This article addresses the physical chemical processes underlying biological self-organisation by which a homogenous solution of reacting chemicals spontaneously self-organises. Theoreticians have predicted that self-organisation can arise from a coupling of reactive processes with molecular diffusion. In addition, the presence of an external field, such as gravity, at a critical moment early in the process may determine the morphology that subsequently develops. The formation, in-vitro, of microtubules, a constituent of the cellular skeleton, shows this type of behaviour. The preparations spontaneously (...) self-organise by reaction-diffusion and the morphology that develops depends upon the presence of gravity at a critical bifurcation time early in the process. Here, we present numerical simulations of a population of microtubules that reproduce this behaviour. Microtubules can grow from one end whilst shrinking from the other. The shrinking end leaves behind a chemical trail of high tubulin concentration. Neighbouring microtubules preferentially grow into these regions, whilst avoiding regions of low tubulin concentration. The chemical trails produced by individual microtubules thus activate and inhibit the formation of neighbouring microtubules and this progressively leads to self-organisation. Gravity acts by way of its directional interaction with the macroscopic density fluctuations present in the solution arising from microtubule disassembly. (shrink)

Microtubules, major elements of the cell skeleton are, most of the time, well organized in vivo, but they can also show self-organizing behaviors in time and/or space in purified solutions in vitro. Theoretical studies and models based on the concepts of collective dynamics in complex systems, reaction–diffusion processes and emergent phenomena were proposed to explain some of these behaviors. In the particular case of microtubule spatial self-organization, it has been advanced that microtubules could behave like ants, self-organizing by ‘talking to (...) each other’ by way of hypothetic concentrated chemical trails of tubulin that are expected to be released by their disassembling ends. Deterministic models based on this idea yielded indeed like-looking spatio-temporal self-organizing behaviors. Nevertheless the question remains of whether microscopic tubulin trails produced by individual or bundles of several microtubules are intense enough to allow microtubule self-organization at a macroscopic level. In the present work, by simulating the diffusion of tubulin in microtubule solutions at the microscopic scale, we measure the shape and intensity of tubulin trails and discuss about the assumption of microtubule self-organization due to the production of chemical trails by disassembling microtubules. We show that the tubulin trails produced by individual microtubules or small microtubule arrays are very weak and not elongated even at very high reactive rates. Although the variations of concentration due to such trails are not significant compared to natural fluctuations of the concentration of tubuline in the chemical environment, the study shows that heterogeneities of biochemical composition can form due to microtubule disassembly. They could become significant when produced by numerous microtubule ends located in the same place. Their possible formation could play a role in certain conditions of reaction. In particular, it gives a mesoscopic basis to explain the collective dynamics observed in excitable microtubule solutions showing the propagation of concentration waves of microtubules at the millimeter scale, although we doubt that individual microtubules or bundles can behave like molecular ants. (shrink)

The building of a global model of carcinogenesis is one of modern biology’s greatest challenges. The traditional somatic mutation theory is now supplemented by a new approach, called the Tissue Organization Field Theory. According to TOFT, the original source of cancer is loss of tissue organization rather than genetic mutations. In this paper, we study the argumentative strategy used by the advocates of TOFT to impose their view. In particular, we criticize their claim of incompatibility used to justify the necessity (...) to definitively reject SMT. First, we note that since it is difficult to build a non-ambiguous experimental demonstration of the superiority of TOFT, its partisans add epistemological and metaphysical arguments to the debate. This argumentative strategy allows them to defend the necessity of a paradigm shift, with TOFT superseding SMT. To do so, they introduce a notion of incompatibility, which they actually use as the Kuhnian notion of incommensurability. To justify this so-called incompatibility between the two theories of cancer, they move the debate to a metaphysical ground by assimilating the controversy to a fundamental opposition between reductionism and organicism. We show here that this argumentative strategy is specious, because it does not demonstrate clearly that TOFT is an organicist theory. Since it shares with SMT its vocabulary, its ontology and its methodology, it appears that a claim of incompatibility based on this metaphysical plan is not fully justified in the present state of the debate. We conclude that it is more cogent to argue that the two theories are compatible, both biologically and metaphysically. We propose to consider that TOFT and SMT describe two distinct and compatible causal pathways to carcinogenesis. This view is coherent with the existence of integrative approaches, and suggests that they have a higher epistemic value than the two theories taken separately. (shrink)

