We present a general framework for analyzing the contribution to reproductive success of a behavioural action. An action may make a direct contribution to reproductive success, but even in the absence of a direct contribution it may make an indirect contribution by changing the animal's state. We consider actions over a period of time, and define a reward function that characterizes the relationship between the animal's state at the end of the period and its future reproductive success. Working back from (...) the end of the period using dynamic programming, the optimal action as a function of state and time can be found. The procedure also yields a measure of the cost, in terms of future reproductive success, of a suboptimal action. These costs provide us with a common currency for comparing activities such as eating and drinking, or eating and hiding from predators. The costs also give an indication of the robustness of the conclusions that can be drawn from a model. We review how our framework can be used to analyze optimal foraging decisions in a stochastic environment. We also discuss the modelling of optimal daily routines and provide an illustration based on singing to attract a mate. We use the model to investigate the features that can produce a dawn song burst in birds. State is defined very broadly so that it includes the information an animal has about its environment. Thus, exploration and learning can be included within the framework. (shrink)

A general framework for analysing the effects of variability and the effects of interruptions on foraging is presented. The animal is characterised by its level of energetic reserves, x. We consider behaviour over a period of time [0,T]. A terminal reward function R(x) determines the expected future reproductive success of an animal with reserves x at time T. For any state x at a time in the period, we give the animal a choice between various options and then constrain it (...) to follow a background strategy. The best option is the one that maximizes expected future reproductive success. Using this framework, we show that sensitivity to variability in amount of energy gained is logically distinct from sensitivity to variability in the time at which food is obtained. We also show that incorporating interruptions results in both a preference for variability in time and a preference for a reward followed by a delay as opposed to the same delay before the reward. (shrink)

Gould and Lewontin use San Marco, Venice, to criticise the adaptationist program in biology. Following their lead, the architectural term “spandrel” is now widely used in biology to denote a feature that is a necessary byproduct of other aspects of the organism. I review the debate over San Marco and argue that the spandrels are not necessary in the sense originally used by Gould and Lewontin. I conclude that almost all the claims that Gould makes about San Marco are wrong (...) and that it is reasonable to view the architectural spandrel as an adaptation. The spandrels example has not provided a good illustration of why adaptive explanations should be avoided. In fact, it can be used as an example of how adaptive explanations can be dismissed even when there is evidence in their favour. I also discuss the use of the concept of a spandrel in biology. (shrink)

I discuss various theoretical issues concerning maximizing, matching, and melioration. The model of addiction based on melioration has the key feature that a reduction in drag use increases both the value of drag-taking and the value of conventional activities. I found Heyman's target article stimulating. I don't feel competent to comment on drags but I do have some thoughts, both general and specific, on the theoretical issues.

Gigerenzer, Todd, and the ABC Research Group give an interesting account of simple decision rules in a variety of contexts. I agree with their basic idea that animals use simple rules. In my commentary I concentrate on some aspects of their treatment of decision rules in behavioural ecology.

Rolls discusses various adaptive explanations of physiological processes and the emotions. We give a critical analysis of some of these from the perspective of behavioural ecology. While agreeing with the approach adopted by Rolls, we identify topics that could have been better presented by making use of the existing literature.

We concentrate on two aspects of the article by Pothos & Busemeyer (P&B): the relationship between classical and quantum probability and quantum probability as a basis for rational decisions. We argue that the mathematical relationship between classical and quantum probability is not quite what the authors claim. Furthermore, it might be premature to regard quantum probability as the best practical rational scheme for decision making.

John Maynard Smith was the founder of evolutionary game theory. He has also been the major influence on the direction of this field, which now pervades behavioural ecology and evolutionary biology. In its original formulation the theory had three components: a set of strategies, a payoff structure, and a concept of evolutionary stability. These three key components are still the basis of the theory, but what is assumed about each component is often different to the original assumptions. We review modern (...) approaches to these components. We emphasis that if a game is considered in isolation, and arbitrary payoffs are assumed, then the payoffs may not be consistent with other components of the system which are not modelled. Modelling the whole system, including not only the focal game, but also the future behaviour of the players and the behaviour of other population members, allows a consistent model to be constructed. We illustrate this in the case of two models of parental care, showing how linking a focal game to other aspects of the system alters what is predicted. (shrink)

In the theory outlined in the target article, an animal forages continuously, making sequential decisions in a world where the amount of food and its uncertainty are fixed, but delays are variable. These assumptions contrast with the risk-sensitive foraging theory and create a problem for comparing the predictions of this model with many laboratory experiments that do not make these assumptions.

