Embryo adoption is a topic of considerable debate in the Church. Well over a million human embryos are currently being kept in cryogenic containers with little prospect of survival. The desire to rescue these vulnerable human beings is natural. However, the processes required to do so raise serious questions regarding the ethics of embryo adoptions. The violation of the unitive and procreative aspects of human intercourse and its ramifications on the moral status of heterologous embryo transfer are key to understanding (...) the reasoning behind some objections to human embryo adoption. (shrink)

Niccolo Machiavelli, one of the eminent minds of the Italian Renaissance, spent much of a long and active lifetime trying to determine and understand what exceptional qualities of human character-- and what surrounding elements of fortune, luck, and timing-- made great men great leaders successful in war and peace. In perhaps the liveliest book on Machiavelli in years, Michael A. Ledeen measures contemporary movers and doers against the timeless standards established by the great Renaissance writer. Titans of statecraft (Margaret (...) Thatcher, Francois Mitterrand, Pope John Paul II, Ronald Reagan, and Bill Clinton) business and finance (Bill Gates) Wall Street and investing (Warren Buffett) the military (Colin Powell), and sports (Michael Jordan) are judged by Machiavelli's precepts on leadership and the proper use of power. The result is a wide-ranging and scintillating study that illuminates the thoughts of the Renaissance master and the actions of today's truly towering figures as well as the character-challenged pretenders to greatness. Here is an exceptional book on Machiavelli and his ultra-realistic exploration of human nature-- then and now. (shrink)

ABSTRACT Persons injured as a result of exposure to toxic or carcinogenic substances are seldom able to recover damages from those who are responsible for the exposure. Tort law requires proof of causation, and causation is often unprovable because of long latency periods, because of the relative infrequency of the injuries and because many of the injuries among the exposed population are the result of other factors. A number of proposals for modifying the legal causation requirement to allow those who (...) create hazardous risks to be held liable for the injuries that materialise are considered and found inadequate. A proposal to treat risk exposure itself as an injury for which compensation under private law is possible is also considered and ultimately found incoherent. The paper concludes by arguing for a public law solution, modelled on criminal law, but providing compensation for victims. (shrink)

Universities and Colleges with a Christian affiliation have in recent years sought to renew and redefine their identities and almost all have rearticulated their mission for the modern age after a long and serious process of reappraisal. This process has been accompanied by an ongoing discussion of the nature and identity of higher education itself. This discussion has required leadership that is different from most secular leadership. This book provides a range of experienced voices, including the Archbishop of Canterbury, that (...) reflect on the character and mission of leadership in Christian higher education in the 21st Century. (shrink)

Under what conditions does a physical system implement or realize a computation? Structuralism about computational implementation, espoused by Chalmers and others, holds that a physical system realizes a computation just in case the system instantiates a pattern of causal organization isomorphic to the computation’s formal structure. I argue against structuralism through counter-examples drawn from computer science. On my opposing view, computational implementation sometimes requires instantiating semantic properties that outstrip any relevant pattern of causal organization. In developing my argument, I defend (...) anti-individualism about computational implementation: relations to the social environment sometimes help determine whether a physical system realizes a computation. 1 The Physical Realization Relation2 Semantics and Computational Implementation3 Conforming to Instructions4 Implementing a Computer Program4.1 The denotational semantics of Scheme4.2 Worries about intentionality4.3 Worries about the natural numbers5 Implementing a Machine Model6 Bounded Structuralism7 Triviality Arguments8 Anti-individualism about Computational Implementation. (shrink)

Fodor advocates a view of cognitive processes as computations defined over the language of thought (or Mentalese). Even among those who endorse Mentalese, considerable controversy surrounds its representational format. What semantically relevant structure should scientific psychology attribute to Mentalese symbols? Researchers commonly emphasize logical structure, akin to that displayed by predicate calculus sentences. To counteract this tendency, I discuss computational models of navigation drawn from probabilistic robotics. These models involve computations defined over cognitive maps, which have geometric rather than logical (...) structure. They thereby demonstrate the possibility of rational cognitive processes in an exclusively non-logical representational medium. Furthermore, they offer much promise for the empirical study of animal navigation. (shrink)

Alston, Searle, and Williamson advocate the restrictive model of assertion , according to which certain constitutive assertoric norms restrict which propositions one may assert. Sellars and Brandom advocate the dialectical model of assertion , which treats assertion as constituted by its role in the game of giving and asking for reasons. Sellars and Brandom develop a restrictive version of the dialectical model. I explore a non-restrictive version of the dialectical model. On such a view, constitutive assertoric norms constrain how one (...) must react if an interlocutor challenges one's assertion, but they do not constrain what one should assert in the first place. I argue that the non-restrictive dialectical perspective can accommodate various linguistic phenomena commonly taken to support the restrictive model. 1. (shrink)

