The received view on the problem of the direction of time holds it that time has no intrinsic dynamical properties, and that its apparent asymmetry, to be understood in purely topological terms, is dependent on the directional properties of physical processes. In this paper we shall challenge both claims, in the light of an algebraic representation of time. First, we will show how to give a precise formulation to the intuitive idea that time possesses an intrinsic dynamics; this formulation (...) relies on the fact that the algebraic properties of time can equivalently be understood in dynamical terms. Second, we shall argue that the directional properties displayed by the processes occurring in time depend on the directional properties of time, rather than the converse. (shrink)

If one demystifies entropy the second law of thermodynamics comes out as an emergent property entirely based on the simple dynamic mechanical laws that govern the motion and energies of system parts on a micro-scale. The emergence of the second law is illustrated in this paper through the development of a new, very simple and highly efficient technique to compare time-averaged energies in isolated conservative linear large scale dynamical systems. Entropy is replaced by a notion that is much more transparent (...) and more or less dual called ectropy. Ectropy has been introduced before but we further modify the notion of ectropy such that the unit in which it is expressed becomes the unit of energy. The second law of thermodynamics in terms of ectropy states that ectropy decreases with time on a large enough time-scale and has an absolute minimum equal to zero. Zero ectropy corresponds to energy equipartition. Basically we show that by enlarging the dimension of an isolated conservative linear dynamical system and the dimension of the system parts over which we consider time-averaged energy partition, the tendency towards equipartition increases while equipartition is achieved in the limit. This illustrates that the second law is an emergent property of these systems. Finally from our large scale linear dynamic model we clarify Loschmidt’s paradox concerning the irreversible behavior of ectropy obtained from the reversible dynamic laws that govern motion and energy at the micro-scale. (shrink)

We investigated the possible causes of perceptual switching in ambiguous figures. Ambiguous figures are a special class of visual stimuli that can give rise to at least two alternative interpretations. Because the figures themselves stay the same, these stimuli are particularly suitable to study the dynamic changes in our visual apparatus that enable us to see the world in different ways. Recent studies stress the importance of both low-level and high-level processes in switching. We show that these processes lead to (...) switching independently, and that, when they co-occur, they do not occur at exactly the same time.We take these results to indicate that perceptual switching is a radically multiply realizable process, in that various neurological states can instantiate it in a single individual from time to time. We reflect on the consequences of this conclusion for experiential realism, in particular the notion that embodiment misleads us in identifying psychological types. (shrink)

Perceptual judgments result from a dynamic process, but little is known about the dynamics of number‐line estimation. A recent study proposed a computational model that combined a model of trial‐to‐trial changes with a model for the internal scaling of discrete numbers. Here, we tested a surprising prediction of the model—a situation in which children's estimates of numerosity would be better than those of adults. Consistent with the model simulations, task contexts led to a clear developmental reversal: children made more (...) adult‐like, linear estimates when to‐be‐estimated numbers were descending over trials (i.e., backward condition), whereas adults became more like children with logarithmic estimates when numbers were ascending (i.e., forward condition). In addition, adults’ estimates were subject to inter‐trial differences regardless of stimulus order. In contrast, children were not able to use the trial‐to‐trial dynamics unless stimuli varied systematically, indicating the limited cognitive capacity for dynamic updates. Together, the model adequately predicts both developmental and trial‐to‐trial changes in number‐line tasks. (shrink)

We introduce the Relational Blockworld (RBW) as a paradigm for deflating the mysteries associated with quantum non-separability/non-locality and the measurement problem. We begin by describing how the relativity of simultaneity implies the blockworld, which has an explanatory potential subsuming both dynamical and relational explanations. It is then shown how the canonical commutation relations fundamental to non-relativistic quantum mechanics follow from the relativity of simultaneity. Therefore, quantum mechanics has at its disposal the full explanatory power of the blockworld. Quantum mechanics exploits (...) this expanded explanatory capability since event distributions among detectors per the density matrix follow from spacetime relations (symmetry group) alone. Thus, the event distributions of non-relativistic quantum mechanics follow from a blockworld wherein spacetime relations are fundamental. Per RBW "quantum mysteries" are deflated and the implications for consciousness and the perception of temporal flow and absolute becoming are explored. We conclude that given RBW, consciousness is no less fundamental than any "physical" feature of the world such as brain states. Further, active consciousness is needed to explain the illusion that it is a dynamical world and consciousness in its most fundamental state is relational and non-local. (shrink)

We examine changing production relations in the Mexican tequila industry to explore the ways in which large industrial firms are using “reverse leasing arrangements,” a form of contract farming, to extend their control over small agave farmers. Under these arrangements, smallholders rent their parcels to contracting companies who bring in capital, machinery, labor, and other agricultural inputs. Smallholders do not have access to their land, nor do they make any of the management decisions. We analyze the factors that have led (...) some producers to participate in reverse leasing arrangements, while allowing other producers to continue farming independently. In addition, we look at the ways in which farmers are responding to these new production relations and constraints and the strategies that they are using to regain control over the production process. (shrink)

In this paper, we present a time-varying and non-stationary but non-hyperbolic discount function that explains dynamic preference reversal. The new discount function emerges from an analysis of intertemporal consumption and savings choices with mortality risk and an altruistic factor. Our analysis shows that the process of updating survival information may also account for dynamic preference reversal.