This paper is devoted to computer modelling of the development and regeneration of multicellular biological structures. Some species are able to regenerate parts of their body after amputation damage, but the global rules governing cooperative cell behaviour during morphogenesis are not known. Here, we consider a simplified model organism, which consists of tissues formed around special cells that can be interpreted as stem cells. We assume that stem cells communicate with each other by a set of signals, and that the (...) values of these signals depend on the distance between cells. Thus the signal distribution characterizes location of stem cells. If the signal distribution is changed, then the difference between the initial and the current signal distribution affects the behaviour of stem cells—e.g. as a result of an amputation of a part of tissue the signal distribution changes which stimulates stem cells to migrate to new locations, appropriate for regeneration of the proper pattern. Moreover, as stem cells divide and form tissues around them, they control the form and the size of regenerating tissues. This two-level organization of the model organism, with global regulation of stem cells and local regulation of tissues, allows its reproducible development and regeneration. (shrink)

Large sets of elements interacting locally and producing specific architectures reliably form a category that transcends the usual dividing line between biological and engineered systems. We propose to call them morphogenetically architected complex systems. While taking the emergence of properties seriously, the notion of MACS enables at the same time the design of operational means that allow controlling and even, paradoxically, programming this emergence. To demonstrate our claim, we first show that among all the self-organized systems studied in the field (...) of Artificial Life, the specificity of MACS essentially lies in the close relation between their emergent properties and functional properties. Second, we argue that to be a MACS a system does not need to display more than weak emergent properties. Third, since the notion of weak emergence is based on the possibility of simulation, whether computational or mechanistic via machines, we see MACS as good candidates to help design artificial self-architected systems but also harness and redesign living ones. (shrink)

The genetic code has evolved from its initial non-degenerate wobble version until reaching its present state of degeneracy. By using the stereochemical hypothesis, we revisit the problem of codon assignations to the synonymy classes of amino-acids. We obtain these classes with a simple classifier based on physico-chemical properties of nucleic bases, like hydrophobicity and molecular weight. Then we propose simple RNA ring structures that present, overlap included, one and only one codon by synonymy class as solutions of a combinatory variational (...) problem. We compare these solutions to sequences of present RNAs considered as relics, with a high interspecific invariance, like invariant parts of tRNAs and micro-RNAs. We conclude by emphasizing some optimal properties of the genetic code. (shrink)

The field of synthetic biology is looking forward engineering framework for safely designing reliable de-novo biological functions. In this undertaking, Computer-Aided-Design environments should play a central role for facilitating the design. Although, CAD environment is widely used to engineer artificial systems the application in synthetic biology is still in its infancy. In this article we address the problem of the design of a high level language which at the core of CAD environment. More specifically the Gubs language is a specification (...) language used to describe the observations of the expected behaviour. The compiler appropriately selects components such that the observation of the synthetic biological function resulting to their assembly complies to the programmed behaviour. (shrink)

The classic model of blood pressure regulation by Guyton et al. set a new standard for quantitative exploration of physiological function and led to important new insights, some of which still remain the focus of debate, such as whether the kidney plays the primary role in the genesis of hypertension. Key to the success of this model was the fact that the authors made the computer code freely available and eventually provided a convivial user interface for exploration of model behavior (...) on early microcomputers. Ikeda et al. developed an offshoot of the Guyton model targeting especially the regulation of body fluids and acid–base balance; their model provides extended renal and respiratory functions and would be a good basis for further extensions. In the interest of providing a simple, useable version of Ikeda et al.’s model and to facilitate further such extensions, we present a practical implementation of the model of Ikeda et al., using the ODE solver Berkeley Madonna. (shrink)

Vision substitution by electro-stimulation has been studied since the 60s beginning with P. Bach-y-Rita. Camera pictures or movies encoded in gray levels are displayed using an electro-stimulation display device on the surface of a body part, such as the skin or the tongue. Medical-technical devices have been developed on this principle to compensate for sensory-motor disabilities such as blindness or loss of balance, or to guide specific actions, such as surgery. However, the electrical signals of stationary or moving slowly moving (...) objects, displayed on a Tongue display unit , are quickly lost due to saturation of receptors undergoing electrostimulation. We propose to add random saccades or sparkle to the displayed visual scene to increase the quality of pattern recognition by the subjects. In the present experimental trimodal study , we show that the presence of a moderate sparkle level enhances the perception of the direction of lines drawn on a TDU and reduces the response time. (shrink)

