Sensory substitution presents the philosopher of cognitive science with a particularly interesting case. Using prosthetics to map visual stimuli onto other modalities, such as touch or audition, otherwise blind individuals may develop perceptual capacities and behaviours commonly associated with sight. Experienced users can distinguish ‘visually’ presented objects and will even jerk back from a looming surface. Whether perception with sensory substitution devices should be classed as a type of vision, some other modality, or a new sense remains a matter of (...) debate, however. In the following, I review arguments commonly used to rebut the visual interpretation and, drawing on recent experimental studies and phenomenological self-reports, construct a novel case for treating sensory substitution as a visual process. (shrink)

The import of Hodgkin and Huxley’s classic model of the action potential has been hotly debated in recent years, with particular controversy surrounding claims by prominent proponents of mechanistic explanation. For these authors, the Hodgkin-Huxley model is an excellent predictive tool but ultimately lacks causal/explanatory import. What is more, they claim that this is how Hodgkin and Huxley themselves saw the model. I argue that these claims rest on a problematic reading of the work. Hodgkin and Huxley’s model is both (...) causal and, in an important sense, explanatory. (shrink)

This essay examines Ewald von Kleist’s 1745 invention of the Leyden jar using previously overlooked letters and features of his experimental apparatus to address lingering mysteries concerning the discovery. It has traditionally been claimed that Kleist unknowingly violated standard practice by grounding the device, the assumption being that this was the only way to obtain his remarkable results. In recent years, however, this interpretation has faced serious challenges, with experimental replications showing substantial shocks without grounding and period sources providing reason (...) to think that Kleist was insulated during the process. Supposing that Kleist was insulated raises puzzles of its own, however, as his results appear more extreme than such a charging method suggests. The missing piece, the author argues, is found in the unique nature of his setup. Drawing on established and novel sources, the essay shows how Kleist’s operation of his generator resulted in a closed circuit, explaining the strong charges cited by proponents of the traditional mistake narrative while upholding the absence of grounding. (shrink)

Current fears of a “reproducibility crisis” have led researchers, sources of scientific funding, and the public to question both the efficacy and trustworthiness of science. Suggested policy changes have been focused on statistical problems, such as p-hacking, and issues of experimental design and execution. However, “reproducibility” is a broad concept that includes a number of issues. Furthermore, reproducibility failures occur even in fields such as mathematics or computer science that do not have statistical problems or issues with experimental design. Most (...) importantly, these proposed policy changes ignore a core feature of the process of scientific inquiry that occurs after reproducibility failures: the integration of conflicting observations and ideas into a coherent theory. (shrink)

We introduce an atomic formula ${\vec{y} \bot_{\vec{x}}\vec{z}}$ intuitively saying that the variables ${\vec{y}}$ are independent from the variables ${\vec{z}}$ if the variables ${\vec{x}}$ are kept constant. We contrast this with dependence logic ${\mathcal{D}}$ based on the atomic formula = ${(\vec{x}, \vec{y})}$ , actually equivalent to ${\vec{y} \bot_{\vec{x}}\vec{y}}$ , saying that the variables ${\vec{y}}$ are totally determined by the variables ${\vec{x}}$ . We show that ${\vec{y} \bot_{\vec{x}}\vec{z}}$ gives rise to a natural logic capable of formalizing basic intuitions about independence and dependence. (...) We show that ${\vec{y} \bot_{\vec{x}}\vec{z}}$ can be used to give partially ordered quantifiers and IF-logic an alternative interpretation without some of the shortcomings related to so called signaling that interpretations using = ${(\vec{x}, \vec{y})}$ have. (shrink)

