Online educational technologies offer opportunities for providing individualized feedback and detailed profiles of students' skills. Yet many technologies for mathematics education assess students based only on the correctness of either their final answers or responses to individual steps. In contrast, examining the choices students make for how to solve the equation and the ways in which they might answer incorrectly offers the opportunity to obtain a more nuanced perspective of their algebra skills. To automatically make sense of step‐by‐step solutions, we (...) propose a Bayesian inverse planning model for equation solving that computes an assessment of a learner's skills based on her pattern of errors in individual steps and her choices about what sequence of problem‐solving steps to take. Bayesian inverse planning builds on existing machine learning tools to create a generative model relating (mis)‐understandings to equation solving choices. Two behavioral experiments demonstrate that the model can interpret people's equation solving and that its assessments are consistent with those of experienced teachers. A third experiment uses this model to tailor guidance for learners based on individual differences in misunderstandings, closing the loop between assessing understanding, and using that assessment within an educational technology. Finally, because the bottleneck in applying inverse planning to a new domain is in creating the model of possible student misunderstandings, we show how to combine inverse planning with an existing production rule model to make inferences about student misunderstandings of fraction arithmetic. (shrink)

This book attempts to resolve some of the oldest and most bitter controversies between the Eastern and Western Christian churches: those concerning the doctrine of God, the nature of salvation, and theological method, all of which converge in the doctrine of deification. Deification was the dominant patristic model of salvation and remained the essential paradigm in the East but was thought to have disappeared from Western theology by the Middle Ages. A. N. Williams examines two key thinkers, each of whom (...) is championed as the authentic spokesman of his own tradition and reviled by the other side. Taking Thomas Aquinas as representative of the West and Gregory Palamas for the East, she presents fresh readings of their work that both reinterpret each thinker and show an area of commonality between them much greater than has previously been acknowledged. (shrink)

There are many important methodological decisions that need to be made when examining emotional reactivity in psychopathology. In the present study, we examined the effects of two such decisions in an investigation of emotional reactivity in depression: (1) which (if any) comparison condition to employ; and (2) how to define change. Depressed (N = 69) and control (N = 37) participants viewed emotion-inducing film clips while subjective and facial responses were measured. Emotional reactivity was defined using no comparison condition (i.e., (...) raw scores), baseline comparison condition (i.e., no stimulus presented), and neutral comparison condition (i.e., neutral stimulus presented). Change in emotional reactivity was assessed using four analytic approaches: difference scores, percentage change, residualised change, and ANCOVA. Results differed among the three comparison conditions and among several of the analytic approaches. Overall, our investigation suggests that choosing a comparison condition and the definition of change can significantly influence the presence of group differences in emotional reactivity. Recommendations for studies of emotional reactivity in psychopathology are discussed. (shrink)

Eyewitnesses are often susceptible to recollection failures and memory distortions. These failures and distortions are influenced by several factors. The present review will discuss two such important factors, attention failures and stress. We argue that acute stress, often experienced by eyewitnesses and victims of crimes, directly influences attentional processes, which likely has downstream consequences for memory. Attentional failures may result in individuals missing something unusual or important in a complex visual field. Amongst eyewitnesses, this can lead to individuals missing details, (...) even unusual or important central details, regarding the crime. Surprisingly, few studies have investigated attentional failures in eyewitness scenarios, and none have investigated the relationship between stress, attention, and witness memory. This review will discuss the impact of attentional failures, mainly those resulting from inattentional blindness, in applied contexts in order to bridge to eyewitness scenarios. In addition, we will integrate the applied literature on attentional failures with literature that examines the influences of arousal and stress on attention. We will conclude by presenting how future research may tease apart the independent contributions of arousal and stress on attentional failures and successes and how this research may inform understanding of eyewitness reliability. (shrink)

Rudolf Kjellén, regularly referred to as "the father of geopolitics," developed in the first decade of the twentieth century an analytical model for calculating the capabilities of great-power states and promoting their interests in the international arena. It was an ambitious intellectual project that sought to bring politics into the sphere of social science. Bringing together experts on Kjellén from across the disciplines, Territory, State and Nation explores the century-long international impact, analytical model, and historical theories of a figure immensely (...) influential in his time who is curiously little-known today. (shrink)