In this article we present a new kind of computing device that uses biochemical reactions networks as building blocks to implement logic gates. The architecture of a computing machine relies on these generic and composable building blocks, computation units, that can be used in multiple instances to perform complex boolean functions. Standard logical operations are implemented by biochemical networks, encapsulated and insulated within synthetic vesicles called protocells. These protocells are capable of exchanging energy and information with each other through transmembrane (...) electron transfer. In the paradigm of computation we propose, protoputing, a machine can solve only one problem and therefore has to be built specifically. Thus, the programming phase in the standard computing paradigm is represented in our approach by the set of assembly instructions that directs the wiring of the protocells that constitute the machine itself. To demonstrate the computing power of protocellular machines, we apply it to solve a NP-complete problem, known to be very demanding in computing power, the 3-SAT problem. We show how to program the assembly of a machine that can verify the satisfiability of a given boolean formula. Then we show how to use the massive parallelism of these machines to verify in less than 20 min all the valuations of the input variables and output a fluorescent signal when the formula is satisfiable or no signal at all otherwise. (shrink)

The Enzymatic control reactions model was presented within the scope of fractional calculus. In order to accommodate the usual initial conditions, the fractional derivative used is in Caputo sense. The methodologies of the three analytical methods were used to derive approximate solution of the fractional nonlinear system of differential equations. Two methods use integral operator and the other one uses just an integral. Numerical results obtained exhibit biological behavior of real world problem.

Building a meaningful model of biological regulatory network is usually done by specifying the components and their interactions, by guessing the values of parameters, by comparing the predicted behaviors to the observed ones, and by modifying in a trial-error process both architecture and parameters in order to reach an optimal fitness. We propose here a different approach to construct and analyze biological models avoiding the trial-error part, where structure and dynamics are represented as formal constraints. We apply the method to (...) Hopfield-like networks, a formalism often used in both neural and regulatory networks modeling. The aim is to characterize automatically the set of all models consistent with all the available knowledge. The available knowledge is formalized into formal constraints. The latter are compiled into Boolean formula in conjunctive normal form and then submitted to a Boolean satisfiability solver. This approach allows to formulate a wide range of queries, expressed in a high level language, and possibly integrating formalized intuitions. In order to explore its potential, we use it to find cycles for 3-nodes networks and to determine the flower morphogenesis regulatory network of Arabidopsis thaliana. Applications of this technique are numerous and concern the building of models from data as well as the design of biological networks possessing specified behaviors. (shrink)

Various threshold Boolean networks, a formalism used to model different types of biological networks, can produce similar dynamics, i.e. share same behaviors. Among them, some are complex, others not. By computing both structural and behavioral complexities, we show that most TBNs are structurally complex, even those having simple behaviors. For this purpose, we developed a new method to compute the structural complexity of a TBN based on estimates of the sizes of equivalence classes of the threshold Boolean functions composing the (...) TBN. (shrink)

The empirical study of belief is emerging at a rapid clip, uniting work from all corners of cognitive science. Reliance on belief in understanding and predicting behavior is widespread. Examples can be found, inter alia, in the placebo, attribution theory, theory of mind, and comparative psychological literatures. Research on belief also provides evidence for robust generalizations, including about how we fix, store, and change our beliefs. Evidence supports the existence of a Spinozan system of belief fixation: one that is automatic (...) and independent of belief rejection. Independent research supports the existence of a system of fragmented belief storage: one that relies on large numbers of causally isolated, context-sensitive stores of belief in memory. Finally, empirical and observational data support at least two systems of belief change. One system adheres, mostly, to epistemological norms of updating; the other, the psychological immune system, functions to guard our most centrally held beliefs from potential inconsistency with newly formed beliefs. Refining our under- standing of these systems can shed light on pressing real-world issues, such as how fake news, propaganda, and brainwashing exploit our psychology of belief, and how best to construct our modern informational world. (shrink)