Guarded fragments of first-order logic were recently introduced by Andreka, van Benthem and Nemeti; they consist of relational first-order formulae whose quantifiers are appropriately relativized by atoms. These fragments are interesting because they extend in a natural way many propositional modal logics, because they have useful model-theoretic properties and especially because they are decidable classes that avoid the usual syntactic restrictions (on the arity of relation symbols, the quantifier pattern or the number of variables) of almost all other known decidable (...) fragments of first-order logic. Here, we investigate the computational complexity of these fragments. We prove that the satisfiability problems for the guarded fragment (GF) and the loosely guarded fragment (LGF) of first-order logic are complete for deterministic double exponential time. For the subfragments that have only a bounded number of variables or only relation symbols of bounded arity, satisfiability is EXPTIME-complete. We further establish a tree model property for both the guarded fragment and the loosely guarded fragment, and give a proof of the finite model property of the guarded fragment. It is also shown that some natural, modest extensions of the guarded fragments are undecidable. (shrink)

We identify the computational complexity of the satisfiability problem for FO 2 , the fragment of first-order logic consisting of all relational first-order sentences with at most two distinct variables. Although this fragment was shown to be decidable a long time ago, the computational complexity of its decision problem has not been pinpointed so far. In 1975 Mortimer proved that FO 2 has the finite-model property, which means that if an FO 2 -sentence is satisfiable, then it has a finite (...) model. Moreover, Mortimer showed that every satisfiable FO 2 -sentence has a model whose size is at most doubly exponential in the size of the sentence. In this paper, we improve Mortimer's bound by one exponential and show that every satisfiable FO 2 -sentence has a model whose size is at most exponential in the size of the sentence. As a consequence, we establish that the satisfiability problem for FO 2 is NEXPTIME-complete. (shrink)

It is a classical result of Mortimer that $L^2$ , first-order logic with two variables, is decidable for satisfiability. We show that going beyond $L^2$ by adding any one of the following leads to an undecidable logic:– very weak forms of recursion, viz.¶(i) transitive closure operations¶(ii) (restricted) monadic fixed-point operations¶– weak access to cardinalities, through the Härtig (or equicardinality) quantifier¶– a choice construct known as Hilbert's $\epsilon$ -operator.In fact all these extensions of $L^2$ prove to be undecidable both for satisfiability, (...) and for satisfiability in finite structures. Moreover most of them are hard for $\Sigma^1_1$ , the first level of the analytical hierachy, and thus have a much higher degree of undecidability than first-order logic. (shrink)

We show that the existential preservation theorem fails for two-variable first-order logic FO2. It is known that for all k ≥ 3, FOk does not have an existential preservation theorem, so this settles the last open case, answering a question of Andreka, van Benthem, and Németi. In contrast, we prove that the homomorphism preservation theorem holds for FO2.

We establish a general hierarchy theorem for quantifier classes in the infinitary logic L∞ωωon finite structures. In particular, it is shown that no infinitary formula with bounded number of universal quantifiers can express the negation of a transitive closure.This implies the solution of several open problems in finite model theory: On finite structures, positive transitive closure logic is not closed under negation. More generally the hierarchy defined by interleaving negation and transitive closure operators is strict. This proves a conjecture of (...) Immerman.We also separate the expressive power of several extensions of Datalog, giving new insight in the fine structure of stratified Datalog. (shrink)

In first order logic without equality, but with arbitrary relations and functions the ∃*∀∃* class is the unique maximal solvable prefix class. We show that the satisfiability problem for this class is decidable in deterministic exponential time The result is established by a structural analysis of a particular infinite subset of the Herbrand universe and by a polynomial space bounded alternating procedure.

This book gives a comprehensive overview of central themes of finite model theory – expressive power, descriptive complexity, and zero-one laws – together with selected applications relating to database theory and artificial intelligence, especially constraint databases and constraint satisfaction problems. The final chapter provides a concise modern introduction to modal logic, emphasizing the continuity in spirit and technique with finite model theory. This underlying spirit involves the use of various fragments of and hierarchies within first-order, second-order, fixed-point, and infinitary logics (...) to gain insight into phenomena in complexity theory and combinatorics. The book emphasizes the use of combinatorial games, such as extensions and refinements of the Ehrenfeucht-Fraissé pebble game, as a powerful way to analyze the expressive power of such logics, and illustrates how deep notions from model theory and combinatorics, such as o-minimality and treewidth, arise naturally in the application of finite model theory to database theory and AI. Students of logic and computer science will find here the tools necessary to embark on research into finite model theory, and all readers will experience the excitement of a vibrant area of the application of logic to computer science. (shrink)

