If the Past Hypothesis underlies the arrows of time, what is the status of the Past Hypothesis? In this paper, I examine the role of the Past Hypothesis in the Boltzmannian account and defend the view that the Past Hypothesis is a candidate fundamental law of nature. Such a view is known to be compatible with Humeanism about laws, but as I argue it is also supported by a minimal non-Humean "governing'' view. (...) Some worries arise from the non-dynamical and time-dependent character of the Past Hypothesis as a boundary condition, the intrinsic vagueness in its specification, and the nature of the initial probability distribution. I show that these worries do not have much force, and in any case they become less relevant in a new quantum framework for analyzing time's arrows---the Wentaculus. Hence, the view that the Past Hypothesis is a candidate fundamental law should be more widely accepted than it is now. (shrink)

The Past Hypothesis is the claim that the Boltzmann entropy of the universe was extremely low when the universe began. Can we make sense of this claim when *classical* gravitation is included in the system? I first show that the standard rationale for not worrying about gravity is too quick. If the paper does nothing else, my hope is that it gets the problems induced by gravity the attention they deserve in the foundations of physics. I then try (...) to make plausible a very weak claim: that there is a well-defined Boltzmann entropy that *can* increase in *some* interesting self-gravitating systems. More work is needed before we can say whether this claim answers the threat to the standard explanation of entropy increase. (shrink)

I argue that explanations for time asymmetry in terms of a ‘Past Hypothesis’ face serious new difficulties. First I strengthen grounds for existing criticism by outlining three categories of criticism that put into question essential requirements of the proposal. Then I provide a new argument showing that any time-independent measure on the space of models of the universe must break a gauge symmetry. The Past Hypothesis then faces a new dilemma: reject a gauge symmetry and introduce (...) a distinction without difference or reject the time independence of the measure and lose explanatory power. (shrink)

It has become something of a dogma in the philosophy of science that modern cosmology has completed Boltzmann's program for explaining the statistical validity of the Second Law of thermodynamics by providing the low entropy initial state needed to ground the asymmetry in entropic behavior that underwrites our inference about the past. This dogma is challenged on several grounds. In particular, it is argued that it is likely that the Boltzmann entropy of the initial state of the universe is (...) an ill-defined or severely hobbled concept. It is also argued that even if the entropy of the initial state of the universe had a well-defined, low value, this would not suffice to explain why thermodynamics works as well as it does for the kinds of systems we care about. Because the role of Boltzmann entropy in our inferences to the past has been vastly overrated, the failure of the Boltzmann program does not pose a serious problem for our knowledge of the past. But it does call a different explanation of why thermodynamics works as well as it does. A suggestion is offered for a different approach. (shrink)

I attempt to get as clear as possible on the chain of reasoning by which irreversible macrodynamics is derivable from time-reversible microphysics, and in particular to clarify just what kinds of assumptions about the initial state of the universe, and about the nature of the microdynamics, are needed in these derivations. I conclude that while a “Past Hypothesis” about the early Universe does seem necessary to carry out such derivations, that Hypothesis is not correctly understood as a (...) constraint on the early Universe’s entropy. (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)

It is often said that the world is explained by laws of nature together with initial conditions. But does that mean initial conditions don’t require further explanation? And does the explanatory role played by initial conditions entail or require that time has a preferred direction? This chapter looks at the use of the ‘initialness defence’ in physics, the idea that initial conditions are intrinsically special in that they don’t require further explanation, unlike the state of the world at other times. (...) Such defences commonly assume a primitive directionality of time to distinguish between initial and final conditions. Using the case study of the time-asymmetry of thermodynamics and the so-called ‘past hypothesis’ — the hypothesis that the early universe was in a state of very low entropy —, I outline and support a deflationary account of the initialness defence that does not pre- suppose a basic directionality of time, and argue that there is a relevant explanatory asymmetry between initial conditions and the state of systems at other times only if certain causal conditions are satisfied. Hence, the initialness defence is available to those who reject a fundamental direction of time. (shrink)

The past hypothesis is that the entropy of the universe was very low in the distant past. It is put forward to explain the entropic arrow of time but it has been suggested. The emperor’s new mind. London:Vintage Books; Penrose, R.. Annals of the New York Academy of Sciences, 571, 249–264; Price, H.. In S. F. Savitt, Times’s arrows today. Cambridge: Cambridge University Press; Price, H.. Time’s arrow and Archimedes’ point. Oxford: Oxford University Press; Price, H.. In (...) C. Hitchcock, Contemporary debates in philosophy of science. Oxford: Blackwell]) that it is itself in need of explanation. It has also been suggested that cosmic inflation could provide the explanation, but Price raises a serious objection to this suggestion, which has otherwise received very little attention in the philosophical literature. Price points out that the standard inflationary explanation involves a double standard: although the evolution of the universe described by the inflationary model seems natural from the standard temporal perspective it looks highly unnatural from the reversed temporal perspective. The main purpose of this paper is to propose a novel form of the inflationary explanation that avoids this objection. It is argued that the inflationary model would not involve a double standard if we construct the model with a global “boundary” condition instead of a conventional boundary condition: if we assume that the universe is as generic as possible overall, rather than as generic as possible at some given point as is assumed in the standard inflationary model. This novel form of the inflationary explanation is then compared with Price’s 1996 preferred explanation, a version of the so-called “Weyl hypothesis”. (shrink)