It is shown that in a range of models, the probability that a forager dies from starvation is, to a good approximation, an exponential function of energy reserves. Using a time and energy budget for a 19g passerine, we explore the consequences, in terms of starvation and predation, of various levels of energy reserves. It is shown that there exists an optimal level L of reserves at which total mortality (starvation plus predation) is minimized. L increases when the environment deteriorates (...) as a result of a decrease in either temperature or mean gross gain or an increase in the mean search time. The effect of combined deteriorations is greater than the sum of their individual effects. At L, the probability of predation is much higher than the probability of starvation. A simple analytic model suggests that this result will be fairly general, but also indicates conditions under which the result might not hold. (shrink)

Hebbian mechanisms are justified according to their functional utility in an evolutionary sense. The selective advantage of correlating content-contingent stimuli reflects the putative common cause of temporally or spatially contiguous inputs. The selective consequences of such correlations are discussed by using examples from the evolution of signal form in sexual selection and model-mimic coevolution. We suggest that evolutionary justification might be considered in addition to neurophysiology plansibility when constructing representational models.

Behavioral ecologists often assume that natural selection will produce organisms that make optimal decisions. In the context of information processing, this means that the behavior of animals will be consistent with models from fields such as signal detection theory and Bayesian decision theory. We discuss work that applies such models to animal behavior and use the case of Bayesian updating to make the distinction between a description of behavior at the level of optimal decisions and a mechanistic account of how (...) decisions are made. The idea of ecological rationality is that natural selection shapes an animal's decision mechanisms to suit its environment. As a result, decision-making mechanisms may not perform well outside the context in which they evolved. Although the assumption of ecological rationality is plausible, we argue that the exact nature of the relationship between ecology and cognitive mechanism may not be obvious. (shrink)

Gangestad & Simpson review sexual selection theory and discuss their work on fluctuating asymmetry and mate preference in humans. We question some aspects of their account and mention problems with the data. We also suggest that more theoretical work on complex but realistic mating systems is required.

We present a dynamic programming model which is used to investigate hypothermia as an adaptive response by small passerine birds in winter. The model predicts that there is a threshold function of reserves during the night, below which it is optimal to enter hypothermia, and above which it is optimal to rest. This threshold function decreases during the night, with a particularly sharp drop at the end of the night, representing the time and energy costs associated with returning to normal (...) body temperature. The results of the model emphasise the trade-off between energy and predation, not just between foraging options, but also between foraging during the day and entering hypothermia at night. The value of being able to use hypothermia represents not just energy savings, but also reduced predation risk due to changes in the optimal foraging strategy. Conditions which give a high value of hypothermia are short photoperiod, variable food supply, low temperatures, poor and scarce food supplies. (shrink)

ABSTRACTThis paper relates Kant’s account of pure apperception to the agential approach to self-knowledge. It argues that his famous claim ‘The I think must be able to accompany all of my represent...

Deep brain stimulation of the subthalamic nucleus is a clinically effective tool for treating medically refractory Parkinson’s disease, but its neural mechanisms remain debated. Previous work has demonstrated that STN DBS results in evoked potentials in the primary motor cortex, suggesting that modulation of cortical physiology may be involved in its therapeutic effects. Due to technical challenges presented by high-amplitude DBS artifacts, these EPs are often measured in response to low-frequency stimulation, which is generally ineffective at PD symptom management. This (...) study aims to characterize STN-to-cortex EPs seen during clinically relevant high-frequency STN DBS for PD. Intraoperatively, we applied STN DBS to 6 PD patients while recording electrocorticography from an electrode strip over the ipsilateral central sulcus. Using recently published techniques, we removed large stimulation artifacts to enable quantification of STN-to-cortex EPs. Two cortical EPs were observed – one synchronized with DBS onset and persisting during ongoing stimulation, and one immediately following DBS offset, here termed the “start” and the “end” EPs respectively. The start EP is, to our knowledge, the first long-latency cortical EP reported during ongoing high-frequency DBS. The start and end EPs differ in magnitude and latency, and the end, but not the start, EP magnitude has a significant relationship to ongoing high gamma power during the EP. These contrasts may suggest mechanistic or circuit differences in EP production during the two time periods. This represents a potential framework for relating DBS clinical efficacy to the effects of a variety of stimulation parameters on EPs. (shrink)