This paper argues that contemporary philosophical literature on meaning in life has important implications for the debate about our obligations to non-human animals. If animal lives can be meaningful, then practices including factory farming and animal research might be morally worse than ethicists have thought. We argue for two theses about meaning in life: that the best account of meaningful lives must take intentional action to be necessary for meaning—an individual’s life has meaning if and only if the individual acts (...) intentionally in ways that contribute to finally valuable states of affairs; and that this first thesis does not entail that only human lives are meaningful. Because non-human animals can be intentional agents of a certain sort, our account yields the verdict that many animals’ lives can be meaningful. We conclude by considering the moral implications of these theses for common practices involving animals. (shrink)

Most physics theories are deterministic, with the notable exception of quantum mechanics which, however, comes plagued by the so-called measurement problem. This state of affairs might well be due to the inability of standard mathematics to “speak” of indeterminism, its inability to present us a worldview in which new information is created as time passes. In such a case, scientific determinism would only be an illusion due to the timeless mathematical language scientists use. To investigate this possibility it is necessary (...) to develop an alternative mathematical language that is both powerful enough to allow scientists to compute predictions and compatible with indeterminism and the passage of time. We suggest that intuitionistic mathematics provides such a language and we illustrate it in simple terms. (shrink)

Malebranche's Dialogues on Metaphysics and on Religion is in many ways the best introduction to his thought, and provides the most systematic exposition of his philosophy as a whole. In it, he presents clear and comprehensive statements of his two best-known contributions to metaphysics and epistemology, namely, the doctrines of occasionalism and vision in God; he also states his views on such central issues as self-knowledge, the existence of the external world and the problem of theodicy. His skilful handling of (...) the dialogue form enables the reader to see how he responds to objections made to his earlier work The Search after Truth. This edition presents a translation of the text which is clear, readable and more accurate than any of its predecessors, together with an introduction that analyses Malebranche's central teachings and explains the importance of the Dialogues in the context of seventeenth-century philosophy. (shrink)

It is usual to identify initial conditions of classical dynamical systems with mathematical real numbers. However, almost all real numbers contain an infinite amount of information. I argue that a finite volume of space can’t contain more than a finite amount of information, hence that the mathematical real numbers are not physically relevant. Moreover, a better terminology for the so-called real numbers is “random numbers”, as their series of bits are truly random. I propose an alternative classical mechanics, which is (...) empirically equivalent to classical mechanics, but uses only finite-information numbers. This alternative classical mechanics is non-deterministic, despite the use of deterministic equations, in a way similar to quantum theory. Interestingly, both alternative classical mechanics and quantum theories can be supplemented by additional variables in such a way that the supplemented theory is deterministic. Most physicists straightforwardly supplement classical theory with real numbers to which they attribute physical existence, while most physicists reject Bohmian mechanics as supplemented quantum theory, arguing that Bohmian positions have no physical reality. (shrink)

Do scientific theories limit human knowledge? In other words, are there physical variables hidden by essence forever? We argue for negative answers and illustrate our point on chaotic classical dynamical systems. We emphasize parallels with quantum theory and conclude that the common real numbers are, de facto, the hidden variables of classical physics. Consequently, real numbers should not be considered as ``physically real" and classical mechanics, like quantum physics, is indeterministic.

It is usual to identify initial conditions of classical dynamical systems with mathematical real numbers. However, almost all real numbers contain an infinite amount of information. I argue that a finite volume of space can’t contain more than a finite amount of information, hence that the mathematical real numbers are not physically relevant. Moreover, a better terminology for the so-called real numbers is “random numbers”, as their series of bits are truly random. I propose an alternative classical mechanics, which is (...) empirically equivalent to classical mechanics, but uses only finite-information numbers. This alternative classical mechanics is non-deterministic, despite the use of deterministic equations, in a way similar to quantum theory. Interestingly, both alternative classical mechanics and quantum theories can be supplemented by additional variables in such a way that the supplemented theory is deterministic. Most physicists straightforwardly supplement classical theory with real numbers to which they attribute physical existence, while most physicists reject Bohmian mechanics as supplemented quantum theory, arguing that Bohmian positions have no physical reality. (shrink)

Syllogisms (e.g. “All A are B; All B are C; What is true about A and C?”) are a long‐studied area of human reasoning. Riesterer, Brand, and Ragni compare a variety of models to human performance and show that not only do current models have a lot of room for improvement, but more importantly a large part of this improvement must come from examining individual differences in performance.