Postmodern aestheticism is defined as a way of thinking that privileges the art of continual reversal. The dynamics of reversal operate according to a theoretical model that, historically speaking, has been the vehicle for blatantly masculinist ideologies. This creates problems for feminist thinking that would appropriate the postmodern conception of the subjectivity of the artist or the aestheticist dissolution of the distinction between life and art.

It is commonly thought that there is some tension between the second law of thermodynam- ics and the time reversal invariance of the microdynamics. Recently, however, Jos Uffink has argued that the origin of time reversal non-invariance in thermodynamics is not in the second law. Uffink argues that the relationship between the second law and time reversal invariance depends on the formulation of the second law. He claims that a recent version of the second law due to Lieb and Yngvason (...) allows irreversible processes, yet is time reversal invariant. In this paper, I attempt to spell out the traditional argument for incompatibility between the second law and time reversal invariant dynamics, making the assumptions on which it depends explicit. I argue that this argument does not vary with different versions of the second law and can be formulated for Lieb and Yngvason's version as for other versions. Uffink's argument regarding time reversal invariance in Lieb and Yngvason is based on a certain symmetry of some of their axioms. However, these axioms do not constitute the full expression of the second law in their system. (shrink)

We observe that Schrödinger’s equation may be written as two real coupled Hamilton–Jacobi (HJ)-like equations, each involving a quantum potential. Developing our established programme of representing the quantum state through exact free-standing deterministic trajectory models, it is shown how quantum evolution may be treated as the autonomous propagation of two coupled congruences. The wavefunction at a point is derived from two action functions, each generated by a single trajectory. The model shows that conservation as expressed through a continuity equation is (...) not a necessary component of a trajectory theory of state. Probability is determined by the difference in the action functions, not by the congruence densities. The theory also illustrates how time-reversal symmetry may be implemented through the collective behaviour of elements that individually disobey the conventional transformation (T\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{T}$$\end{document}) of displacement (scalar) and velocity (reversal). We prove that an integral curve of the linear superposition of two vectors can be derived algebraically from the integral curves of one of the constituent vectors labelled by integral curves associated with the other constituent. A corollary establishes relations between displacement functions in diverse trajectory models, including where the functions obey different symmetry transformations. This is illustrated by showing that a (T\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{T}$$\end{document}-obeying) de Broglie-Bohm trajectory is a sequence of points on the (non-T\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathrm{T}$$\end{document}) HJ trajectories, and vice versa. (shrink)

Dynamical systems are mathematical structures whose aim is to describe the evolution of an arbitrary deterministic system through time, which is typically modeled as (a subset of) the integers or the real numbers. We show that it is possible to generalize the standard notion of a dynamical system, so that its time dimension is only required to possess the algebraic structure of a monoid: first, we endow any dynamical system with an associated graph and, second, we prove that such a (...) graph is a category if and only if the time model of the dynamical system is a monoid. In addition, we show that the general notion of a dynamical system allows us not only to define a family of meaningful dynamical concepts, but also to distinguish among a cluster of otherwise tangled notions of reversibility, whose logical relationships are finally analyzed. (shrink)

To answer foundational questions in physics, physicists turn more and more to abstract advanced mathematics, even though its physical significance may not be immediately clear. What if we started to borrow ideas and approaches, with appropriate modifications, from the foundations of mathematics? In this paper we explore this route. In reverse mathematics one starts from theorems and finds the minimum set of axioms required for their derivation. In reverse physics we want to start from laws or more specific results, and (...) find the physical concepts and starting points that recover them. We want to understand what physical results are implied by which physical assumptions. As an example of the technique, we will see six different characterizations of classical mechanics, show that the uncertainty principle depends only on the entropy bound on pure states and recast the third law of thermodynamics in terms of the entropy of an empty system. We believe the approach can provide greater insights into both current and new physical theories, put the physical concepts at the forefront of the discussion and provide a more unified view of physics by highlighting common patterns and ideas across different physical theories. (shrink)

Why did such highly abstract ideas as truth, knowledge, or justice become so important to us? What was the point of coming to think in these terms? This book presents a philosophical method designed to answer such questions: the method of pragmatic genealogy. Pragmatic genealogies are partly fictional, partly historical narratives exploring what might have driven us to develop certain ideas in order to discover what these do for us. The book uncovers an under-appreciated tradition of pragmatic genealogy which cuts (...) across the analytic-continental divide, running from the state-of-nature stories of David Hume and the early genealogies of Friedrich Nietzsche to recent work in analytic philosophy by Edward Craig, Bernard Williams, and Miranda Fricker. However, these genealogies combine fictionalizing and historicizing in ways that even philosophers sympathetic to the use of state-of-nature fictions or real history have found puzzling. To make sense of why both fictionalizing and historicizing are called for, the book offers a systematic account of pragmatic genealogies as dynamic models serving to reverse-engineer the points of ideas in relation not only to near-universal human needs, but also to socio-historically situated needs. This allows the method to offer us explanation without reduction and to help us understand what led our ideas to shed the traces of their practical origins. Far from being normatively inert, moreover, pragmatic genealogy can affect the space of reasons, guiding attempts to improve our conceptual repertoire by helping us determine whether and when our ideas are worth having. (shrink)