There are two prevailing interpretations of the status which Kant accorded his claims in the Critique of Pure Reason: 1) he is analyzing our concepts of cognition and experience; 2) he is making empirical claims about our cognitive faculties. I argue for a third alternative: on Kant's account, all cognition consists in a reflective consciousness of our cognitive faculties, and in critique we analyze the content of this consciousness. Since Strawson raises a famous charge of incoherence against such a position, (...) I begin by showing that this charge is misplaced. (shrink)

What makes a subject''s motivationrational is its originating in her practicalreasoning. I explain the appeal of this thesisabout rational motivation, and explore itsrelation to recent discussions of internalismabout reasons for action. I do so in theservice of clarifying an important meta-ethicaldebate between Humean motivational skeptics andtheir Kantian opponents. This debate is oneover whether, as this skeptic contends andKantians deny, considerations about ourmotivational capacities, together withinternalism, restrict genuine reasons foraction to merely instrumental ones. I arguethat properly adjudicating this debate requiresidentifying one (...) particular way in which thethesis about rational motivation has beendeveloped – namely, as a part of what I term``the traditional conception'''' of themotivational efficacy of practical reason. Onthis conception, rational motivation consistsin choosing some course of conduct out of one''scognitive appreciation of the way its relationto one''s practicable good gives one reason todo so. And I side with Kantians against theHumean motivational skeptic in part on groundsthat Kant himself – though not all Kantians –would find congenial: namely, that we shouldaccept the traditional conception. (shrink)

In what follows, I argue that Hume works with a notion of the a priori that, though unfamiliar today, was standard in the seventeenth and eighteenth centuries. On this notion of the a priori, to know (consider, prove) something a priori is to know (consider, prove) it from the grounds that make it true. I will refer to this as the "from-grounds" notion of the a priori, and to the now-familiar and dominant notion—on which to know something a priori is (...) to know it with a justification that is independent of experience—as the "non-empirical" notion.Hume holds, as a substantive thesis, that one knows something a priori, where 'a priori' is understood in the from-grounds sense, only if one knows it independently of .. (shrink)