Motivated by the search for a logic for polynomial time, we study rank logic which extends fixed-point logic with counting by operators that determine the rank of matrices over finite fields. WhileFPRcan express most of the known queries that separateFPCfromPtime, almost nothing was known about the limitations of its expressive power.In our first main result we show that the extensions ofFPCby rank operators over different prime fields are incomparable. This solves an open question posed by Dawar and Holm and also (...) implies that rank logic, in its original definition with a distinct rank operator for every field, fails to capture polynomial time. In particular we show that the variant of rank logic${\text{FPR}}^{\text{*}}$with an operator that uniformly expresses the matrix rank over finite fields is more expressive thanFPR.One important step in our proof is to consider solvability logicFPSwhich is the analogous extension ofFPCby quantifiers which express the solvability problem for linear equation systems over finite fields. Solvability logic can easily be embedded into rank logic, but it is open whether it is a strict fragment. In our second main result we give a partial answer to this question: in the absence of counting, rank operators are strictly more expressive than solvability quantifiers. (shrink)

We design functional algebras that characterize various complexity classes of global functions. For this purpose, classical schemata from recursion theory are tailored for capturing complexity. In particular we present a functional analog of first-order logic and describe algebras of the functions computable in nondeterministic logarithmic space, deterministic and nondeterministic polynomial time, and for the functions computable by AC 1 -circuits.

In the past two to three decades health behavior scientists have increasingly emphasized affect-related concepts (including, but not limited to emotion) in their attempts to understand and facilitate change in important health behaviors, such as smoking, eating, physical activity, substance abuse, and sex. This article provides a narrative review of this burgeoning literature, including relevant theory and research on affective response (e.g., hedonic response to eating and drug use), incidental affect (e.g., work-related stress as a determinant of alcohol use), affect (...) processing (e.g., anticipated regret for illicit sex or skipping an exercise session), and affectively charged motivation (e.g., cigarette craving). An integrative dual-processing framework is presented that suggests pathways through which affect-related concepts may interrelate to influence health behavior. (shrink)

Book reviewed in this article: For the Patient's Good: The Restoration of Beneficence in Health Care. By Edmund D. Pellegrino and David C. Thomasma.

The two main psychological theories of the ordinary conditional were designed to account for inferences made from assumptions, but few premises in everyday life can be simply assumed true. Useful premises usually have a probability that is less than certainty. But what is the probability of the ordinary conditional and how is it determined? We argue that people use a two stage Ramsey test that we specify to make probability judgements about indicative conditionals in natural language, and we describe experiments (...) that support this conclusion. Our account can explain why most people give the conditional probability as the probability of the conditional, but also why some give the conjunctive probability. We discuss how our psychological work is related to the analysis of ordinary indicative conditionals in philosophical logic. (shrink)

Within any organization (e.g. a hospital or clinic) the perception of the way things operate may vary dramatically as a function of one’s location in the organizational hierarchy as well as one’s professional discipline. Interorganizational variability depends on organizational coherence, safety, and stability. In this four-nation (Canada, Ireland, Australia, and Korea) qualitative study of 42 nurses, we explored their perception of how ethical decisions are made, the nurses’ hospital role, and the extent to which their voices were heard. These nurses (...) suggested that their voices were silenced (often voluntarily) or were not expressed in terms of ethical decision making. Finally, they perceived that their approach to ethical decision making differed from physicians. (shrink)

A detailed multi-disciplinary analysis of Sudan in the post-colonial era with a consideration of possibilities for the future.