The Dynamics of Social Practice -- Introducing Theories of Practice -- Materials and Resources -- Sequence and Structure -- Making and Breaking Links -- Material, Competence and Meaning -- Car-Driving: Elements and Linkages Making Links -- Breaking Links -- Elements Between Practices -- Standardization and Diversity -- Individual and Collective Careers -- The Life of Elements -- Modes of Circulation -- Transportation and Access: Material -- Abstraction, Reversal and Migration: Competence -- Association and Classification: Meaning -- Packing and Unpacking (...) -- Emergence, Disappearance and Persistence -- Recruitment, Defection and Reproduction -- First Encounters: Networks and Communities -- Capture and Commitment: Careers and Carriers -- Collapse and Transformation: The Dynamics of Defection -- Daily Paths, Life Paths and Dominant Projects -- Connections Between Practices -- Bundles and Complexes -- Collaboration and Competition -- Selection and Integration -- Coordinating Daily Life -- Circuits of Reproduction -- Monitoring Practices-as-Performances -- Monitoring Practices-as-Entities -- Cross-Referencing Practices-as-Performances -- Cross-Referencing Practices-as-Entities -- Aggregation -- Elements of Coordination -- Intersecting Circuits -- Representing the Dynamics of Social Practice -- Representing Elements and Practices -- Characterizing Circulation -- Competition, Transformation and Convergence -- Reproducing Elements, Practices and Relations between Them -- Time and Practice -- Space and Practice -- Dominant Projects and Power -- Promoting Transitions in Practice -- Climate Change and Behaviour Change -- Basis of Action -- Processes of Change -- Positioning Policy -- Transferable Lessons -- Practice Theory and Climate Change Policy -- Configuring Elements of Practice -- Configuring Relations between Practices -- Configuring Careers: Carriers and Practices -- Configuring Connections -- Practice Oriented Policy Making. (shrink)

Perceptual learning can be defined as practice-induced improvement in the ability to perform specific perceptual tasks. We previously proposed the Reverse Hierarchy Theory as a unifying concept that links behavioral findings of visual learning with physiological and anatomical data. Essentially, it asserts that learning is a top-down guided process, which begins at high-level areas of the visual system, and when these do not suffice, progresses backwards to the input levels, which have a better signal-to-noise ratio. This simple concept has proved (...) powerful in explaining a broad range of findings, including seemingly contradicting data. We now extend this concept to describe the dynamics of skill acquisition and interpret recent behavioral and electrophysiological findings. (shrink)

Despite growing interest in risks of societal collapse due to anthropogenic climate change, there exists no consensus about how collapse should be understood. In this article, we critically examine existing definitions and argue that none adequately address the challenges for conceptualizing collapse that climate change presents. We therefore propose an alternative conception, which regards collapse as a reduction of collective capacity resulting in a pervasive and difficult-to-reverse loss of basic functionality. Our conception is dynamic in that it focuses on the (...) interrelations of constituent subsystems. It also distinguishes collapse from transformations needed to address climate change and provides insight into the relationship between collapse and sustainability. [Open access]. (shrink)

Dynamical collapse models embody the idea of a physical collapse of the wave function in a mathematically well-defined way. They involve modifications to the standard rules of quantum theory in order to describe collapse as a physical process. This appears to introduce a time reversal asymmetry into the dynamics since the state at any given time depends on collapses in the past but not in the future. Here we challenge this conclusion by demonstrating that, subject to specified model constraints, (...) collapse models can be given a structurally time symmetric formulation in which the collapse events are the primitive objects of the theory. Three different examples of time asymmetries associated with collapse models are then examined and in each case it is shown that the same dynamical rule determining the collapse events works in both the forward and backward in time directions. Any physically observed time asymmetries that arise in such models are due to the asymmetric imposition of initial or final time boundary conditions, rather than from an inherent asymmetry in the dynamical law. This is the standard explanation of time asymmetric behaviour resulting from time symmetric laws. (shrink)

This article compares the growth trajectories of Catholicism and Protestantism in modern China and tackles a puzzle: Why did Catholicism, which maintained a substantial numerical advantage in Chinese converts over Protestantism before 1949, come to lag so far behind Protestantism today? The article identifies three crucial differences in the institutional features of Catholicism and Protestantism, but shows that an institutional argument alone is insufficient to explain their reversal of fortune. It argues that the growth trajectories of Catholicism and Protestantism changed (...) less because their institutional features have experienced major changes, but more because their institutional features played out differently in the sociopolitical contexts of pre-1949 China, Maoist China, and post-Mao China. The article advances a new approach that combines the currently dominant institutional argument with a historical perspective that stresses the importance of political forces in order to understand the growth dynamics of religions. It concludes by making some preliminary observations on the generalized patterns of how institutional features of Catholicism and Protestantism play out under different kinds of political structures, shaping their waxing and waning in a global context. (shrink)