Sensorimotor psychology studies the mental processes that control goal-directed bodily motion. Recently, sensorimotor psychologists have provided empirically successful Bayesian models of motor control. These models describe how the motor system uses sensory input to select motor commands that promote goals set by high-level cognition. I highlight the impressive explanatory benefits offered by Bayesian models of motor control. I argue that our current best models assign explanatory centrality to a robust notion of mental representation. I deploy my analysis to defend intentional (...) realism, to rebut eliminativism and instrumentalism regarding mental representation, and to explore the relation between intentionality and normativity. (shrink)

I argue that maps do not feature predication, as analyzed by Frege and Tarski. I take as my foil (Casati and Varzi, Parts and places, 1999), which attributes predication to maps. I argue that the details of Casati and Varzi’s own semantics militate against this attribution. Casati and Varzi emphasize what I call the Absence Intuition: if a marker representing some property (such as mountainous terrain) appears on a map, then absence of that marker from a map coordinate signifies absence (...) of the corresponding property from the corresponding location. Predication elicits nothing like the Absence Intuition. “F(a)” does not, in general, signify that objects other than a lack property F. On the basis of this asymmetry, I argue that attaching a marker to map coordinates is a different mode of semantic composition than attaching a predicate to a singular term. (shrink)

Lewis proved a Dutch book theorem for Conditionalization. The theorem shows that an agent who follows any credal update rule other than Conditionalization is vulnerable to bets that inflict a sure loss. Lewis’s theorem is tailored to factive formulations of Conditionalization, i.e. formulations on which the conditioning proposition is true. Yet many scientific and philosophical applications of Bayesian decision theory require a non-factive formulation, i.e. a formulation on which the conditioning proposition may be false. I prove a Dutch book theorem (...) tailored to non-factive Conditionalization. I also discuss the theorem’s significance. (shrink)

Conditionalization is a norm that governs the rational reallocation of credence. I distinguish between factive and non-factive formulations of Conditionalization. Factive formulations assume that the conditioning proposition is true. Non-factive formulations allow that the conditioning proposition may be false. I argue that non-factive formulations provide a better foundation for philosophical and scientific applications of Bayesian decision theory. I furthermore argue that previous formulations of Conditionalization, factive and non-factive alike, have almost universally ignored, downplayed, or mishandled a crucial causal aspect of (...) Conditionalization. To formulate Conditionalization adequately, one must explicitly address the causal structure of the transition from old credences to new credences. I offer a formulation of Conditionalization that takes these considerations into account, and I compare my preferred formulation with some prominent formulations found in the literature. (shrink)

I articulate and defend a new theory of what it is for a physical system to implement an abstract computational model. According to my descriptivist theory, a physical system implements a computational model just in case the model accurately describes the system. Specifically, the system must reliably transit between computational states in accord with mechanical instructions encoded by the model. I contrast my theory with an influential approach to computational implementation espoused by Chalmers, Putnam, and others. I deploy my theory (...) to illuminate the relation between computation and representation. I also rebut arguments, propounded by Putnam and Searle, that computational implementation is trivial. (shrink)

Turing computation over a non-linguistic domain presupposes a notation for the domain. Accordingly, computability theory studies notations for various non-linguistic domains. It illuminates how different ways of representing a domain support different finite mechanical procedures over that domain. Formal definitions and theorems yield a principled classification of notations based upon their computational properties. To understand computability theory, we must recognize that representation is a key target of mathematical inquiry. We must also recognize that computability theory is an intensional enterprise: it (...) studies entities as represented in certain ways, rather than entities detached from any means of representing them. (shrink)

Many philosophers worry that the classical computational theory of mind (CTM) engenders epiphenomenalism. Building on Block’s (1990) discussion, I formulate a particularly troubling version of this worry. I then present a novel solution to CTM’s epiphenomenalist conundrum. I develop my solution within an interventionist theory of causal relevance. My solution departs substantially from orthodox versions of CTM. In particular, I reject the widespread picture of digital computation as formal syntactic manipulation.1.