There is a paradox in the standard model of cosmology. How can matter in the early universe have been in thermal equilibrium, indicating maximum entropy, but the initial state also have been low entropy (the “past hypothesis"), so as to underpin the second law of thermodynamics? The problem has been highly contested, with the only consensus being that gravity plays a role in the story, but with the exact mechanism undecided. In this paper, we construct a well-defined mechanical (...) model to study this paradox. We show how it reproduces the salient features of standard big-bang cosmology with surprising success, and we use it to produce novel results on the statistical mechanics of a gas in an expanding universe. We conclude with a discussion of potential uses of the model, including the explicit computation of the time-dependent coarse-grained entropies needed to investigate the past hypothesis. (shrink)

A striking feature of our world is that we only seem to have records of the past. To explain this ‘record asymmetry’, Albert and Loewer claim that the Past Hypothesis induces a narrow probability density over the world’s possible past macrohistories, but not its future macrohistories. Because we’re indirectly acquainted with this low-entropy initial macrostate, our observations of records allow us to exploit the associated narrow density to infer the past. I will argue that Albert (...) and Loewer cannot make sense of why this probabilistic structure exists without falling back on the very records they wish to explain. To avoid this circularity, I offer an alternative account: the ‘fork asymmetry’ explains the record asymmetry, and this in turn explains the narrow density—not vice versa. (shrink)

Many philosophers sympathetic with a Humean understanding of laws of nature have thought that, in the final analysis, the fundamental laws will include not only the traditional dynamical equations, but also two additional principles: the Past Hypothesis and the Statistical Postulate. The former says that the universe began in a particular very-low-entropy macrostate M(0), and the latter posits a uniform probability distribution over the microstates compatible with M(0). Such a view is arguably vindicated by the orthodox Humean Best (...) System Account (BSA). However, I argue here that recent developments of the BSA render the Past Hypothesis otiose. In particular, the trend among Humeans toward a more pragmatic view of laws — according to which the best system is the one that is maximally effective at helping creatures like us amplify our information about the world — does not support the idea that the Past Hypothesis is a law of nature. (shrink)

Albert provides a sketch of an entropy account of the causal and counterfactual asymmetries. This paper critically examines a proposal that may be thought to fill in some of the lacunae in Albert’s account.

The Past Hypothesis defended by David Wallace in his 2011 account of macroscopic irreversibility is technically distinct from, but in the same spirit as, that of David Albert in his 2000 book Time and Chance. I am concerned in this essay with the role of objective probability in both accounts, which I find obscure. Most of the analysis will be devoted to the classical treatments by both authors, but a final section will question whether Wallace's quantum version involving (...) unitary dynamics removes this obscurity. (shrink)

If an asymmetry in time does not arise from the fundamental dynamical laws of physics, it may be found in special boundary conditions. The argument normally goes that since thermodynamic entropy in the past is lower than in the future according to the Second Law of Thermodynamics, then tracing this back to the time around the Big Bang means the universe must have started off in a state of very low thermodynamic entropy: the Thermodynamic Past Hypothesis. In (...) this paper, we consider another boundary condition that plays a similar role, but for the decoherent arrow of time, i.e. the subsystems of the universe are more mixed in the future than in the past. According to what we call the Entanglement Past Hypothesis, the initial quantum state of the universe had very low entanglement entropy. We clarify the content of the Entanglement Past Hypothesis, compare it with the Thermodynamic Past Hypothesis, and identify some challenges and open questions for future research. (shrink)

The paper discusses recent proposals by Carroll and Chen, as well as Barbour, Koslowski, and Mercati to explain the arrow of time without a Past Hypothesis, i.e. the assumption of a special initial state of the universe. After discussing the role of the Past Hypothesis and the controversy about its status, we explain why Carroll's model - which establishes an arrow of time as typical - can ground sensible predictions and retrodictions without assuming something akin to (...) a Past Hypothesis. We then propose a definition of a Boltzmann entropy for a classical N-particle system with gravity, suggesting that a Newtonian gravitating universe might provide a relevant example of Carroll's entropy model. This invites comparison with the work of Barbour, Koslowski, and Mercati that identifies typical arrows of time in a relational formulation of classical gravity on shape space. We clarify the difference between this gravitational arrow in terms of shape complexity and the entropic arrow in absolute spacetime, and work out the key advantages of the relationalist theory. We end by pointing out why the entropy concept relies on absolute scales and is thus not relational. (shrink)