Denys Turner argues that there are reasons of faith why the existence of God should be thought rationally demonstrable and that it is worthwhile revisiting the theology of Thomas Aquinas to see why. The proposition that the existence of God is demonstrable by rational argument is doubted by nearly all philosophical opinion today and is thought by most Christian theologians to be incompatible with Christian faith. Turner's robust challenge to the prevailing orthodoxies will be of interest to believers as (...) well as non-believers. (shrink)

Given any proposition, is it possible to have rationally acceptable attitudes towards it? Absent reasons to the contrary, one would probably think that this should be possible. In this paper I provide a reason to the contrary. There is a proposition such that, if one has any opinions about it at all, one will have a rationally unacceptable set of propositional attitudes—or if one doesn’t, one will end up being cognitively imperfect in some other manner. The proposition I am concerned (...) with is a self-referential propositional attitude ascription involving the propositional attitude of rejection. Given a basic assumption about what constitutes irrationality, and a few assumptions about the nature of cognitively ideal agents, a paradox results. This paradox is superficially like the Liar, but it is importantly different in that no alethic notions are involved at all. As such, it stands independent of the Liar and is not a ‘revenge’ version of it. After setting out the paradox I discuss possible responses. After considering several I argue that one is best off simply accepting that the paradox shows us something surprising and interesting about rationality: that some cognitive shortfall is unavoidable even for ideal agents. I argue that nothing disastrous follows from accepting this conclusion. (shrink)

Antonio Argandoña, Norbert Bilbeny, Victòria Camps, Miquel Calsina, Àngel Castiñeira, Cristian Palazzi, Ferran Requejo, Raimon Ribera, Begoña Román, Ferran Sàez, Miquel Seguró, Francesc Torralba, Josep Maria Vallès, Rosamund Thomas Ramon Llull Journal of Applied Ethics 2012 3(3):9-16.

The third volume of The History of European Philosophy in the Fifteenth Century deals with the question of "being." In the closing paragraph, Stefan Swiezawski remarks: "Studies on the transformation and distortion of St. Thomas's doctrine on being, especially in regard to its existential element, are fundamentally important for understanding the factual historical development of Thomism as well as for understanding modern Christian thought. They are also of utmost importance for understanding the mainspring and resultant trends which have shaped (...) the direction of philosophical reflection in Europe during the last several centuries". The fourth volume of his opus magnum under review here, touches upon the problematics of God. It is this volume which serves as the best example of all those deviations and distortions which come from a mistreatment of the philosophy of being. Moreover, fifteenth century philosophy, in the disguise of metaphysics, can be seen as "a century of theology which in a more differentiated form and restless way" professed and used "pluralism of the conception of theology as a science". (shrink)

When some P implies some Q, this should have some impact on what attitudes we take to P and Q. In other words: logical consequence has a normative import. I use this idea, recently explored by a number of scholars, as a stepping stone to a bolder view: that relations of logical consequence can be identified with norms on our propositional attitudes, or at least that our talk of logical consequence can be explained in terms of such norms. I investigate (...) the prospects of such a cognitive norm account of logical consequence. I go over the challenges involved in finding a plausible bridge principle connecting logical consequence to cognitive norms, in particular a biconditional principle that gives us not only necessary but sufficient conditions for logical consequence in terms of norms on propositional attitudes. Then, on the assumption that an adequate norm can be found, I consider what the philosophical merits of such a cognitive norm account would be, and what theoretical commitments it would generate. (shrink)

What determines whether an object is an artwork? In this paper I consider what I will call ‘social’ theories of art, according to which the arthood of objects depends in some way on the art-related social practices that we have. Though such a dependence claim is plausible in principle, social theories of art tend to unpack the determining link between artworks and social practices in terms of intentional relations between the objects in question and the people involved in the relevant (...) practices. This intentionalism has unappealing upshots. Drawing on two-dimensional approaches in social ontology, I show how social theories of art can be done differently, improving their prospects. (shrink)

What determines whether an object is an artwork? In this paper I consider what I will call ‘social’ theories of art, according to which the arthood of objects depends in some way on the art-related social practices that we have. Though such a dependence claim is plausible in principle, social theories of art tend to unpack the determining link between artworks and social practices in terms of intentional relations between the objects in question and the people involved in the relevant (...) practices. This intentionalism has unappealing upshots. Drawing on two-dimensional approaches in social ontology, I show how social theories of art can be done differently, improving their prospects. (shrink)