This paper discusses conditional probability $$P$$ P , or the probability of A given B. When $$P>0$$ P > 0 , the ratio formula determines $$P$$ P . When $$P=0$$ P = 0 , the ratio formula breaks down. The Borel–Kolmogorov paradox suggests that conditional probabilities in such cases are indeterminate or ill-posed. To analyze the paradox, I explore the relation between probability and intensionality. I argue that the paradox is a Frege case, similar to those that arise in many (...) probabilistic and non-probabilistic contexts. The paradox vividly illustrates how an agent’s way of representing an entity can rationally influence her credal assignments. I deploy my analysis to defend Kolmogorov’s relativistic treatment of conditional probability. (shrink)

This paper discusses how to update one’s credences based on evidence that has initial probability 0. I advance a diachronic norm, Kolmogorov Conditionalization, that governs credal reallocation in many such learning scenarios. The norm is based upon Kolmogorov’s theory of conditional probability. I prove a Dutch book theorem and converse Dutch book theorem for Kolmogorov Conditionalization. The two theorems establish Kolmogorov Conditionalization as the unique credal reallocation rule that avoids a sure loss in the relevant learning scenarios.

Dialectical egalitarianism holds that every asserted proposition requires defence when challenged by an interlocutor. This view apparently generates a vicious 'regress of justifications', since an interlocutor can challenge the premises through which a speaker defends her original assertion, and so on ad infinitum . To halt the regress, dialectical foundationalists such as Adler, Brandom, Leite, and Williams propose that some propositions require no defence in the light of mere requests for justification. I argue that the putative regress is not worrisome (...) and that egalitarianism can handle it quite satisfactorily. I also defend a positive view that combines an anti-foundationalist conception of dialectical interaction with a foundationalist conception of epistemic justification. (shrink)

Dialectical foundationalists, including Adler, Brandom, Leite, and Williams, claim that some asserted propositions do not require defense just because an interlocutor challenges them. By asserting such a proposition, the speaker shifts the burden of proof to her interlocutor. Dialectical egalitarians claim that all asserted propositions require defense when challenged. I elucidate the dispute between dialectical foundationalists and egalitarians, and I defend a broadly egalitarian stance against several prominent objections.

I critique an ancient argument for the possibility of non-linguistic deductive inference. The argument, attributed to Chrysippus, describes a dog whose behavior supposedly reflects disjunctive syllogistic reasoning. Drawing on contemporary robotics, I urge that we can equally well explain the dog's behavior by citing probabilistic reasoning over cognitive maps. I then critique various experimentally-based arguments from scientific psychology that echo Chrysippus's anecdotal presentation.

The perceptual system estimates distal conditions based upon proximal sensory input. It typically exploits information from multiple cues across and within modalities: it estimates shape based upon visual and haptic cues; it estimates depth based upon convergence, binocular disparity, motion parallax, and other visual cues; and so on. Bayesian models illuminate the computations through which the perceptual system combines sensory cues. I review key aspects of these models. Based on my review, I argue that we should posit co-referring perceptual representations (...) corresponding to distinct sensory cues. For example, the perceptual system represents a distal size using a representation canonically linked with vision and a distinct representation canonically linked with touch. Distinct co-referring perceptual representations represent the same denotation, but they do so under different modes of presentation. Bayesian cue combination models demonstrate that psychological explanation of perception should attend to mode of presentation and not simply to denotation. (shrink)

This chapter contains section titles: Insect Cognition The Science of Honeybee Navigation and Communication Representation and Truth‐Conditions Psychological Structure Pushmi‐Pullyu Representations Folk Psychology as an Explanatory Paradigm.

Interventionism is a theory of causal explanation developed by Woodward and Hitchcock. I defend an interventionist perspective on the causal explanations offered within scientific psychology. The basic idea is that psychology causally explains mental and behavioral outcomes by specifying how those outcomes would have been different had an intervention altered various factors, including relevant psychological states. I elaborate this viewpoint with examples drawn from cognitive science practice, especially Bayesian perceptual psychology. I favorably compare my interventionist approach with well-known nomological and (...) mechanistic theories of psychological explanation. (shrink)

The central philosophical task posed by conventions is to analyze what they are and how they differ from mere regularities of action and cognition. Subsidiary questions include: How do conventions arise? How are they sustained? How do we select between alternative conventions? Why should one conform to convention? What social good, if any, do conventions serve? How does convention relate to such notions as rule, norm, custom, practice, institution, and social contract? Apart from its intrinsic interest, convention is important because (...) philosophers frequently invoke it when discussing other topics. A favorite philosophical gambit is to argue that, perhaps despite appearances to the contrary, some phenomenon ultimately results from convention. Notable candidates include: property, government, justice, law, morality, linguistic meaning, necessity, ontology, mathematics, and logic. (shrink)