In recent work on the foundations of statistical mechanics and the arrow of time, Barry Loewer and David Albert have developed a view that defends both a best system account of laws and a physicalist fundamentalism. I argue that there is a tension between their account of laws, which emphasizes the pragmatic element in assessing the relative strength of different deductive systems, and their reductivism or funda- mentalism. If we take the pragmatic dimension in their account seriously, then the laws (...) of the special sciences should be part of our best explanatory system of the world, as well. (shrink)

Cosmological boundary conditions for particles and fields are often discussed as a Cauchy problem, in which configurations and conjugate momenta are specified on an “initial” time slice. But this is not the only way to specify boundary conditions, and indeed in action-principle formulations we often specify configurations at two times and consider trajectories joining them. Here, we consider a classical system of particles interacting with short range two body interactions, with boundary conditions on the particles’ positions for an initial and (...) a final time. For a large number of particles that are randomly arranged into a dilute gas, we find that a typical system trajectory will spontaneously collapse into a small region of space, close to the maximum density that is obtainable, before expanding out again. If generalizeable, this has important implications for the cosmological arrow of time, potentially allowing a scenario in which both boundary conditions are generic and also a low-entropy state “initial” state of the universe naturally occurs. (shrink)

In the past, hypothesis testing in medicine has employed the paradigm of the repeatable experiment. In statistical hypothesis testing, an unbiased sample is drawn from a larger source population, and a calculated statistic is compared to a preassigned critical region, on the assumption that the comparison could be repeated an indefinite number of times. However, repeated experiments often cannot be performed on human beings, due to ethical or economic constraints. We describe a new paradigm for hypothesis (...) testing which uses only rearrangements of data present within the observed data set. The token swap test, based on this new paradigm, is applied to three data sets from cardiovascular pathology, and computational experiments suggest that the token swap test satisfies the Neyman Pearson condition. (shrink)

David Albert explains why we can typically influence the future but not the past by appealing to an initial low-entropy state of the universe. And he argues that in the rare cases where we can influence the past, we cannot use this influence to knowingly gain future rewards: so it does not constitute control. I introduce an important new case in which Albert's account implies we can not only influence the past but control it: a case where (...) our actions in the present are reliably correlated with several events in the present and past. To deal with such cases, we need to appeal to epistemic conditions on deliberation: being agents requires our decisions being epistemically undetermined at the time we make them. In a world with the past-hypothesis, this implies that deliberation will typically come prior to decision. Once deliberation in this direction is established, correlations towards the past cannot then be exploited for control. To explain why we cannot effectively control the past, we need to appeal to deliberation, whether as part of a defence of Albert's account, or used independently to explain the asymmetry of control. (shrink)

Many studies have shown that marijuana can negatively affect the cognitive development of adolescents. For some individuals, marijuana use may also initiate opioid use, dose escalation, and opioid use disorder. States that legalize marijuana should help adolescents through regulation of advertising and availability of marijuana-infused edibles. Such policies may assist in protecting neurodevelopment of the adolescent and young adult brain. The federal government should also remove its prohibition of marijuana sales and use, leaving their regulation to state law-makers.