This article defends a relational account of personhood. I argue that the structure of personhood consists of dyadic relations between persons who can wrong or be wronged by one another, even if some of them lack moral competence. I draw on recent work on directed duties to outline the structure of moral communities of persons. The upshot is that we can construct an inclusive theory of personhood that can accommodate nonhuman persons based on shared community membership. I argue that, once (...) we unpack the internal relation between directed duties, moral status, and flourishing, relations can ground personhood and include nonhuman animals. (shrink)

We aim to do two things in this article. On the positive end, our goal is to explain how some seemingly incompatible aspects of belief live together, by presenting distinct mechanistic explanations of each of them: in particular we want to show how belief can be discerning, credulous, rational, and irrational. After clarifying our positive view, we take aim at some competitor views in the second half of the paper, particularly offering critiques of epistemic vigilance and social marketplace accounts of (...) belief. We conclude by inviting proponents to provide an architecture for belief that can be tested against existing models. (shrink)

This book is the first extensive treatment of Husserl's phenomenology of time-consciousness. Nicolas de Warren uses detailed analysis of texts by Husserl, some only recently published in German, to examine Husserl's treatment of time-consciousness and its significance for his conception of subjectivity. He traces the development of Husserl's thinking on the problem of time from Franz Brentano's descriptive psychology, and situates it in the framework of his transcendental project as a whole. Particular discussions include the significance of time-consciousness for (...) other phenomenological themes: perceptual experience, the imagination, remembrance, self-consciousness, embodiment, and the consciousness of others. The result is an illuminating exploration of how and why Husserl considered the question of time-consciousness to be the most difficult, yet also the most central, of all the challenges facing his unique philosophical enterprise"--Provided by publisher. (shrink)

The claim that the observation of a violation of a Bell inequality leads to an alleged alternative between nonlocality and non-realism is annoying because of the vagueness of the second term.

A growing literature argues that animals can act for moral reasons without being responsible. I argue that the literature often fails to maintain a clear distinction between moral behavior and moral agency, and I formulate a dilemma: either animals are less moral or they are more responsible than the literature suggests. If animals can respond to moral reasons, they are responsible according to an influential view of moral responsibility–Quality of Will. But if they are responsible, as some argue, costly implications (...) must be acknowledged. If, however, they should not be considered responsible, then we may have to reassess the meaning of animal morality. I discuss ways to eschew responsibility or to tailor it to animals and argue that each requires a revised conception of animal morality. (shrink)

Is suffering really bad? The late Derek Parfit argued that we all have reasons to want to avoid future agony and that suffering is in itself bad both for the one who suffers and impersonally. Nietzsche denied that suffering was intrinsically bad and that its value could even be impersonal. This paper has two aims. It argues against what I call ‘Realism about the Value of Suffering’ by drawing from a broadly Nietzschean debunking of our evaluative attitudes, showing that a (...) recently influential response to the debunking challenge (the appeal to phenomenal introspection) fails. It also argues that a Nietzschean approach is well suited to support the challenge and is bolstered by the empirical literature. As strangers to ourselves, we cannot know whether suffering is really intrinsically bad for us. (shrink)

My aim in this paper is to show that and how animal organisms are appropriate subjects of normative evaluation, on Hegel's view. I contrast my reading with the interpretive positions of Sebastian Rand and Mark Alznauer. I disagree with Rand and agree with Alznauer that animal organisms are normatively evaluable for Hegel. I substantiate my disagreement with Rand, and supplement Alznauer's interpretation, by spelling out the role that the ‘generic process’ or ‘genus process [Gattungsprozess]’ plays within Hegel's account of animal (...) organisms and their normative evaluability. In the course of my discussion, I highlight the main differences that Hegel purports to identify between animal and vegetable organisms and suggest that the upshot of those differences is that some but not all plants are normatively evaluable, by his lights. I also situate Hegel's discussion of theGattungsprozesswithin the debate on biological functions in the philosophy of biology over the last few decades. (shrink)

Discussions on indeterminism in physics focus on the possibility of an open future, i.e. the possibility of having potential alternative future events, the realisation of one of which is not fully determined by the present state of affairs. Yet, can indeterminism affect also the past, making it open as well? We show that by upholding principles of finiteness of information one can entail such a possibility. We provide a toy model that shows how the past could be fundamentally indeterminate, while (...) also explaining the intuitive (and observed) asymmetry between the past—which can be remembered, at least partially—and the future—which is impossible to fully predict. (shrink)