Niche construction refers to the activities of organisms that bring about changes in their environments, many of which are evolutionarily and ecologically consequential. Advocates of niche construction theory (NCT) believe that standard evolutionary theory fails to recognize the full importance of niche construction, and consequently propose a novel view of evolution, in which niche construction and its legacy over time (ecological inheritance) are described as evolutionary processes, equivalent in importance to natural selection. Here, we subject NCT to critical evaluation, in (...) the form of a collaboration between one prominent advocate of NCT, and a team of skeptics. We discuss whether niche construction is an evolutionary process, whether NCT obscures or clarifies how natural selection leads to organismal adaptation, and whether niche construction and natural selection are of equivalent explanatory importance. We also consider whether the literature that promotes NCT overstates the significance of niche construction, whether it is internally coherent, and whether it accurately portrays standard evolutionary theory. Our disagreements reflect a wider dispute within evolutionary theory over whether the neo-Darwinian synthesis is in need of reformulation, as well as different usages of some key terms (e.g., evolutionary process). (shrink)

Environmental ethicists have frequently criticized ancient Greek philosophy as anti-environmental for a view of philosophy that is counterproductive to environmental ethics and a view of the world that puts nature at the disposal of people. This provocative collection of original essays reexamines the views of nature and ecology found in the thought of Plato, Aristotle, the Stoics, and Plotinus. Recognizing that these thinkers were not confronted with the environmental degradation that threatens contemporary philosophers, the contributors to this book find that (...) the Greeks nevertheless provide an excellent foundation for a sound theory of environmentalism. (shrink)

When making decisions, humans can observe many kinds of information about others' activities, but their effects on performance are not well understood. We investigated social learning strategies using a simple problem-solving task in which participants search a complex space, and each can view and imitate others' solutions. Results showed that participants combined multiple sources of information to guide learning, including payoffs of peers' solutions, popularity of solution elements among peers, similarity of peers' solutions to their own, and relative payoffs from (...) individual exploration. Furthermore, performance was positively associated with imitation rates at both the individual and group levels. When peers' payoffs were hidden, popularity and similarity biases reversed, participants searched more broadly and randomly, and both quality and equity of exploration suffered. We conclude that when peers' solutions can be effectively compared, imitation does not simply permit scrounging, but it can also facilitate propagation of good solutions for further cumulative exploration. (shrink)

When searching for concepts in memory—as in the verbal fluency task of naming all the animals one can think of—people appear to explore internal mental representations in much the same way that animals forage in physical space: searching locally within patches of information before transitioning globally between patches. However, the definition of the patches being searched in mental space is not well specified. Do we search by activating explicit predefined categories and recall items from within that category, or do we (...) activate and recall a connected sequence of individual items without using categorical information, with each item recalled leading to the retrieval of an associated item in a stream, or both? Using semantic representations in a search of associative memory framework and data from the animal fluency task, we tested competing hypotheses based on associative and categorical search models. Associative, but not categorical, patch transitions took longer to make than position-matched productions, suggesting that categorical transitions were not true transitions. There was also clear evidence of associative search even within categorical patch boundaries. Furthermore, most individuals' behavior was best explained by an associative search model without the addition of categorical information. Thus, our results support a search process that does not use categorical information, but for which patch boundaries shift with each recall and local search is well described by a random walk in semantic space, with switches to new regions of the semantic space when the current region is depleted. (shrink)

Do our lives have meaning? Should we create more people? Is death bad? Should we commit suicide? Would it be better to be immortal? Should we be optimistic or pessimistic? Since Life, Death, and Meaning: Key Philosophical Readings on the Big Questions first appeared, David Benatar's distinctive anthology designed to introduce students to the key existential questions of philosophy has won a devoted following among users in a variety of upper-level and even introductory courses.

The inventor of the concepts of emics and etics, linguist Kenneth Pike, uses this volume as a forum to explain their development and their usage today. He is joined in the debate by renowned anthropologist Marvin Harris. Eight other scholars add to the scholarly discourse and demonstrate applications of the concepts in a variety of disciplines. Referring to insider versus outsider, subjective versus objective views of the world, these concepts are vital for researchers dealing with cultures other than their own.