It is a familiar point that we can use generic sentences to express generalisations that are tolerant to exceptions and then go on to state those exceptions explicitly. It is a less familiar point that switching the order of the generics has deleterious effects on their felicity. For example, the sequences ‘Ravens are black, but albino ravens aren’t’ is perfectly felicitous and judged to be true, whereas its reverse ‘Albino ravens aren’t black, but ravens are’ is infelicitous and contradictory-sounding. This (...) paper argues that such sequences pose a problem for extant theories of generics: while they have no trouble predicting the felicity of the first sequence of generics, they are unable to explain why reversing the order results in infelicity. I propose to account for these observations by adopting a dynamic semantic theory of generic sentences. (shrink)

Phosphoinositide (PI) phosphatases such as the SH2 domain‐containing inositol 5‐phosphatases 1/2 (SHIP1 and 2) are important signalling enzymes in human physiopathology. SHIP1/2 interact with a large number of immune and growth factor receptors. Tyrosine phosphorylation of SHIP1/2 has been considered to be the determining regulatory modification. However, here we present a hypothesis, based on recent key publications, highlighting the determining role of Ser/Thr phosphorylation in regulating several key properties of SHIP1/2. Since a subunit of the Ser/Thr phosphatase PP2A has been (...) shown to interact with SHIP2, a putative mechanism for reversing SHIP2 Ser/Thr phosphorylation can be anticipated. PI phosphatases are potential target molecules in human diseases, particularly, but not exclusively, in cancer and diabetes. Therefore, this novel regulatory mechanism deserves further attention in the hunt for discovering novel or complementary therapeutic strategies. This mechanism may be more broadly involved in regulating PI signalling in the case of synaptojanin1 or the phosphatase, tensin homolog, deleted on chromosome TEN.Editor's suggested further reading in BioEssays: Pairing phosphoinositides with calcium ions in endolysosomal dynamics Abstract. (shrink)

Figner, Mackinlay, Wilkening, and Weber (2009) developed the Columbia Card Task (CCT) to measure risk-taking attitudes. This tool consists of two versions: in the COLD version the decision maker needs to state in advance how many cards (out of 32) they want to turn over (so called static risk taking), in the HOT version they have the possibility of turning over all 32 cards one-by-one until they decide to finish (dynamic risk taking). We argue that the HOT version confounds an (...) individual’s willingness to accept risk with their beliefs in trend continuation vs. trend reversal in a prognostic task. In two experimental studies we show that people believing in trend continuation (momentum subjects) turn over more cards than those believing in trend reversal (contrarians) in the HOT version of the task. However, this is not the case in the COLD version. Thus, we provide evidence that, when considered as a dynamic risk propensity measure, the number of turned over cards in the HOT version of the CCT is a contaminated measure and reflects two phenomena: (1) risk preference and (2) the decision-maker’s belief in trend continuation. We speculate that other dynamic risk taking measures can also be biased by a momentum strategy. (shrink)

Concerns with the use of engineering approaches in biology have recently been raised. I examine two related challenges to biological research that I call the synchronic and diachronic underdetermination problem. The former refers to challenges associated with the inference of design principles underlying system capacities when the synchronic relations between lower-level processes and higher-level systems capacities are degenerate. The diachronic underdetermination problem regards the problem of reverse engineering a system where the non-linear relations between system capacities and lower-level mechanisms are (...) changing over time. Braun and Marom argue that recent insights to biological complexity leave the aim of reverse engineering hopeless - in principle as well as in practice. While I support their call for systemic approaches to capture the dynamic nature of living systems, I take issue with the conflation of reverse engineering with naïve reductionism. I clarify how the notion of design principles can be more broadly conceived and argue that reverse engineering is compatible with a dynamic view of organisms. It may even help to facilitate an integrated account that bridges the gap between mechanistic and systems approaches. (shrink)

Sex reversal, a mismatch between phenotypic and genetic sex, can be induced by chemical and thermal insults in ectotherms. Therefore, climate change and environmental pollution may increase sex‐reversal frequency in wild populations, with wide‐ranging implications for sex ratios, population dynamics, and the evolution of sex determination. We propose that reconsidering the half‐century old theory “Witschi's rule” should facilitate understanding the differences between species in sex‐reversal propensity and thereby predicting their vulnerability to anthropogenic environmental change. The idea is that sex (...) reversal should be asymmetrical: more likely to occur in the homogametic sex, assuming that sex‐reversed heterogametic individuals would produce new genotypes with reduced fitness. A review of the existing evidence shows that while sex reversal can be induced in both homogametic and heterogametic individuals, the latter seem to require stronger stimuli in several cases. We provide guidelines for future studies on sex reversal to facilitate data comparability and reliability. (shrink)