Philosophers of physics have long debated whether the Past State of low entropy of our universe calls for explanation. What is meant by “calls for explanation”? In this article we analyze this notion, distinguishing between several possible meanings that may be attached to it. Taking the debate around the Past State as a case study, we show how our analysis of what “calling for explanation” might mean can contribute to clarifying the debate and perhaps to settling it, thus (...) demonstrating the fruitfulness of this analysis. Applying our analysis, we show that two main opponents in this debate, Huw Price and Craig Callender, are, for the most part, talking past each other rather than disagreeing, as they employ different notions of “calling for explanation”. We then proceed to show how answering the different questions that arise out of the different meanings of “calling for explanation” can result in clarifying the problems at hand and thus, hopefully, to solving them. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:A Hypothesis on the Origin of TradeThe Exchange of Lives for Sacrifice and SexPablo Díaz-Morlán (bio)introductionThe primary objective of this study is to propose a hypothesis regarding the origin of trade that will help to solve the enigma of why human groups, normally each other's enemies, stopped exchanging blows in order to exchange things. The complexity of this crucial step forward in the relationships between hostile primitive (...) groups can be summarized as follows. In order for an exchange to take place, both parties must take part in it voluntarily because they see a mutual benefit in doing so. In turn, both parties should be aware that in order to obtain what interests them, which is closely guarded by the other party, in return, they must hand over what the other party is interested in. The perception of the interest of the other plays a crucial role in trade, both today and in its origins. The next step to be taken after a successful initial exchange was its consolidation, after it had been proved that it mutually benefited groups who had, until then, been enemies. Once established, this pacific exchange would have diversified considerably and its complexity would have increased significantly. An added [End Page 165] advantage, which was unexpected but real, was that its subsequent usefulness in curbing violence contributed to its growing expansion. The emergence of a comparative advantage in the groups that adopted trade would have guaranteed their future progress with respect to those that continued to systematically adopt violent conduct toward their neighbors.1Throughout this study, we will come across the old idea that the market prevents war. Without a doubt, trade and war between individuals and groups are closely connected, but the boundaries between them are fuzzy and their demarcation has proven elusive to researchers. Albert Hirschman studied the intellectual climate in the seventeenth and eighteenth centuries in favor of trade and the express declaration of Montesquieu that "peace is the natural effect of trade."2 Since then, this idea has gained ground among researchers of economics and other fields of knowledge. In L'enfer des choses and subsequent works, Jean-Pierre Dupuy and Paul Dumouchel defend that the economy (the market) is a substitute for the sacred, containing violence through violent means. The market contains violence in the two senses of the term contain: It holds it and curbs it; it is both the poison and the remedy. The consumer society makes all objects available to everyone and in this way deactivates mimetic rivalry, deferring violent conflicts. But it is only a temporary remedy. In the words of Girard, "It is always necessary to find new toys."3Following the path initiated by Dumouchel and Dupuy, with their criticism of the free market economy and their proposal for a new notion of scarcity, in his text The Empire of Value, André Orléan claims that money is at the origin of the market. My analysis alludes to a moment prior to that established by Orléan. He maintains that he does not contemplate the historical origin of money but instead uses the expression "the conceptual origin of money." In fact, when he defends the essential monetary base of the market, he refers to an already developed market system, that is, an economic system for which the operation is structured around the institution of the market.4 Mark R. Anspach also criticized the market system in his book À Charge de Revanche. This author proposes the transcending of the perverse logic of vengeance that defines both war and the market that transforms it into a positive reciprocity based on the gift. This constitutes a type of shift away from looking at the past (settling old accounts) to looking toward the future, embracing gratitude, which gives rise to the initial gesture of giving.5 This study analyzes a time prior to that examined by Orléan and Anspach. It was the moment of hominization, that is, mimicry, the subsequent violence that threatened the survival of human groups and, as we will seek to explain, the market as an institution that has accompanied humankind since its conformation as a species... (shrink)

This paper -distinguishes between the Hypothesis of Extended Cognition and the Hypothesis of Embedded Cognition, characterizing them as competitors (both motivated by situated, interactive cognitive processing, with the latter being the more conservative of the two interpretations of the data) -clarifies the relation between content externalism and extended cognition -introduces the problem of cognitive bloat, as part of a critical discussion of Clark and Chalmers's "past-endorsement criterion" (if the criterion is embraced, we privilege the internal, endorsing process (...) -- which looks more like an embedded view -- and if the criterion is rejected, bloat follows) and as a problem for extended views more generally -develops a dilemma critical of Clark and Chalmers's "explanatory kinds" argument for extended mind and cognition (arguing that their reasoning faces serious problems regardless of whether one individuates the kinds in question in a fine-grained or a coarse-grained way) -argues that an appeal to functionalism doesn't resolve the issue -argues for the priority, in debates about extended cognition, of the identification of cognitive systems (e.g., because a functionalist approach can't be applied unless we already know what count as inputs and outputs, which requires having already identified the boundaries of the cognitive system). (shrink)

Current models for RNA synthesis involve an RNA polymerase that tracks along a static template. However, research on chromatin loops suggests that the template slides past a stationary polymerase; individual polymerases tie the chromatin fibre into loops and clusters of polymerases determine the basic structure of the interphase and metaphase chromosome. RNA polymerase is then both a player and a manager of the chromosome loop.

Reconstructing the Past seeks to clarify and help resolve the vexing methodological issues that arise when biologists try to answer such questions as whether human beings are more closely related to chimps than they are to gorillas. It explores the case for considering the philosophical idea of simplicity/parsimony as a useful principle for evaluating taxonomic theories of evolutionary relationships. For the past two decades, evolutionists have been vigorously debating the appropriate methods that should be used in systematics, the (...) field that aims at reconstructing phylogenetic relationships among species. This debate over phylogenetic inference, Elliott Sober observes, raises broader questions of hypothesis testing and theory evaluation that run head on into long standing issues concerning simplicity/parsimony in the philosophy of science. Sober treats the problem of phylogenetic inference as a detailed case study in which the philosophical idea of simplicity/parsimony can be tested as a principle of theory evaluation. Bringing together philosophy and biology, as well as statistics, Sober builds a general framework for understanding the circumstances in which parsimony makes sense as a tool of phylogenetic inference. Along the way he provides a detailed critique of parsimony in the biological literature, exploring the strengths and limitations of both statistical and nonstatistical cladistic arguments. (shrink)