This longitudinal study investigated the capability of various positive psychological resources to directly or indirectly protect specific well-being outcomes and moderate the effects on well-being of health and economic threats in a lockdown situation during the 2020 health crisis in France. At the beginning of lockdown, participants completed self-assessment questionnaires to document their initial level of well-being and state of nine different well-established psychological resources, measured as traits: optimism, hope, self-efficacy, gratitude toward the world, self-transcendence, wisdom, gratitude of being, peaceful (...) disengagement, and acceptance. Three weeks later, a weekly follow-up was started to record changes in well-being and reported threats for a duration of 5 weeks. Results show that psychological resources efficiently protected well-being in a variety of ways: they buffered the adverse effects of reported threats to health and wealth, increased the well-being averages, and reduced the decline in well-being over time. More specifically, emotional well-being was positively predicted by hope, gratitude of being, and, to a lesser level, by acceptance; psychological well-being by self-efficacy, personal wisdom, and gratitude of being; social well-being only by gratitude toward the world; and inner well-being by optimism, gratitude of being, and acceptance. The study emphasizes the importance of cultivating psychological resources in ordinary times to protect individuals' well-being when difficult and extraordinary circumstances occur. It also offers clues to the kind of resources one may want to develop. (shrink)

Animals who live in cities must coexist with us. They are, as a result, entitled to the conditions of their flourishing. This article argues that, as the boundaries of cities and urban areas expand, the boundaries of our conception of captivity should expand too. Urbanization can undermine animals’ freedoms, hence their ability to live good lives. I draw the implications of an account of “pervasive captivity” against the background of the Capabilities Approach. I construe captivity, including that of urban animals, (...) as affecting a range of animal capabilities, understood as freedoms, and I address some tensions within Nussbaum’s treatment of human-animal conflicts. Using the Capabilities Approach as a guide, I will attempt to motivate a convergence between habitat preservation in urbanized environments, urban design guided by justice, and the individual freedoms of animals. (shrink)

Sometimes physicians lie to third-party payers in order to grant their patients treatment they would otherwise not receive. This strategy, commonly known as gaming the system, is generally condemned for three reasons. First, it may hurt the patient for the sake of whom gaming was intended. Second, it may hurt other patients. Third, it offends contractual and distributive justice. Hence, gaming is considered to be immoral behavior. This article is an attempt to show that, on the contrary, gaming may sometimes (...) be a physician's duty. Under specific circumstances, gaming may be necessary from the viewpoint of the internal morality of medicine. Moreover, the objections against gaming are examples of what we call the idealistic fallacy, that is, the fallacy of passing judgments in a nonideal world according to ideal standards. Hence, the objections are inconclusive. Gaming is sometimes justified, and may even be required in the name of beneficence. (shrink)

The following paper argues that issues in paradigmatic proposals for solving the new demarcation problem stem from absolutist assumptions about judgments of value legitimacy. Both the problem of uninformativeness (Larroulet Philippi 2020; Fernandez-Pinto 2014, 2015) and the problem of ambiguous judgments of cases (Hicks 2014; Intemann 2017) are explained by an absolutist pretension contained in one of the main aims of these proposals: providing criteria for differentiating legitimate from illegitimate uses of values, without qualification. After presenting the problems and showing (...) how they stem from that common source, we will sketch a way forward, inspired mainly by Joseph Rouse’s Beyond Epistemic Sovereignty (1996), advancing routes that can allow philosophers of science to evade these pitfalls and engage with scientific practice in a more salutary manner. (shrink)

Recent models of the conceptual system hold that concepts are grounded in simulations of actual experiences with instances of those concepts in sensory-motor systems (e.g., Barsalou, 1999, 2003; Solomon & Barsalou, 2001). Studies supportive of such a viewhave shown that verifying a property of a concept in one modality, and then switching to verify a property of a different concept in a different modality generates temporal processing costs similar to the cost of switching modalities in perception. In addition to non-emotional (...) concepts, the present experiment investigated switching costs in verifying properties of positive and negative (emotional) concepts. Properties of emotional concepts were taken from vision, audition, and the affective system. Parallel to switching costs in neutral concepts, the study showed that for positive and negative concepts, verifying properties from different modalities produced processing costs such that reaction times were longer and error rates were higher. Importantly, this effect was observed when switching from the affective system to sensory modalities, and vice-versa. These results support the embodied cognition view of emotion in humans. (shrink)