ArgumentAn unusual compass, on which east and west are reversed, provides insight into the dynamics guiding our understanding of artifacts. By examining how such compasses were used in Tokugawa Japan, the benefits they brought, and how users knew how to read them, this article uncovers the cognitive factors that shape our interaction with technology. Building on the methodological approach of thedistributed cognitiontheory, the article claims that reverse compasses allowed the user to conserve cognitive effort, which was particularly advantageous to (...) Tokugawa-period mariners. Moreover, the article shows that even non-professional Tokugawa Japanese had a relatively easy time reading reverse compasses due to similarity between the compasses’ orientation and Tokugawa timekeeping practices. Building on the bodily and cognitive habits they had developed through the practices of keeping time, users could identify and interpret cultural cues embedded in the structure of reverse compasses. (shrink)

People prefer linguistic stimuli with an inward (e.g. BODIKA) over those with an outward articulation dynamic (e.g. KODIBA), a phenomenon known as the articulatory in-out effect. Despite its robustness across languages and contexts, the phenomenon is still poorly understood. To learn more about the effect’s boundary conditions, mental representation, and origin, we crossed the in-out effect with evaluative conditioning research. In five experiments (N = 713, three experiments pre-registered), we systematically paired words containing inward versus outward dynamics with pictures (...) of negative versus positive valence. Although this evaluative conditioning procedure reversed the preference for inward over outward words, this was the case only for words with the same consonant sequences as the conditioned words. For words with inward/outward dynamics but different consonant sequences than the conditioned ones, a regular in-out effect emerged. Also, no preference reversal at all emerged for the conditioned consonant sequences when the contingency between single consonants at specific positions and positive/negative valence was zero. Implications of these findings for the in-out effect and evaluative conditioning are discussed. (shrink)

The problem of the direction of time is reconsidered in the light of a generalized version of the theory of abstract deterministic dynamical systems, thanks to which the mathematical model of time can be provided with an internal dynamics, solely depending on its algebraic structure. This result calls for a reinterpretation of the directional properties of physical time, which have been typically understood in a strictly topological sense, as well as for a reexamination of the theoretical meaning of the (...) widespread time-reversal invariance of classical physical processes. (shrink)

It is standardly believed that the generally time-reversal symmetric fundamental laws of physics themselves cannot explain the apparent asymmetry of time. In particular, it is believed that CP violation is of no help. In this paper, I want to push back against a quick dismissal of CP violation as a potential source for the arrow of time and argue that it should be taken more seriously for conceptualising time in physics. I first recall that CP violation is a key feature (...) of our best physical theory which also has large-scale explanatory import regarding the matter-antimatter asymmetry of the universe. I then investigate how CP violation may help to explain the directionality of time. I argue that accounts à la Maudlin that posit an intrinsic fundamental direction of time are not convincing and instead propose to utilise recent results from work on the dynamical approach to relativity theory. (shrink)

In his recent book, Time and Chance, David Albert claims that by positing that there is a uniform probability distribution defined, on the standard measure, over the space of microscopic states that are compatible with both the current macrocondition of the world, and with what he calls the “past hypothesis”, we can explain the time asymmetry of all of the thermodynamic behavior in the world. The principal purpose of this paper is to dispute this claim. I argue that Albert's proposal (...) fails in his stated goal—to show how to use the time‐reversible dynamics of Newtonian physics to “underwrite the actual content of our thermodynamic experience” (Albert 2000, 159). Albert's proposal can satisfactorily explain why the overall entropy of the universe as a whole is increasing, but it does not and cannot explain the increasing entropy of relatively small, relatively short‐lived systems in energetic isolation without making use of a principle that leads to reversibility objections. (shrink)

In this précis of The Practical Origins of Ideas: Genealogy as Conceptual Reverse-Engineering (OUP 2021), I summarize the key claims of the book. The book describes, develops, and defends an underappreciated methodological tradition: the tradition of pragmatic genealogy, which aims to identify what our loftiest and most inscrutable conceptual practices do for us by telling strongly idealized, but still historically informed stories about what might have driven people to adopt and elaborate them as they did. What marks out this methodological (...) tradition, I argue, is that it synthesizes two genres of philosophical genealogy that are standardly set against each other: state-of-nature fictions on the one hand and patiently documentary historiography on the other. These two genres of genealogy are usually taken to be mutually exclusive and to answer to radically different philosophical interests and temperaments. But I offer a systematic account of a tradition that combines both genres into a single genealogical method, augmenting genealogy’s power and range by harnessing the strengths and possibilities of both genres. (shrink)

Dynamical systems are mathematical objects meant to formally capture the evolution of deterministic systems. Although no topological constraint is usually imposed on their state spaces, there is prima facie evidence that the topological properties of dynamical systems might naturally depend on their dynamical features. This paper aims to prepare the grounds for a systematic investigation of such dependence, by exploring how the underlying dynamics might naturally induce a corresponding topology.