The temporal‐focus hypothesis claims that whether people conceptualize the past or the future as in front of them depends on their cultural attitudes toward time; such conceptualizations can be independent from the space–time metaphors expressed through language. In this paper, we study how Chinese people conceptualize time on the sagittal axis to find out the respective influences of language and culture on mental space–time mappings. An examination of Mandarin speakers' co‐speech gestures shows that some Chinese spontaneously perform (...) class='Hi'>past‐in‐front/future‐at‐back (besides future‐in‐front/past‐at‐back) gestures, especially when gestures are accompanying past‐in‐front/future‐at‐back space–time metaphors (Exp. 1). Using a temporal performance task, the study confirms that Chinese can conceptualize the future as behind and the past as in front of them, and that such space–time mappings are affected by the different expressions of Mandarin space–time metaphors (Exp. 2). Additionally, a survey on cultural attitudes toward time shows that Chinese tend to focus slightly more on the future than on the past (Exp. 3). Within the Chinese sample, we did not find evidence for the effect of participants' cultural temporal attitudes on space–time mappings, but a cross‐cultural comparison of space–time mappings between Chinese, Moroccans, and Spaniards provides strong support for the temporal‐focus hypothesis. Furthermore, the results of Exp. 2 are replicated even after controlling for factors such as cultural temporal attitudes and age (Exp. 3), which implies that linguistic sagittal temporal metaphors can indeed influence Mandarin speakers' space–time mappings. The findings not only contribute to a better understanding of Chinese people's sagittal temporal orientation, but also have additional implications for theories on the mental space–time mappings and the relationship between language and thought. (shrink)

Past life regression therapy is used by some physicians in cases with some mental diseases. Anxiety disorders, mood disorders, and gender dysphoria have all been treated using life regression therapy by some doctors on the assumption that they reflect problems in past lives. Although it is not supported by psychiatric associations, few medical associations have actually condemned it as unethical. In this article, I argue that past life regression therapy is unethical for two basic reasons. First, it (...) is not evidence-based. Past life regression is based on the reincarnation hypothesis, but this hypothesis is not supported by evidence, and in fact, it faces some insurmountable conceptual problems. If patients are not fully informed about these problems, they cannot provide an informed consent, and hence, the principle of autonomy is violated. Second, past life regression therapy has the great risk of implanting false memories in patients, and thus, causing significant harm. This is a violation of the principle of non-malfeasance, which is surely the most important principle in medical ethics. (shrink)

Why is our knowledge of the past so much more ‘expansive’ (to pick a suitably vague term) than our knowledge of the future, and what is the best way to capture the difference(s) (i.e., in what sense is knowledge of the past more ‘expansive’)? One could reasonably approach these questions by giving necessary conditions for different kinds of knowledge, and showing how some were satisfied by certain propositions about the past, and not by corresponding propositions about the (...) future. I take it that such is the approach of Chapter 6 of Time and Chance (T&C). Here’s another such a proposal, similar to that of, but significantly different from T&C; my purpose in this section is to highlight the differences, by showing how this account fails. (shrink)

Past experience with video games and cognitive abilities have been hypothesized to independently facilitate a greater ability to learn new video games and other complex tasks. The present study was conducted to examine this “learning to learn” hypothesis. We examined the predictive effects of gaming habits and cognitive abilities on learning of two novel video games in 107 participants. One video game was from the action genre, and the other was from the strategy genre. Hours spent gaming per (...) week and working memory were found to specifically predict learning of the novel strategy video game, after controlling for the effects of age, gender, and action game learning. In contrast, self-identification as a “gamer” was the only specific significant predictor of action game learning, after controlling for the effects of age, gender, and strategy game learning. Age of the participant negatively impacted learning of both games; however, the pattern of the predictive relationships on both action and strategy game learning was not moderated by age. Importantly, a preference for the action versus the strategy game genre had no differential effects on learning of the two novel games, nor were there any gender differences in identification as a gamer or genre preference. Findings from this study suggest that while past gaming experience and cognition do appear to influence the learning of novel video games, these effects are selective to the game genre studied and are not as broad as the “learning to learn” model suggests. (shrink)

Non-presentist A-theories of time (such as the growing block theory and the moving spotlight theory) seem unacceptable because they invite skepticism about whether one exists in the present. To avoid this absurd implication, Peter Forrest appeals to the "Past is Dead hypothesis," according to which only beings in the objective present are conscious. We know we're present because we know we're conscious, and only present beings can be conscious. I argue that the dead past hypothesis undercuts (...) the main reason for preferring non-presentist A-theories to their presentist rivals, rivals which straightforwardly avoid skepticism about the present. (shrink)