According to St. Thomas, the natures of material things are the proper objects of human understanding.Thomas claims only that the natures of things are the proper objects of the intellect, not that they are its only objects: he does not deny that we have intellective cognition also of the contingent states and situations of particular material things. And he holds that, at least in this life, humans cognize these natures, not through innate species or by perceiving the divine exemplars, but (...) only by abstraction from phantasms (ST Ia, 84.7, 85.1).This claim applies to the exercising of concepts already acquired, as well as their initial acquisition (ST Ia 84.7). Here and throughout, I use “cognition” to translate “cognitio.” As Scott MacDonald (“Theory of Knowledge” in Cambridge Companion to Aquinas, ed., N. Kretzmann and E. Stump [Cambridge: Cambridge University Press, 1993], p. 162) points out, translating “cognitio” with “knowledge” is misleading, given that cognitiones can, on Thomas’s account, be false (see, for example, ST Ia 17.3). I discuss Aquinas’s conception of cognition in section I.1. More precisely, the human intellect’s active component, the agent intellect, produces cognition of the natures of material things by abstracting intelligible forms from phantasms and informing them on its passive component, the possible intellect, to actualize the latter’s potency to understand.This division of the intellect into an active and a passive component originates in Aristotle’s cryptic remark that in the soul “there is a mind for becoming all things” and “a mind for producing all things” (DA III 5, 430a10). This passage has been subject to myriad interpretations. Aristotle’s Arabic commentators read him as saying that (one or both) of these intellects are single and separate from individual human souls. In opposition to these interpretations, Aquinas holds that the agent and possible intellects are both immanent powers of each individual soul. Since these interpretations enjoyed considerable popularity in Aquinas’s day, we often find him developing his account of the human intellect in explicit opposition to them (cf. OUIAA). The aim of the present piece is to clarify Thomas’s account of this intellective abstraction, and thereby the precise force of the conceptual empiricism it asserts.Important recent work by several scholars has advanced our understanding of many central aspects of Aquinas’s philosophy of mind and epistemology, including his account of intellective abstraction. See Eleonore Stump, “Aquinas on the Foundations of Knowledge,” Canadian Journal of Philosophy (Supplementary Volume) 17 (1992); “Aquinas’s Account of the Mechanisms of Intellective Cognition,” Revenue Internationale de Philosophie 52 (1998): 287–307; “Aquinas on Sensory Cognition,” in Medieval Analyses in Language and Cognition, eds. Sten Ebbesen and Russell L. Friedman, volume 77 in the series Det Kongelige Danske Videnskabernes Selskab, Historisk-Filosofiske Meddelelser (Copenhagen: Munksgaard, 1999), pp. 377–395. Norman Kretzmann, “Infallibility, Error, and Ignorance,” Canadian Journal of Philosophy 17 (1992); Kretzmann, “Philosophy of Mind,” in Cambridge Companion to Aquinas; Robert Pasnau, Theories of Cognition in the Later Middle Ages (Cambridge: Cambridge University Press, 1997); and Scott MacDonald (“Theory of Knowledge,” in Cambridge Companion to Aquinas).Many of these discussions share a salutary focus on Aquinas’s claims regarding the reliability of our faculties, so that their treatments of intellective abstraction tend to center on his prima faciae wildly implausible claim to its infallibility: “The proper object of intellect is the quiddity of a thing, and this is why intellect is not fallible regarding the quiddity of a thing, speaking of it just as such” (ST Ia 85.6). Kretzmann provides an interesting and detailed treatment of this claim. Drawing on a range of texts, he argues that the intellect’s apprehension of the quiddity of a thing is such that one acquires an initial, crude concept of that thing, and that this apprehension must be distinguished from the intellect’s act of compounding, in judgments, the aspects of things so apprehended: it is only through a fallible, and extended process of making such judgments that we arrive at more adequate concepts of things (see the final section of “Infallibility, Error, and Ignorance”). MacDonald also makes insightful, and complementary, observations along similar lines (pp. 183–84). However, though helpful, these points do not suffice to explain, let alone render defensible, Thomas’s claim of infallibility: why can’t some of our acts of intellective abstraction yield false cognitions (however rudimentary), in the sense Thomas specifies?; in other words; why can’t the agent intellect sometimes produce in the possible intellect forms which do not correspond to the forms that actually inhere, or even could inhere, in material things? I think that Stump is right to take this optimism to be one striking instance of Thomas’s general epistemic optimism rooted in his conviction that God designed our cognitive faculties (Stump, “Foundations of Knowledge,” pp. 145–48).The interpretation of his intellective abstraction provided here complements Stump’s insight. For it, in effect, elaborates how Aquinas’s theistic metaphysics grounds his epistemic optimism about the first operation of our intellect. In particular, it explains how the agent intellect, as the human participating likeness in the divine light of understanding, has the active potency to order phantasms in such a way that it can produce in the possible intellect intelligible species which are determinate likenesses of the particular material things of which we have experience (cf. Section III iv, below). Examining his distinction between sensible and intellectual cognition, and his account of the way the former, in phantasms, supplies the data for intellective abstraction, will lead us to reassess the nature of Thomas’s antinativism—arguably the most important historical and philosophical legacy of his cognitive psychology. (shrink)

Kant's account of the way in which our faculty of discursive understanding acts on what is given in our sensible intuition to produce experience lies at the heart of his critical philosophy. The present study is devoted to explicating this account. Kant distinguishes the operation of discursive understanding in sensible intuition, its operation in the guise of the productive imagination, from its operation in forming clear concepts of the objects of the productive imagination. The former brings about the relations of (...) the contents of sensible intuition in space and time by representing these relations. The latter produces clear concepts in a process of comparison, abstraction, and reflection. ;In elaborating this account, I proceed first by examining Kant's contrast between intuition and concept, in order to clarify the contrast between cognition in intuition and cognition through clear concepts. I then examine Kant's reception and development of the Leibnizian account of the clarity and obscurity of representations. This examination in turn prepares the way for my reading of Kant's account of concept formation as an analytic process by which we produce the logical form of our concepts. All this serves to sharpen our understanding, not only of the relation between the two levels at which discursive understanding operates in bringing about experience, but also of Kant's central notions of consciousness and the form of cognition. Finally, I turn to examining Kant's account of the origin of the categories. I show that, on this account, the real sensible content of the categories--form of our cognition of objects--is represented obscurely in the synthesis of the productive imagination, and is brought to clarity in a process analogous to that whereby we acquire all our concepts by giving them their logical form. (shrink)