We compared the ability of three different contextual models of lexical semantic memory and of a simple associative model to predict the properties of semantic networks derived from word association norms. None of the semantic models were able to accurately predict all of the network properties. All three contextual models over-predicted clustering in the norms, whereas the associative model under-predicted clustering. Only a hybrid model that assumed that some of the responses were based on a contextual model and others on (...) an associative network successfully predicted all of the network properties and predicted a word's top five associates as well as or better than the better of the two constituent models. The results suggest that participants switch between a contextual representation and an associative network when generating free associations. We discuss the role that each of these representations may play in lexical semantic memory. Concordant with recent multicomponent theories of semantic memory, the associative network may encode coordinate relations between concepts, and contextual representations may be used to process information about more abstract concepts. (shrink)

Originally published in 1963, this classic book is a rethinking of the history of Western political philosophy. Charles N. R. McCoy contrasts classical-medieval principles against the "hypotheses" at the root of modern liberalism and modern conservativism. In Part I, "The Classical Christian Tradition from Plato to Aquinas," the author lays the foundation for a philosophical "structure" capable of producing "constitutional liberty." Part II, "The Modern Theory of Politics from Machiavelli to Marx," attempts to show, beginning with Machiavelli, the reversal and (...) destruction of the pre-modern "structure" postulated in Part I. McCoy stresses the great contributions of Aristotle to political thought found in his more familiar Ethics and Politics, but also includes key insights drawn from Metaphysics and Physics. These contributions are developed and perfected, McCoy argues, by Augustine and Aquinas. Two other important features include McCoy's epistemological insights into Plato's work that will be new to many readers and the author's juxtaposition of traditional natural law with "the modernized theory of natural law." The modern account of autonomous natural law, in McCoy's view, helps explain the totalitarian direction of key aspects of modern political thought. This classic volume on the origins of modern philosophical thought remains a standard in the field. (shrink)

In his “A New Program for Philosophy of Science?”, Ronald Giere expresses qualms regarding the critical and political projects I advocate for philosophy of science—that the critical project assumes an underdetermination absent from actual science, and the political project takes us outside the professional pursuit of philosophy of science. In reply I contend that the underdetermination the critical project assumes does occur in actual science, and I provide a variety of examples to support this. And I contend that the political (...) project requires no more than what other academic fields even in science studies are already providing. (shrink)

In “Avoiding a Death Panel Redux,” Nicole Piemonte and Laura Hermer make the argument that the advance care planning consultation provision during the health care reform debate collapsed both because the language in the provision was deliberately misread and because some features of the language could in fact be misleading. We agree on both counts. We add that the cost‐effectiveness provisions of the bill make us face difficult decisions we as a nation would rather avoid, but can and must face (...) squarely and together. It is time for an honest national conversation about at least two issues concerning medical care near the end of life. First, talking about or planning a good death with your doctor or nurse will not make death happen sooner. The data show that better planning for a well‐managed terminal illness leads to longer life as well as better symptom control and less distress. Second, we need to quickly and directly confront the cost of end of life care in the United State, recognize the political consequences, and work with the broad middle to advance the common good. (shrink)

_A history of the world’s first democracy from its beginnings in Athens circa fifth century B.C. to its downfall 200 years later_ The first democracy, established in ancient Greece more than 2,500 years ago, has served as the foundation for every democratic system of government instituted down the centuries. In this lively history, author Thomas N. Mitchell tells the full and remarkable story of how a radical new political order was born out of the revolutionary movements that swept through (...) the Greek world in the seventh and sixth centuries B.C., how it took firm hold and evolved over the next two hundred years, and how it was eventually undone by the invading Macedonian conquerors, a superior military power. Mitchell’s superb history addresses the most crucial issues surrounding this first paradigm of democratic governance, including what initially inspired the political beliefs underpinning it, the ways the system succeeded and failed, how it enabled both an empire and a cultural revolution that transformed the world of arts and philosophy, and the nature of the Achilles heel that hastened the demise of Athenian democracy. (shrink)