One persistent challenge in scientific practice is that the structure of the world can be unstable: changes in the broader context can alter which model of a phenomenon is preferred, all without any overt signal. Scientific discovery becomes much harder when we have a moving target, and the resulting incorrect understandings of relationships in the world can have significant real-world and practical consequences. In this paper, we argue that it is common (in certain sciences) to have changes of context that (...) lead to changes in the relationships under study, but that standard normative accounts of scientific inquiry have assumed away this problem. At the same time, we show that inference and discovery methods can “protect” themselves in various ways against this possibility by using methods with the novel methodological virtue of “diligence.” Unfortunately, this desirable virtue provably is incompatible with other desirable methodological virtues that are central to reliable inquiry. No scientific method can provide every virtue that we might want. (shrink)

Mestre, MacCann, Guil, and Roberts propose a model that suggests emotion regulation provides the mechanism through which ability emotional intelligence influences important outcomes. We argue that important nuance in our understanding of people’s choice of emotion regulation strategy can be gained by incorporating personality constructs such as trait emotional intelligence within this model.

Structure learning algorithms for graphical models have focused almost exclusively on stable environments in which the underlying generative process does not change; that is, they assume that the generating model is globally stationary. In real-world environments, however, such changes often occur without warning or signal. Real-world data often come from generating models that are only locally stationary. In this paper, we present LoSST, a novel, heuristic structure learning algorithm that tracks changes in graphical model structure or parameters in a dynamic, (...) real-time manner. We show by simulation that the algorithm performs comparably to batch-mode learning when the generating graphical structure is globally stationary, and significantly better when it is only locally stationary. (shrink)

Book reviewed in this article: Suffering and the Beneficent Community: Beyond Libertarianism. By Erich H. Loewy. The Nature of Suffering and the Goals of Medicine. By Eric J. Cassell.

From time to time medical ethicists bemoan the loss of a religious perspective in medical ethics. The discipline had its origins in the thinking of explicitly religious thinkers such as Paul Ramsey and Joseph Fletcher. Furthermore, many of those who contributed to the early development of the discipline had training in theology. One thinks of Daniel Callahan, Richard McCormick, Albert Jonsen, Sam. Banks. As the discipline becomes more and more self-reflective, with attention being paid to methodological and conditional concerns, it (...) is only natural that the roots are due for a reexamination. The time has therefore come for some reassessment. The first steps here are taken in the form of a dialogue between the coauthors to clarify authentic contributions and weed out unauthentic ones. (shrink)

At the end of the most violent century in human history, it is good to take stock of our commitments to human and other life forms, as well as to examine the rights and the duties that might flow from their biological makeup. Professor Thomasma and Professor Loewy have held a long-standing dialogue on whether there are moral differences between animals and humans. This dialogue was occasioned by a presentation Thomasma made some years ago at Loewy's invitation at the University (...) of Illinois, Peoria, Medical Center. During that presentation, Thomasma argued that human beings are sufficiently distinct from other animals genetically and otherwise to justify a moral difference in rights and obligations. In effect, he argued that there are species-specific rights. This essay will pick up the threads of that dialogue. (shrink)

Here we explore, through conversation, our experience, as programme coordinators, of delivering degree-level apprenticeships. Although relatively ‘young’, the Degree Apprenticeship model has grown significantly since its inception in 2015 and such programmes continue to be supported politically in a way which suggests a long-term future. However, our experience has been one where two different domains of practice have collided—that of ‘Higher Education’ and that of ‘Apprenticeship’—in a way which, for us, has not been comfortable.Our conversation explores the issues of working (...) within a triangular relationship between apprentice, employer and the university, in the context of the Apprenticeship framework in England. In addition, the idea of apprenticeship and work-based learning is considered from our direct experience as we reflect on how our current teaching practice has been informed by our early careers. Grounded by the notion of an apprenticeship ideal that is supposed to exist, we consider the apparent tensions that are inherent in offering apprenticeships within a university context. (shrink)

We propose a domain-level ontology of plays for the facilitation of play-based collaborative autonomy among unmanned and manned-unmanned aircraft teams in the Army’s Unmanned Aircraft System (UAS) mission domain. We define a play as a type of plan that prescribes some pattern of intentional acts that are intended to reliably result in some goal in some competitive context, and which specifies one or more roles that are realized by those prescribed intentional acts. The ontology is well suited to be extended (...) to other types of military and nonmilitary unmanned vehicle operations. (shrink)