Based on anthropological fieldwork on the revival of hallucinogen research as well as on the epistemic culture of neurophilosophy, this Common Knowledge guest column examines two very different philosophical engagements with psychedelic drugs. In Thomas Metzinger's evidence-based philosophy of mind, hallucinogens help to operationalize questions about the nature of consciousness. While this project contributes to the great divide between empirically enlightened moderns and tradition-oriented premoderns, Metzinger's neurophilosophical reanimation of the ancient conception of philosophy as cultura animi can build a bridge (...) to Aldous Huxley's perennial philosophy, which has informed the psychedelic intelligentsia like no other body of thought. In the sixteenth century, the philosophia perennis grew out of a decidedly nonmodern philosophy of religion that sought to suture the historical and cultural cracks that would come to define modernity. This essay argues that neurophilosophy and ethnographic studies of consciousness cultures could function as critical correctives in a contemporary rearticulation of perennial philosophy. (shrink)

Recent models of the conceptual system hold that concepts are grounded in simulations of actual experiences with instances of those concepts in sensory-motor systems (e.g., Barsalou, 1999, 2003; Solomon & Barsalou, 2001). Studies supportive of such a viewhave shown that verifying a property of a concept in one modality, and then switching to verify a property of a different concept in a different modality generates temporal processing costs similar to the cost of switching modalities in perception. In addition to non-emotional (...) concepts, the present experiment investigated switching costs in verifying properties of positive and negative (emotional) concepts. Properties of emotional concepts were taken from vision, audition, and the affective system. Parallel to switching costs in neutral concepts, the study showed that for positive and negative concepts, verifying properties from different modalities produced processing costs such that reaction times were longer and error rates were higher. Importantly, this effect was observed when switching from the affective system to sensory modalities, and vice-versa. These results support the embodied cognition view of emotion in humans. (shrink)

The causal view of categories assumes that categories are represented by features and their causal relations. To study the effect of causal knowledge on categorization, researchers have used Bayesian causal models. Within that framework, categorization may be viewed as dependent on a likelihood computation (i.e., the likelihood of an exemplar with a certain combination of features, given the category's causal model) or as a posterior computation (i.e., the probability that the exemplar belongs to the category, given its features). Across three (...) experiments, in combination with computational modeling, we offer evidence that categorization is better accounted for by assuming that people compute posteriors and not likelihoods, though both probabilities are closely related. This result contrasts with existing analyses of causal-based categorization, which assume that likelihood computations give a good approximation of human judgments. We also find that people are able to compute likelihoods in a closely related task that elicits judgments of consistency rather than category membership judgments. Our analyses show that people do use causal probabilistic information as prescribed by a Bayesian model but that they flexibly compute likelihoods or posteriors depending on the task. We discuss our results in relation to the relevant literature on the topic. (shrink)

L’auteur souhaite s’extraire du piège consistant à s’enferrer dans le débat sur le maintien de l’ordre pour se pencher sur les raisons profondes qui sous-tendent la répression brutale contre les Soulèvements de la Terre. Pour lui, il s’agit de réprimer la remise en cause du système sur le plan de la production (et non plus sur celui de la consommation) par la défense des territoires. Ceci traduit l’affrontement de deux mondes, la remise en cause du rapport entre humain·es et autres (...) qu’humain·es. (shrink)

The idea that appearances provide justifications for beliefs—the principle of phenomenal conservatism—is self-evidently true. In the case of cognitive penetration, however, it seems that certain irrational etiologies of a belief may influence the epistemic quality of that belief. Susanna Siegel argues that these etiologies lead to ‘epistemic downgrade.’ Instead of providing us with a decisive objection, cognitive penetration calls for us to clarify our epistemic framework by understanding the formative parts of appearances. In doing so, the two different but inseparable (...) ideas of sensation and intellection provide us with a basis of our appearances. These appearances, in turn, provide us with the objective evidence needed to test our judgements. Thus, the extra-sensory concepts of intellectual identification and the appearances they help form become an epistemic groundwork. (shrink)