Over the past three decades, Van Gelder's dynamical hypothesis has been instrumental in reconceptualizing the ways in which perception-action-cognition unfolds over time and in context. Here, I examine how the dynamical approach has enriched the theoretical understanding of social dynamics within cognitive science, with a particular focus on interpersonal coordination. I frame this review around seven principles in dynamical systems: three that are well-represented in interpersonal coordination research to date (emergent behavior, context-sensitive behavior, and attractors) and four that (...) could be useful opportunities for future growth (hysteresis, sensitivity to initial conditions, equifinality, and reciprocal compensation). In addition to identifying specific promising lines of theoretical inquiry, I focus on the significant potential afforded by computationally intensive science—especially in naturally occurring data or trace data. Building on the foundation laid over the past three decades, I argue that looking to increasingly situated and naturalistic settings (and data) is not only necessary to realize the full commitment to the dynamical hypothesis but is also critical to building parsimonious and principled theories of social phenomena. (shrink)

This paper first advances and discusses the hypothesis that so-called “iconic” or (for the auditory sphere) “echoic” memory is actually a form of perception of the past. Such perception is made possible by parallel inputs with differential delays which feed independently into the sensorium. This hypothesis goes well together with a set of related psychological and phenomenological facts, as for example: Sperling’s results about the visual sensory buffer, the facts that we seem to see movement and hear (...) temporal Gestalts, and the fact that we sometimes seem to hear sounds only after they have stopped. In it most simple form, and formulated in the somewhat misleading information processing idiom, my hypothesis says that each one of a number of parallel input lines with different delays feeds into a spatially separate sensory unit. The set of such units then holds information about the immediate past in what one might call a “chronotopic” sensory map. This contrasts with the idea (common in sensory buffer theory) that the received sensory information is kept (while possibly decaying) in the same unit for some time after it occurred. The hypothesis also contradicts the theory that all sensory information passes through the same unit but is then successively passed through a unidirectional chain of separate units, where the past experiences then become represented (the shift register hypothesis). The main advantage of my theory, beside the natural explanations it offers for the above-mentioned kind of phenomena, is that it postulates a parallel – and therefore robust – rather than a serial mechanism for the registering of temporal information. It can of course easily be modified to fit more complex models of the sensory cerebral code(s) as well as of the chronotopic representation as such. -/- In the second part of my poster, I advance a corresponding hypothesis for those motor commands which control brief movements. At closer inspection, most socalled “ballistic” movements do not seem to be truly ballistic (in the sense in which the movement of a cannonball is so) since the brain must exert some kind of feedforward control over the later part of their trajectory. I suggest that this control is at least sometimes realized by means of differentially delayed output from a chronotopic representation of successive segments of the movement. Not only could this be a biologically natural way of ensuring efficient adaptability of the movement; the hypothesis also explains the not uncommon experience of “seeing the whole movement laid out in advance” when it is initiated. (shrink)

In "How Do We Know It Is Now Now?" David Braddon-Mitchell (Analysis 2004) develops an objection to the thesis that the past is real but the future is not. He notes my response to this, namely that the past, although real, is lifeless and (a fortiori?) lacking in sentience. He argues, however, that this response, which I call 'the past is dead hypothesis', is not tenable if combined with 'special relativity'. My purpose in this reply is (...) to argue that, on the contrary, 'special relativity' supports the thesis that the future is unreal. (shrink)

The recent explosion of interest in epigenetics is often portrayed as the dawning of a scientific revolution that promises to transform biomedical science along with developmental and evolutionary biology. Much of this enthusiasm surrounds what we call the epigenetic switch hypothesis, which regards certain examples of epigenetic inheritance as an adaptive organismal response to environmental change. This interpretation overlooks an alternative explanation in terms of coevolutionary dynamics between parasitic transposons and the host genome. This raises a question about whether (...) epigenetics researchers tend to overlook transposon dynamics more generally. To address this question, we surveyed a large sample of scientific publications on the topics of epigenetics and transposons over the past fifty years. We found that enthusiasm for epigenetics is often inversely related to interest in transposon dynamics across the four disciplines we examined. Most surprising was a declining interest in transposons within biomedical science and cellular and molecular biology over the past two decades. Also notable was a delayed and relatively muted enthusiasm for epigenetics within evolutionary biology. An analysis of scientific abstracts from the past twenty-five years further reveals systematic differences among disciplines in their uses of the term epigenetic, especially with respect to heritability commitments and functional interpretations. Taken together, these results paint a nuanced picture of the rise of epigenetics and the possible neglect of transposon dynamics, especially among biomedical scientists. (shrink)

