shrink)

In the constructive theory of uniform spaces there occurs a technique of proof in which the application of a weak form of the law of excluded middle is circumvented by purely analytic means. The essence of this proof-technique is extracted and then applied in several different situations.

We examine the effective categoricity of equivalence structures via Ershov's difference hierarchy. We explore various kinds of categoricity available by distinguishing three different notions of isomorphism available in this hierarchy. We prove several results relating our notions of categoricity to computable equivalence relations: for example, we show that, for such relations, computable categoricity is equivalent to our notion of weak ω-c.e. categoricity, and that $\Delta _2^0 $ -categoricity is equivalent to our notion of graph-ω-c.e. categoricity.

The discussion of the Principle of Non-Contradiction (PNC) in Aristotle’s Metaphysics Γ is usually taken to include three ‘versions’ of the principle: an ontological, psychological, and logical one. In this article I develop an interpretation of Metaphysics Γ3 and a parallel text, De interpretatione 14, in order to show that these texts are concerned with two related but different principles: a version of the Principle of Identity, and a corollary to this, which concerns the ability to accept two ‘opposite’ items (...) at the same time. I argue that these principles must be considered separately in order to properly understand Aristotle’s remarks about PNC in Metaphysics Γ, and in order to defend his approach in these remarks against certain objections raised against the discussion in Metaphysics Γ by Jan Łukasiewicz in his "Über den Satz des Widerspruchs bei Aristoteles". The main result of my interpretation is to distinguish in the discussion of PNC in Metaphysics Γ three principles: one concerning linguistic items (words and statements), one concerning thoughts (δόξαι), and one concerning objects or states of affairs. (shrink)

Wilson introduces us to nine of his favorite authors through their lives, key works, and legacies. In doing so, he shows what good writing looks like-- and helps you become a better reader.

: Gandhi can serve as a valuable catalyst allowing us to rethink our philosophical positions on violence, nonviolence, and education. Especially insightful are Gandhi's formulations of the multidimensionality of violence, including educational violence, and the violence of the status quo. His peace education offers many possibilities for dealing with short-term violence, but its greatest strength is its long-term preventative education and socialization. Key to Gandhi's peace education are his ethical and ontological formulations of means-ends relations; the need to uncover root (...) causes and causal determinants and to free oneself from entrapment in escalating cycles of violence; and the dynamic complex relation between relative and absolute truth that includes analysis of situated embodied consciousness, tolerant diversity and inclusiveness, and an approach to unavoidable violence. (shrink)