Body feedback is the proprioceptive feedback that denominates the afferent information from position and movement of the body to the central nervous system. It is crucial in experiencing emotions, in forming attitudes and in regulating emotions and behavior. This paper investigates effects of dynamic body feedback on affect and attitudes, focusing on the impact of movement rhythms with smooth vs. sharp reversals as one basic category of movement qualities. It relates those qualities to already explored effects of approach vs. avoidance (...) motor behavior as one basic category of movement shape. Studies 1 and 2 tested the effects of one of two basic movement qualities (smooth vs. sharp rhythms) on affect and cognition. The third study tested those movement qualities in combination with movement shape (approach vs. avoidance motor behavior) and the effects of those combinations on affect and attitudes toward initially valence-free stimuli. Results suggest that movement rhythms influence affect (studies 1 and 2), and attitudes (study 3), and moderate the impact of approach and avoidance motor behavior on attitudes (study 3). Extending static body feedback research with a dynamic account, findings indicate that movement qualities – next to movement shape – play an important role, when movement of the lived body is an independent variable. (shrink)

Phosphoinositide (PI) phosphatases such as the SH2 domain‐containing inositol 5‐phosphatases 1/2 (SHIP1 and 2) are important signalling enzymes in human physiopathology. SHIP1/2 interact with a large number of immune and growth factor receptors. Tyrosine phosphorylation of SHIP1/2 has been considered to be the determining regulatory modification. However, here we present a hypothesis, based on recent key publications, highlighting the determining role of Ser/Thr phosphorylation in regulating several key properties of SHIP1/2. Since a subunit of the Ser/Thr phosphatase PP2A has been (...) shown to interact with SHIP2, a putative mechanism for reversing SHIP2 Ser/Thr phosphorylation can be anticipated. PI phosphatases are potential target molecules in human diseases, particularly, but not exclusively, in cancer and diabetes. Therefore, this novel regulatory mechanism deserves further attention in the hunt for discovering novel or complementary therapeutic strategies. This mechanism may be more broadly involved in regulating PI signalling in the case of synaptojanin1 or the phosphatase, tensin homolog, deleted on chromosome TEN.Editor's suggested further reading in BioEssays: Pairing phosphoinositides with calcium ions in endolysosomal dynamics Abstract. (shrink)

What happens to the causal structure of a world when time is reversed? At first glance it seems there are two possible answers: the causal relations are reversed, or they are not. I argue that neither of these answers is correct: we should either deny that time-reversed worlds have causal relations at all, or deny that causal concepts developed in the actual world are reliable guides to the causal structure of time-reversed worlds. The first option is motivated by the instability (...) of time-reversed dynamical evolutions under interventions. The second option is motivated by a recognition of how contingent structural features of the actual world shape our causal concepts and reasoning strategies. (shrink)

The criminal defendant is presumed innocent and his guilt must be proved beyond reasonable doubt for conviction. On some issues, however, the defendant must prove his innocence on the balance of probabilities to avoid conviction. Commentators have despaired of reconciling reverse burdens with the presumption in a principled way. Andrew Stumer has made a fresh attempt; however, his solution is overly rigid and rule bound. The presumption is engaged in a dynamic enterprise—minimizing the expected cost of error, mistaken acquittals as (...) well as wrongful convictions. Stumer’s fixed criminal standard and stringent restrictions on reverse burdens work against this goal. A more flexible approach is required, reflecting the calculus of error management. Where the cost or probability of wrongful conviction is relatively low, and the cost or probability of mistaken acquittal relatively high, it may be necessary to lower the standard of proof, or even to reverse the burden of proof. To inhibit these strategies is to increase the expected cost of error at trial. (shrink)

We explored the influence of negation on cognitive dynamics, measured using mouse‐movement trajectories, to test the classic notion that negation acts as an operator on linguistic processing. In three experiments, participants verified the truth or falsity of simple statements, and we tracked the computer‐mouse trajectories of their responses. Sentences expressing these facts sometimes contained a negation. Such negated statements could be true (e.g., “elephants are not small”) or false (e.g., “elephants are not large”). In the first experiment, as predicted (...) by the classic notion of negation, we found that negation caused more discreteness in the mouse trajectory of a response. The second experiment induced a simple context for these statements, yet negation still increased discreteness in trajectories. A third experiment enhanced the pragmatic context of sentences, and the discreteness was substantially diminished, with one primary measure no longer significantly showing increased discreteness at all. Traditional linguistic theories predict rapid shifts in cognitive dynamics occur due to the nature of negation: It is an operator that reverses the truth or falsity of an interpretation. We argue that these results support both propositional and contextual accounts of negation present in the literature, suggesting that contextual factors are crucial for determining the kind of cognitive dynamics displayed. We conclude by drawing broader lessons about theories of cognition from the case of negation. (shrink)

We consider metabolic networks with reversible enzymatic reactions. The model is written as a system of ordinary differential equations, possibly with inputs and outputs. We prove the global stability of the equilibrium , using techniques of monotone systems and compartmental matrices. We show that the equilibrium does not always exist. Finally, we consider a metabolic system coupled with a genetic network, and we study the dependence of the metabolic equilibrium with respect to concentrations of enzymes. We give some conclusions (...) concerning the dynamical behavior of coupled genetic/metabolic systems. (shrink)