Prout's hypothesis was influential in—if not necessary for—the establishment of the atomic weight of oxygen, a figure conclusively demonstrated in 1895. Ironically, the successful determination of oxygen's weight also led to a final refutation of the hypothesis . But more than this, the end of Prout's hypothesis via the determination of oxygen's atomic weight was due to three fundamental changes that characterized the way chemistry was practised and communicated in the late nineteenth century. First, encyclopaedia‐like presentations of (...) past atomic‐weight investigations became the focus in numerous and influential studies. Second, there was a dramatic change in the way professional publications presented investigations and experiments, characterized by experimental detail and apparatus design at the expense of theoretical discussion. Finally, the production of hydrogen became the focus of research, as it was one of the principal components of any investigation into atomic weights. Here I present Prout's hypothesis in its historical context by focusing on these three developments and their influence on the research of Edward Williams Morley. While doing so I also illustrate the way marginalized scientists were able to take advantage of their otherwise dubious position and participate in an active and important role in atomic‐weight investigations. (shrink)

The Extended Mind Hypothesis (EMH) needs a defence of phenomenal externalism in order to be consistent with an indispensable condition for attributing extended beliefs, concerning the conscious past endorsement of information. However, it is difficult, if not impossible, to envisage such a defence. Proponents ofthe EMH are thus confronted with a difficult dilemma: they either accept absurd attributions of belief, and thus deflate EMH, or incorporate, for compatibility reasons, the conscious past endorsement condition for extended belief attribution, (...) implying a seemingly unavailable defence of phenomenal externalism, and thus risk inconsistency within EMH. Either way, EMH is threatened. (shrink)

The target article explores material culture datasets from three African forager groups. After demonstrating that these modern, contemporary human populations would leave scant evidence of symbolic behaviour or material complexity, it cautioned against using material culture as a barometer for human cognition in the deep past. Twenty-one commentaries broadly support or expand these conclusions. A minority offer targeted demurrals, highlighting (1) the soundness of reasoning from absence; and questioning (2) the “cognitively modern” null; (3) the role of hunter-gatherer ethnography; (...) and (4) the pertinence of the inferential issues identified in the target article. In synthesising these discussions, this reply addresses all four points of demurral in turn, and concludes that there is much to be gained from shifting our null assumptions and reconsidering the probabilistic inferential links between past material culture and cognition. (shrink)

In a quantum universe with a strong arrow of time, we postulate a low-entropy boundary condition to account for the temporal asymmetry. In this paper, I show that the Past Hypothesis also contains enough information to simplify the quantum ontology and define a unique initial condition in such a world. First, I introduce Density Matrix Realism, the thesis that the quantum universe is described by a fundamental density matrix that represents something objective. This stands in sharp contrast to (...) Wave Function Realism, the thesis that the quantum universe is described by a wave function that represents something objective. Second, I suggest that the Past Hypothesis is sufficient to determine a unique and simple density matrix. This is achieved by what I call the Initial Projection Hypothesis: the initial density matrix of the universe is the normalized projection onto the special low-dimensional Hilbert space. Third, because the initial quantum state is unique and simple, we have a strong case for the \emph{Nomological Thesis}: the initial quantum state of the universe is on a par with laws of nature. This new package of ideas has several interesting implications, including on the harmony between statistical mechanics and quantum mechanics, the dynamic unity of the universe and the subsystems, and the alleged conflict between Humean supervenience and quantum entanglement. (shrink)

What new implications does the dynamical hypothesis have for cognitive science? The short answer is: None. The _Behavior and Brain Sciences _target article, “The dynamical hypothesis in cognitive science” by Tim Van Gelder is basically an attack on traditional symbolic AI and differs very little from prior connectionist criticisms of it. For the past ten years, the connectionist community has been well aware of the necessity of using (and understanding) dynamically evolving, recurrent network models of cognition.

This article analyzes the extended mind hypothesis that has been discussed during the past two decades following the article “The Extended Mind” by Andy Clark and David Chalmers. It examines the position of active externalism and notes the shortcomings of the arguments supporting this position as proposed by Clark and Chalmers. It is demonstrated that the cultural-historical psychology developed by Vygotsky represents an alternative means of substantiating the extended mind hypothesis. Interpreting Vygotsky’s position as “active social externalism,” (...) the author contrasts Vygotsky’s theory with the active externalism of Clark and Chalmers, as well as with the classical externalism advocated by Putnam and Burge, showing the advantage of Vygotsky’s approach. This advantage has been seen in the ability of Vygotsky’s active social externalism to avoid the problems faced by other externalist approaches to explaining the mind. (shrink)