A key source of support for the view that challenging people’s beliefs about free will may undermine moral behavior is two classic studies by Vohs and Schooler (2008). These authors reported that exposure to certain prompts suggesting that free will is an illusion increased cheating behavior. In the present paper, we report several attempts to replicate this influential and widely cited work. Over a series of five studies (sample sizes of N = 162, N = 283, N = 268, N (...) = 804, N = 982) (four preregistered) we tested the relationship between (1) anti-free-will prompts and free will beliefs and (2) free will beliefs and immoral behavior. Our primary task was to closely replicate the findings from Vohs and Schooler (2008) using the same or highly similar manipulations and measurements as the ones used in their original studies. Our efforts were largely unsuccessful. We suggest that manipulating free will beliefs in a robust way is more difficult than has been implied by prior work, and that the proposed link with immoral behavior may not be as consistent as previous work suggests. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Criminal Law, Pain Relief, and Physician Aid in DyingFaye Girsh, Ed.D., Executive DirectorMadam:The article by Cantor and Thomas on “Pain Relief, Acceleration of Death, and Criminal Law” (KIEJ, June 1996) was a tortured attempt to develop criteria for the humane and compassionate physician who tries to serve the needs of a patient in unremitting pain. There are three areas that merit comment.The authors dealt with pain medications that (...) might have the undesirable side effect of causing death. They did not mention tolerance, which usually occurs in a patient with chronic pain and which would require exceedingly high doses to be effective. They did not mention barbiturates, which are preferable to opiates in causing death and which are used increasingly by compassionate physicians to answer the pleas of their suffering patients, but for which there is no excuse about alleviating pain. Would the criminal law just call the prescription of a lethal dose of barbiturates a reckless act and require conviction? Fortunately, juries, as the authors point out, do not balance these formulas on the head of a pin. When they see the circumstances under which these doctors do help their patients, they choose to nullify the law and would ignore the suggestions made in this article.The authors refer to the “consent” of the patient. They do not mention that these doctors are operating with more than consent; they are administering these medications because suffering patients are begging them to put them out of their pain and the indignities of the dying process. The article discusses the process as though it were the same as consent to elective surgery. These patients—with AIDS, cancer, and hopeless neurological degeneration—are not simply agreeing to a procedure; they are desperately seeking a way out. If the criminal law were to develop criteria for physician aid in dying, certainly one of them should be the active, witnessed, repeated request of such a patient for a certain, quick, painless, gentle death.The third point is that physicians do not face prosecution when administering no treatment to a patient whose life could be saved with treatment but who chooses not to receive it. This has been upheld by the U.S. Supreme Court; no criteria for suffering, alternatives, terminality, justifiability, or unbearability are required. The doctor can stand by while the patient dies what may be a protracted, difficult death, but it is within the law. What matters in this situation is the decision of the patient to refuse treatment, and that is absolute. How ironic that the patient who cannot refuse treatment must, with his or her doctor, jump through all these hoops to achieve a peaceful death.One worries that the physician who must balance the risk of “risky pain relief” against the accusation of recklessness will err in the direction of allowing [End Page 103] the patient to bear the pain rather than help with a dose of analgesics that might be considered beyond the stipulated “risk.”Why don’t we just be honest about it? Allow dying or hopelessly ill patients to make the decision about what they want by passing a carefully defined law allowing euthanasia rather than balancing the risk and trying to determine the “purpose” of the physician’s ministrations. We protect some patients from themselves while allowing others almost complete autonomy to make the choice of ending their lives. The authors were right in saying that proponents of rational laws consider this sheer hypocrisy.Faye Girsh, Executive DirectorHemlock Society U.S.A. Denver, COFaye Girsh misconceives our article’s objective as an “attempt to develop criteria” for the humane physician. Our goal in writing the paper was to analyze the current criminal law framework in the hope of sharpening debate and engendering normative critiques. We readily acknowledge tensions in the current legal framework and would support changes in that framework.Copyright © 1997 The Johns Hopkins University Press... (shrink)

Biomass provides the only sustainable source of organic carbon for the production of chemicals used in manufacturing and as liquid transportation fuels. In this article, the authors examine some of the challenges that society faces in the transition from a global economy in which transportation fuels are derived from fossil fuels to one in which they are derived from renewable biomass via a “biorefinery.” In so doing, the authors present an overview of the technology currently available to society and highlight (...) some of the key issues that must be resolved in order to grasp the opportunities that stem from the transition. They conclude by considering the situation of their own country, Australia, to illustrate that the solutions to the challenges will likely depend not only on technology development but also on social, political, and geographical factors. (shrink)