This paper is about Sobel sequences, which are sequences of counterfactuals that supposedly display two interesting properties: first, they are consistent, as accounted for by the famous Lewis-Stalnaker analysis; but second, they are not consistent in the reverse order, which is not accounted for by Lewis-Stalnaker. I argue that there has been an empirical oversight in the literature on these sequences: there are consistent sequences, and there are irreversible sequences, but no sequence is both. The Lewis-Stalnaker theory neatly captures Sobel (...) sequences, and also captures the inconsistency of Lewis sequences. But there is still a dynamic asymmetry at work with Lewis sequences, which I account for by appeal to the pragmatic phenomenon of imprecision. Lewis sequences seem consistent because they do not belie factual disagreements, but rather metalinguistic disagreements about how precise to be. This also accounts for their irreversibility—such metalinguistic disagreements about the standard of precision are only possible in one direction, as famously observed by Lewis, who observed them in discourses not containing counterfactuals. (shrink)

Widespread acceptance of Hartshorne’s “correction” of Whitehead’s notion of God inhibited continuing exploration of Whitehead’s own vision of God as a single entity in which the physical and mental poles are reversed. As a result, the implications of this reversed concrescence have been paid scant attention. Whitehead himself did little more than hint at the consequences. My thesis is that consideration of a reversed concrescence highlights the essential dynamism of God as a whole, including the primordial nature, and has implications (...) for the provision of initial aims for the world. (shrink)

“There’s Plenty of Room at the Bottom”, said the title of Richard Feynman’s 1959 seminal conference at the California Institute of Technology. Fifty years on, nanotechnologies have led computer scientists to pay close attention to the links between physical reality and information processing. Not all the physical requirements of optimal computation are captured by traditional models—one still largely missing is reversibility. The dynamic laws of physics are reversible at microphysical level, distinct initial states of a system leading to distinct (...) final states. On the other hand, as von Neumann already conjectured, irreversible information processing is expensive: to erase a single bit of information costs ~3 × 10−21 joules at room temperature. Information entropy is a thermodynamic cost, to be paid in non-computational energy dissipation. This paper addresses the problem drawing on Edward Fredkin’s Finite Nature hypothesis: the ultimate nature of the universe is discrete and finite, satisfying the axioms of classical, atomistic mereology. The chosen model is a cellular automaton with reversible dynamics, capable of retaining memory of the information present at the beginning of the universe. Such a CA can implement the Boolean logical operations and the other building bricks of computation: it can develop and host all-purpose computers. The model is a candidate for the realization of computational systems, capable of exploiting the resources of the physical world in an efficient way, for they can host logical circuits with negligible internal energy dissipation. (shrink)

The current study examined whether pigeons could learn to use abstract concepts as the basis for conditionally switching behavior as a function of time. Using a mid-session reversal task, experienced pigeons were trained to switch from matching-to-sample (MTS) to non-matching-to-sample (NMTS) conditional discriminations within a session. One group had prior training with MTS, while the other had prior training with NMTS. Over training, stimulus set size was progressively doubled from 3 to 6 to 12 stimuli to promote abstract concept development. (...) Prior experience had an effect on the initial learning at each of the set sizes but by the end of training there were no group differences, as both groups showed similar within-session linear matching functions. After acquiring the 12-item set, abstract-concept learning was tested by placing novel stimuli at the beginning and end of a test session. Prior matching and non-matching experience affected transfer behavior. The matching experienced group transferred to novel stimuli in both the matching and non-matching portion of the sessions using a matching rule. The non-matching experienced group transferred to novel stimuli in both portions of the session using a non-matching rule. The representations used as the basis for mid-session reversal of the conditional discrimination behaviors and subsequent transfer behavior appears to have different temporal sources. The implications for the flexibility and organization of complex behaviors are considered. (shrink)

Why does time reversal involve two operations, a temporal reflection and the operation of complex conjugation? Why is it that time reversal preserves position and reverses momentum and spin? This puzzle of time reversal in quantum mechanics has been with us since Wigner’s first presentation. In this paper, I propose a new solution to this puzzle. First, it is shown that the standard account of time reversal can be derived based on the assumption that the probability current is reversed by (...) the time reversal transformation. Next, this assumption is justified and the meaning of time reversal is clarified by analyzing the relationship between the rates of change and the instantaneous quantities which determine them. Finally, I explain how the new analysis help solve the puzzle of time reversal in quantum mechanics. (shrink)

In this paper, we analyze an intra-personal game where a decision-maker is summarized by a succession of selves. Selves may (or may not) have conflicting interests, and earlier selves may have imperfect knowledge of the preferences of future selves. At date 1, self-1 chooses a menu, at date 2, the preferences of self-2 realize and self-2 chooses an item from the menu. We show that equilibrium choice is consistent with either a preference for flexibility, a preference for betweenness or a (...) preference for systematic restriction. Overall, the analysis reconciles the decision–theoretic approach of choice over time with the game–theoretic multiple-selves approach. (shrink)