The central task to which contemporary moral philosophers have addressed themselves is that of listing the distinctive characteristics of moral utterances. In this paper I am concerned to propound an entirely negative thesis about these characteristics. It is widely held that it is of the essence of moral valuations that they are universalisable and prescriptive. This is the contention which I wish to deny. I shall proceed by first examining the thesis that moral judgments are necessarily and essentially universalisable and (...) then the thesis that their distinctive function is a prescriptive one. But as the argument proceeds I shall be unable to separate the discussion of the latter thesis from that of the former. (shrink)

‘Applied ethics’, as that expression is now used, is a single rubric for a large range of different theoretical and practical activities. Such rubrics function partly as a protective device both within the academic community and outside it; a name of this kind suggests not just a discipline, but a particular type of discipline. In the case of ‘applied ethics’ the suggestive power of the name derives from a particular conception of the relationship of ethics to what goes on under (...) the rubric of ‘applied ethics’. Not everyone who conducts activities under that rubric owes allegiance to this conception and there are doubtless some who would repudiate it as strongly as I do. But it is that dominant conception from which most work in this area derives or aspires to derive its philosophical legitimacy. What is that conception? (shrink)

"Every word, like a sacred object, has its place. No _précis_ is possible. This extraordinary book must be read."—Edmund Carpenter, _New York Times Book Review _ "No outline is possible; I can only say that reading this book is a most exciting intellectual exercise in which dialectic, wit, and imagination combine to stimulate and provoke at every page."—Edmund Leach, _Man _ "Lévi-Strauss's books are tough: very scholarly, very dense, very rapid in argument. But once you have mastered him, human history (...) can never be the same, nor indeed can one's view of contemporary society. And his latest book, _The Savage Mind_, is his most comprehensive and certainly his most profound. Everyone interested in the history of ideas _must_ read it; everyone interested in human institutions _should _read it."—J. H. Plumb, _Saturday Review_ "A constantly stimulating, informative and suggestive intellectual challenge."—Geoffrey Gorer, _The Observer_, London. (shrink)

In 1987, Roy Sorensen coined the term 'parahistory' to denote the study of genuinely anachronistic artefacts delivered by time travel.¹ 'Parahistory' would thus stand to history rather as parapsychology is claimed to stand to psychology, i.e. the parahistorian would study historical data that were obtained through channels that orthodox science does not recognise. How might one establish credentials as a time traveller? What sort of evidence could a time-traveller point to in support of claims that would presumably command a great (...) deal of scepticism? While successful predictions might be one confirmatory tool, supporting evidence needn't take the form of predictions. (Although Sorensen offers an intriguing argument that a Humean about miracle-testimony would be obliged to reject any testimony to the occurrence of time travel.) Perhaps artefacts that time travellers retrieve from other times (past or future) could usefully supplement testimonial or predictive evidence for the parahistorian. However, this paper will argue, any appeal to past-artefactual evidence for parahistorical claims faces a dilemma that threatens to undermine its value: appeals to past-artefact evidence must either collapse into appeals to predictive evidence or see their value diminished by such past artefacts' necessarily exhibiting contradictory indicators of age and period. (shrink)

Around 1998, internet postings began appearing under the alias ‘ Timetravel_0 ’. This alias was later replaced by ‘John Titor’, and it's as such I'll designate the posts' author. Remarkably, Titor claimed to have time-travelled from 2036 on a mission to retrieve an IBM 5100 in 1975. Titor refrained from public appearances and any evidence for his story remains web-bound but before closing shop c. March 24 th 2001, he described various future events, e.g.: Y2K is a disaster. Many people (...) die on the highways when they freeze to death trying to get to warmer weather. Cancellation of the Olympics after 2004 due to world conflict. America will soon be engaged in civil war with itself; a civil war that we'll see the beginnings of during 2004 and 2005, escalating until it is indisputable by 2008. This equivocal civil war fizzles until global nuclear war kills three billion people in 2015. (shrink)