With the Reformation, philosophers sought to establish a new way of thinking independent of religion. Borrowing principles popularized religious reformers: the right of conscience, the utter transcendence of God, the sinfulness of the world, they constructed a new metaphysics that highlighted the mystery of God and the complete intelligibility of 'rational man.' From this history an understanding of our religious situation is distilled. The chapters of this work develop for the reader the intellectual structure of religion and show how its (...) language, imagery and ritual function. They argue that if religion no longer presents a challenge, it is because we think of it in terms of the 'new metaphysics.' To recapture the reality, we must join our contemporaries who are attacking the premises of classical modern philosophy and so experience ourselves afresh. (shrink)

Thomas A. Fay Heidegger and the Formalization of Thought 1 Dagfinn F011esdal The Justification of Logic and Mathematics in Husserl's Phenomenology 25 Guillermo E. Rosado Haddock On Husserl's Distinction between State of Affairs and Situation of Affairs.... 35 David Woodruff Smith On Situations and States of Affairs 49 Charles W. Harvey, Jaakko Hintikka Modalization and Modalities................... 59 Gilbert T. Null Remarks on Modalization and Modalities 79 J. N. Mohanty Husserl's Formalism 93 Carl J. Posy Mathematics as a Transcendental Science (...) 107 vi Gian-carlo Rota Mathematics and the Task of Phenomenology 133 John Scalon "Tertium Non Datur: " Husserl's Conception of a Definite Multiplicity..... 139 Thomas M. Seebohm Psychologism Revisited 149 Gerald J. Massey Some Reflections on Psychologism 183 Robert S. Tragesser How Mathematical Foundation all but come about: A Report on Studies Toward a Phenomenological Critique of Godel's Views on Mathematical Intuition.. 195 Kenneth L. Manders On Geometric Intentionality 215 Dallas Willard Sentences which are True in Virtue of their Color... 225 John J. Drummond Willard and Husserl on Logical Form 243 Index of Names 257 Index of Subjects 259 PREFACE The phenomenology of logic and ideal objects is the topic of Husserl's Logical Investigations. This book determined the early development of the so called phenomenological movement. It is still the main source for many phenomenologists, even if they disagree with Husserl's transcendental turn and developed other phenomenological positions or positions beyond phenomenology he early sense. (shrink)

We have synthesized a 582,970-base pair Mycoplasma genitalium genome. This synthetic genome, named M. genitalium JCVI-1.0, contains all the genes of wild-type M. genitalium G37 except MG408, which was disrupted by an antibiotic marker to block pathogenicity and to allow for selection. To identify the genome as synthetic, we inserted "watermarks" at intergenic sites known to tolerate transposon insertions. Overlapping "cassettes" of 5 to 7 kilobases (kb), assembled from chemically synthesized oligonucleotides, were joined by in vitro recombination to produce intermediate (...) assemblies of approximately 24 kb, 72 kb ("1/8 genome"), and 144 kb ("1/4 genome"), which were all cloned as bacterial artificial chromosomes in Escherichia coli. Most of these intermediate clones were sequenced, and clones of all four 1/4 genomes with the correct sequence were identified. The complete synthetic genome was assembled by transformation-associated recombination cloning in the yeast Saccharomyces cerevisiae, then isolated and sequenced. A clone with the correct sequence was identified. The methods described here will be generally useful for constructing large DNA molecules from chemically synthesized pieces and also from combinations of natural and synthetic DNA segments. 10.1126/science.1151721. (shrink)

Analyzing the rate at which languages change can clarify whether similarities across languages are solely the result of cognitive biases or might be partially due to descent from a common ancestor. To demonstrate this approach, we use a simple model of language evolution to mathematically determine how long it should take for the distribution over languages to lose the influence of a common ancestor and converge to a form that is determined by constraints on language learning. We show that modeling (...) language learning as Bayesian inference of n binary parameters or the ordering of n constraints results in convergence in a number of generations that is on the order of n log n. We relax some of the simplifying assumptions of this model to explore how different assumptions about language evolution affect predictions about the time to convergence; in general, convergence time increases as the model becomes more realistic. This allows us to characterize the assumptions about language learning (given the models that we consider) that are sufficient for convergence to have taken place on a timescale that is consistent with the origin of human languages. These results clearly identify the consequences of a set of simple models of language evolution and show how analysis of convergence rates provides a tool that can be used to explore questions about the relationship between accounts of language learning and the origins of similarities across languages. (shrink)