Understanding the dynamics of complex ecosystems is a necessary step to maintain and control them. Yet, reverse-engineering ecological dynamics remains challenging largely due to the very broad class of dynamics that ecosystems may take. Here, this challenge is tackled through symbolic regression, a machine learning method that automatically reverse-engineers both the model structure and parameters from temporal data. How combining symbolic regression with a “dictionary” of possible ecological functional responses opens the door to correctly reverse-engineering ecosystem (...) class='Hi'>dynamics, even in the case of poorly informative data, is shown. This strategy is validated using both synthetic and experimental data, and it is found that this strategy is promising for the systematic modeling of complex ecological systems. (shrink)

Do children’s single words related to motion and change also encode aspects of environmental events highlighted by Talmy’s motion event analysis? If so, these meanings may predict children’s early verb meanings. Analyzing the kinds of meanings expressed in single “dynamic event words” through motion event semantics yields links between early true verbs in sentences and the semantics encoded in these single words. Dynamic event words reflect the sense of temporal and spatial reversibility established in the late sensorimotor period. We propose (...) that these dynamic meanings provide the semantic foundation for the most common verbs included in early sentences, and thus a bootstrap to full development of the verb repertoire. In this study, we followed the spoken language development of five children. We identified dynamic event words as encoding dynamic change in the following dimensions: spatial direction in relation to self; vertical spatial direction; figure/ground relationships; and temporal event sequences. Verbs continuing the semantics previously identified in dynamic event words occurred early and dominated the verb repertoire through 24 months of age. (shrink)

Social media chat groups, such as WeChat and WhatsApp groups, are widely applied in online communication. This research has conducted two studies to examine the individual level and collective level’s opinion dynamics in those groups. The opinion dynamic is driven by two variables, people’s perceived peer support and willingness of opinion expression. The perceived peer support influences the willingness of opinion expression, and the willingness influences the dynamics of real opinion-expression. First, the quasi-experimental study recruited twenty-five participants as (...) the observation group and found that decreasing perceived peer support would significantly increase individuals’ expression willingness to protect his/her opinion. To generalize the individual level findings to a collective level, the second study treated the social media chat groups as an undirected fully-connected social network and simulated people’s opinion expression dynamics with an agent-based model. The simulation indicated that with the help of increased willingness of opinion expression, the minority opinion supporters as a collective did not fall silent but continue to express themselves and increasing willingness of opinion expression would maintain the existence of minority opinion but could not help the minority reverse to the majority. (shrink)

Contract law doctrines can be ranged along various spectra. One of these spectra runs from the static to the dynamic. A contract law doctrine lies at the static pole of this spectrum if its application turns entirely on what occurred at the moment in time when a contract was formed. A contract law doctrine lies at the dynamic pole if its application turns in significant part on a moving stream of events that precede, follow, or constitute the formation of a (...) contract. Another spectrum runs from the binary to the multifaceted. Contract law doctrines are binary if they organize the experience within their scope into only two categories. Contract law doctrines are multifaceted if they organize the experience within their scope into several categories, including one or more intermediate categories. Classical contract law was a rigid, rather than a supple, instrument. Its rules were often responsive to neither the actual objectives of the parties, the actual facts and circumstances of the partiesâ transaction, nor the dynamic character of contracts. Instead, the rules of classical contract law were centered on a single moment in time, the moment of contract formation. accordingly, classical contract law doctrines were almost wholly static and also tended to be binary. The twentieth century witnessed the development of a modern contract law that has largely overthrown classical contract law. This overthrow has occurred in two ways. To begin with, in many cases modern contract law has reversed or fundamentally modified the rules of classical contract law. More important than the overthrow of specific rules of classical contract law, however, has been the overthrow of the deep structure of classical contract law. Where classical contract law had an overriding preference for rules that were objective and standardized, modern contract law has been highly flexible in adopting rules that are individualized and even subjective. Where classical contract law rules were typically binary, modern contract law rules are often multifaceted. Finally, where classical contract law was largely static, modern contact law is, in large part, dynamic. So, for example, static rules of interpretation have been replaced by dynamic rules that take into account events before and after the moment of contract formation; the static legal-duty rule has withered almost completely away, to be largely replaced by a dynamic modification regime that takes into account the value of ongoing reciprocity; a static judicial review of liquidated damages provisions is giving way to a dynamic review that takes account of the actual loss; and static offer-and-acceptance rules have been replaced by dynamic rules, such as the duty to negotiate in good faith. (shrink)

The present study applies a new method for investigating dynamic unconscious processes. The method consists of selection of words from patient interview and test protocols that in the clinicians' judgments capture the patients' conscious symptom experience and the hypothetical unconscious conflict related to the symptom, subliminal and supraliminal presentation of these words, signal analysis of event-related potentials obtained to the word presentations. Eight phobics and three patients suffering from pathological grief reactions served as subjects. A time-frequency ERP analysis revealed that (...) subjects' ERPs classified the unconscious conflict words better subliminally than supraliminally, while the reverse was true for the conscious symptom words = 2.82, p = .011). The relationship between frequency and latency revealed a similar mirror image pattern for the unconscious conflict and conscious symptom words . This method demonstrated that objective, brain-based evidence for unconscious conflict can be obtained. (shrink)