One legacy of post-Enlightenment dualism in the universe of academic discourse is the presence of two approached to notions of duality championed by two differing camps. One camp might arbitrarily be called debunkers; the other might be labeled rationalists. The strategies of the camps are conditioned by traditional notions of inside and outside. Debunkers consider themselves outsiders, beyond a deceptive show filled with tricky mirrors. Rationalists, by contrast, spend a great deal of time among mirrors, listening to explanations from the (...) overseers, attempting to absorb sideshow language, hoping to provide acceptable analytical accounts. If debunkers are intent on discovering generative and, presumably, hidden ideological inscriptions of a given discourse—its situation on what Amiri Baraka calls the “real side” of economic exchange and world exploitative power—rationalists are concerned to study discursive products, to decode or explain them according to forms and formulas that claim to avoid general views or judgments of ideology. Differentiating the camps also is what might be called a thermal gradient: the heat of the debunker’s passion is palpable. It is unnecessary to command him, in the manner of the invisible man’s tormentor, to “Get hot, boy! Get hot!” Rationalists, by contrast, do not radiate. They appear to have nothing personal at stake and remain coolly instructive and intelligently unflappable in their analyses.This tale of an Enlightenment legacy, as I have told it, contrasts a debunking body and rationalist soul. As I have suggested in my opening sentence, however, what is at issue is not so much two actual and substantially distinctive camps as two metonyms for dual approaches to a common subject—namely, notions of duality. My claim is that the Enlightenment reflexivity of academic discourse, devoted to, say, “the Other” and conceived in dualistic terms of self-and-other, expresses itself as an opposition. Thos whom I have called debunkers gladly accept the Other’s sovereignty as a bodily and aboriginal donnée; rationalists work to discover the dynamics of “othering” engaged in by a self-indulgent Western soul. The difficulty of producing usefully analytical or political results for either camp is occasioned by their joint situation within a post-Enlightenment field. Houston A. Baker, Jr. is the Albert M. Greenfield Professor of Human Relations at the University of Pennsylvania. He is a poet whose recent volume Blues Journeys Home appeared in 1985. He is also the author of a number of studies of Afro-American literature and culture, including the forthcoming Modernism and the Harlem Renaissance. (shrink)

It is not wholly clear the extern to which Nel Nodding intends her ethic of caring to be an ethic that stands on its own in competition with others described by ethical theories. I argue that, given this ambiguity, Nodding' ethic of caring is a dangerous ethic because it can abet exploitation. I consider Noddings'responses to this criticism and conclude that the relational ontology of the ethic cannot rescue it from the charges of abetting exploitation.

Kathryn Morgan has introduced us to a typology of ‘the ways in which women’s moral voice and her sense of moral integrity are twisted and destroyed by patriarchal ideology and lived experience.’ She claims that this experience can induce in women ‘a sense of confusion and genuine moral madness.’I am in agreement with much of what Morgan says. However, I suspect that some others might find her case less convincing than I for the reason that she supports her claims by (...) an appeal to classical philosophical literature and what we might loosely call ‘sociological observations.’ One can imagine the easy retort—‘Yes, well, it’s true that Aristotle, Aquinas, Rousseau and Kant did say those silly things about women, but their remarks were mere asides and no one takes them seriously in this matter any more anyway. (shrink)

Kathryn Morgan has introduced us to a typology of ‘the ways in which women’s moral voice and her sense of moral integrity are twisted and destroyed by patriarchal ideology and lived experience.’ She claims that this experience can induce in women ‘a sense of confusion and genuine moral madness.’I am in agreement with much of what Morgan says. However, I suspect that some others might find her case less convincing than I for the reason that she supports her claims by (...) an appeal to classical philosophical literature and what we might loosely call ‘sociological observations.’ One can imagine the easy retort—‘Yes, well, it’s true that Aristotle, Aquinas, Rousseau and Kant did say those silly things about women, but their remarks were mere asides and no one takes them seriously in this matter any more anyway. (shrink)

Recent writers in feminist ethics have been concerned to find ways to reclaim and augment women's moral agency. This essay considers Sarah Hoagland's intriguing suggestion that we renounce moral praise and blame and pursue what she calls an "ethic of intelligibility." I argue that the eschewal of moral blame would not help but rather hinder our efforts to increase our sense of moral agency. It would, I claim, further intensify our demoralization.

I discuss a collection of problems in relevance logic. The main problems discussed are: the decidability of the positive semilattice system, decidability of the fragments of R in a restricted number of variables, and the complexity of the decision problem for the implicational fragment of R. Some related problems are discussed along the way.