Church's thesis asserts that a number-theoretic function is intuitively computable if and only if it is recursive. A related thesis asserts that Turing's work yields a conceptual analysis of the intuitive notion of numerical computability. I endorse Church's thesis, but I argue against the related thesis. I argue that purported conceptual analyses based upon Turing's work involve a subtle but persistent circularity. Turing machines manipulate syntactic entities. To specify which number-theoretic function a Turing machine computes, we must correlate these syntactic (...) entities with numbers. I argue that, in providing this correlation, we must demand that the correlation itself be computable. Otherwise, the Turing machine will compute uncomputable functions. But if we presuppose the intuitive notion of a computable relation between syntactic entities and numbers, then our analysis of computability is circular. (shrink)

The formal conception of computation (FCC) holds that computational processes are not sensitive to semantic properties. FCC is popular, but it faces well-known difficulties. Accordingly, authors such as Block and Peacocke pursue a ?semantically-laden? alternative, according to which computation can be sensitive to semantics. I argue that computation is insensitive to semantics within a wide range of computational systems, including any system with ?derived? rather than ?original? intentionality. FCC yields the correct verdict for these systems. I conclude that there is (...) only one promising strategy for semantically-laden theorists: identify special computational systems that help generate their own semantic properties, and then show that computation within those systems is semantically-laden. Unfortunately, the few existing discussions that pursue this strategy are problematic. (shrink)

Conditionalization governs how to reallocate credence in light of new evidence. One prominent argument in favor of Conditionalization holds that an agent who violates it is vulnerable to a diachronic Dutch book: a series of acceptable bets offered at multiple times that inflict a sure loss. van Fraassen argues that an agent who violates the Principle of Reflection is likewise vulnerable to a diachronic Dutch book. He concludes that agents should conform to both Conditionalization and Reflection. Some authors reply that (...) Reflection is implausible and hence that there must be something wrong with diachronic Dutch book arguments. Other authors try to isolate a principled difference between the Dutch book argument for Conditionalization and the Dutch book argument for Reflection, such that the former argument may succeed even though the latter fails. I pursue a version of this strategy. I contend that, once we properly elucidate the notion of sure loss, non‐reflectors are not vulnerable to a sure loss. An agent who violates Reflection is not thereby subject to a diachronic Dutch book. Appearances to the contrary result from an unmotivated focus upon an overly narrow set of gambling scenarios. (shrink)

Many philosophers contend that Turing’s work provides a conceptual analysis of numerical computability. In (Rescorla, 2007), I dissented. I argued that the problem of deviant notations stymies existing attempts at conceptual analysis. Copeland and Proudfoot respond to my critique. I argue that their putative solution does not succeed. We are still awaiting a genuine conceptual analysis.

A striking thesis lies at the core of Davidson's philosophy: when we attribute intentional content to another creature's mental states and speech acts, we must treat the creature as largely conforming to our own rational norms. I will discuss how this thesis informs Davidson's treatment of rationality and intentionality. After reviewing some historical background, I present basic aspects of Davidson's position. I then examine various worries about the position. I conclude by highlighting some key Davidsonian insights into rationality.

This paper further develops the non-restrictive dialectical perspective. Many philosophers hold that truthfulness is somehow constitutive of assertion. I argue against this view while simultaneously attempting to ground truthfulness in assertion’s essential features. I argue that truthfulness is the prima facie best way to avoid decisive counter-arguments against what one says. Moreover, avoiding decisive counter-arguments is a constitutive goal of rational dialectic. Thus, while truthfulness is not constitutive of assertion, it is the rational default strategy for achieving a goal that (...) is constitutive of assertion. (shrink)

When P(E) > 0, conditional probabilities P(H|E)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(H|E)$$\end{document} are given by the ratio formula. An agent engages in ratio conditionalization when she updates her credences using conditional probabilities dictated by the ratio formula. Ratio conditionalization cannot eradicate certainties, including certainties gained through prior exercises of ratio conditionalization. An agent who updates her credences only through ratio conditionalization risks permanent certainty in propositions against which she has overwhelming evidence. To avoid this undesirable consequence, (...) I argue that we should supplement ratio conditionalization with Kolmogorov conditionalization, a strategy for updating credences based on propositions E such that P(E) = 0. Kolmogorov conditionalization can eradicate certainties, including certainties gained through prior exercises of conditionalization. Adducing general theorems and detailed examples, I show that Kolmogorov conditionalization helps us model epistemic defeat across a wide range of circumstances. (shrink)

A striking thesis lies at the core of Davidson‟s philosophy: when we attribute intentional content to another creature‟s mental states and speech acts, we must treat the creature as largely conforming to our own rational norms. I will discuss how this thesis informs Davidson‟s treatment of rationality and intentionality. After reviewing some historical background, I present basic aspects of Davidson‟s position. I then examine various worries about the position. I conclude by highlighting some key Davidsonian insights into rationality.

Fibroblast growth factors (FGFs) comprise a large family of developmental and physiological signaling molecules. All FGFs have a high affinity for the glycosaminoglycan heparin and for cell surface heparan sulfate proteoglycans. A large body of biochemical and cellular evidence points to a direct role for heparin/heparan sulfate in the formation of an active FGF/FGF receptor signaling complex. However, until recently there has been no direct demonstration that heparan is required for the biological activity of FGF in a developmental system in (...) vivo. A recent paper by Lin et al.(1) has broken through this barrier to demonstrate that heparan sulfate is essential for FGF function during Drosophila development. The establishment of a role for heparan sulfate in FGFR activation in vivo suggests that tissue-specific differences in the structure of heparan may modulate the activity of FGF. BioEssays 22:108–112, 2000. ©2000 John Wiley & Sons, Inc. (shrink)

In recent years, semiotics has become an innovative theoretical framework in mathematics education. The purpose of this article is to show that semiotics can be used to explain learning as a process of experimenting with and communicating about one's own representations of mathematical problems. As a paradigmatic example, we apply a Peircean semiotic framework to answer the question of how students learned the concept of "distribution" in a statistics course by "diagrammatic reasoning" and by developing "hypostatic abstractions," that is by (...) forming new mathematical objects which can be used as means for communication and further reasoning. Peirce's semiotic terminology is used as an alternative for notions such as modeling, symbolizing, and reification. We will show that it is a precise instrument of analysis with regard to the complexity of learning and of communication in mathematics classroom. (shrink)

An embodied movement-planning field cannot account for behavior and cognition more abstract than that of reaching. Instead, we propose an affordance field, and we sketch how it could enhance the analysis of the A-not-B error, underlie cognition, and serve as a base for language. Admittedly, a dynamic systems account of an affordance field awaits significant further development.

Standard models of cognition are built from abstract, amodal, arbitrary symbols, and the meanings of those symbols are given solely by their interrelations. The target article (Glenberg 1997t) argues that these models must be inadequate because meaning cannot arise from relations among abstract symbols. For cognitive representations to be meaningful they must, at the least, be grounded; but abstract symbols are difficult, if not impossible, to ground. As an alternative, the target article developed a framework in which representations are grounded (...) in perception and action, and hence are embodied. Recent work (Glenberg & Robertson 1999; 2000; Glenberg & Kaschak 2002; Kaschak & Glenberg 2000) extends this framework to language. (shrink)

The rapid sequencing of entire genomes based in large measure on a DNA cloning procedure, the polymerase chain reaction (PCR), has opened new frontiers in the discovery process for novel therapeutic agents. DNA cloning is a basic tool in genomics and it has been used for over a decade. Drug discovery is currently focused on the identification of gene databases, gene arrays and protein arrays aimed at therapeutic modulation of disease-related genes—which require procedures that may involve cloning techniques. Currently, cloning (...) for pharmacologic products is most applicable in the preclinical area of drug discovery. For example, the identification of specific receptor subtypes occurred via cloning whereas traditional pharmacologic approaches that use agonists and antagonists may have failed to separate binding affinities. Successful therapeutic agents where cloning played vital role resulted in the development of synthetic insulin, growth hormone, erythropoiten and other tissue factors in blood products, Vaccines may be another successful application derived from cloning. Another area where cloning can make a significant impact upon human therapeutics is that this technique may provide a new source of cells for tissue engineering and transplantation. Stem cells, and in particular, embryonic stem cells can differentiate into other cell types such as hepatocytes and neurons to provide normal products for hepatic and neurological diseases. However, the use of cloning embryonic stem cells introduces important ethical, medical and legal issues which require that leaders in government, academic, and religious groups be fully educated in these applications. A close working relationship among these diverse groups is needed to respond wisely to the introduction of new therapeutic opportunities while at the same time providing protection for the individual and the public at large from unethical practises. (shrink)

Pickering & Garrod's (P&G's) interactive alignment model explains the existence of alignment between speakers via an automatic priming mechanism. We propose that it may be preferable to explain alignment through processes of memory retrieval. Our discussion highlights how memory retrieval can produce the same results as the priming mechanism and presents data that favor the memory-based view.