If there are fundamental laws of nature, can they fail to be exact? In this paper, I consider the possibility that some fundamental laws are vague. I call this phenomenon 'fundamental nomic vagueness.' I characterize fundamental nomic vagueness as the existence of borderline lawful worlds and the presence of several other accompanying features. Under certain assumptions, such vagueness prevents the fundamental physical theory from being completely expressible in the mathematical language. Moreover, I suggest that such vagueness can be regarded as (...) 'vagueness in the world.' For a case study, we turn to the Past Hypothesis, a postulate that (partially) explains the direction of time in our world. We have reasons to take it seriously as a candidate fundamental law of nature. Yet it is vague: it admits borderline (nomologically) possible worlds. An exact version would lead to an untraceable arbitrariness absent in any other fundamental laws. However, the dilemma between fundamental nomic vagueness and untraceable arbitrariness is dissolved in a new quantum theory of time's arrow. (shrink)

I argue that the Carroll-Chen cosmogonic model does not provide a plausible scientific explanation of the past hypothesis (the thesis that our universe began in an extremely low-entropy state). I suggest that this counts as a welcomed result for those who adopt a Mill-Ramsey-Lewis best systems account of laws and maintain that the past hypothesis is a brute fact that is a non-dynamical law.

In the Refutation of Idealism, Kant aims to defeat the Cartesian radical skeptical hypothesis that empirical reality might not exist and we cannot have knowledge of it. Kant intends to demonstrate that conscious experience presupposes direct experience of empirical reality. This paper presents new challenges to the conclusions Kant reaches in the Refutation. Kant’s argument turns on the claim that the past must exist, and my challenges concern the possibility that there is no past.

In a quantum universe with a strong arrow of time, it is standard to postulate that the initial wave function started in a particular macrostate---the special low-entropy macrostate selected by the Past Hypothesis. Moreover, there is an additional postulate about statistical mechanical probabilities according to which the initial wave function is a ''typical'' choice in the macrostate. Together, they support a probabilistic version of the Second Law of Thermodynamics: typical initial wave functions will increase in entropy. Hence, there (...) are two sources of randomness in such a universe: the quantum-mechanical probabilities of the Born rule and the statistical mechanical probabilities of the Statistical Postulate. I propose a new way to understand time's arrow in a quantum universe. It is based on what I call the Thermodynamic Theories of Quantum Mechanics. According to this perspective, there is a natural choice for the initial quantum state of the universe, which is given by not a wave function but by a density matrix. The density matrix plays a microscopic role: it appears in the fundamental dynamical equations of those theories. The density matrix also plays a macroscopic / thermodynamic role: it is exactly the projection operator onto the Past Hypothesis subspace. Thus, given an initial subspace, we obtain a unique choice of the initial density matrix. I call this property "the conditional uniqueness" of the initial quantum state. The conditional uniqueness provides a new and general strategy to eliminate statistical mechanical probabilities in the fundamental physical theories, by which we can reduce the two sources of randomness to only the quantum mechanical one. I also explore the idea of an absolutely unique initial quantum state, in a way that might realize Penrose's idea of a strongly deterministic universe. (shrink)

Two of the most difficult problems in the foundations of physics are (1) what gives rise to the arrow of time and (2) what the ontology of quantum mechanics is. I propose a unified 'Humean' solution to the two problems. Humeanism allows us to incorporate the Past Hypothesis and the Statistical Postulate into the best system, which we then use to simplify the quantum state of the universe. This enables us to confer the nomological status to the quantum (...) state in a way that adds no significant complexity to the best system and solves the ''supervenient-kind problem'' facing the original version of the Past Hypothesis. We call the resultant theory the Humean unification. It provides a unified explanation of time asymmetry and quantum entanglement. On this theory, what gives rise to time's arrow is also responsible for quantum phenomena. The new theory has a separable mosaic, a best system that is simple and non-vague, less tension between quantum mechanics and special relativity, and a higher degree of theoretical and dynamical unity. The Humean unification leads to new insights that can be useful to Humeans and non-Humeans alike. (shrink)

It is provocative, but not uncommon, to compare the work of art to a plant. Art is inseparable from the aim to pass on knowledge to future generations, just as plants strive to reproduce. This paper forwards the art-plant hypothesis that views works of art and plants not only as structurally similar, but teleologically united. We look to two models of art to test this hypothesis: earthworks of the land art movement, and the ancient Greek concept of craft (...) or techne. Plant grafting serves as an example artform that is instructive for crafting a more sustainable world. We approach plant grafting as a sustainable technology in an age of genetic monopolization, and as a powerful metaphor for our common roots and responsibility to create a better world. (shrink)

Psychedelics are experiencing a renaissance in mental healthcare. In recent years, more and more early phase trials on psychedelic-assisted therapy have been conducted, with promising results overall. However, ethical analyses of this rediscovered form of treatment remain rare. The present paper contributes to the ethical inquiry of psychedelic-assisted therapy by analysing the ethical implications of its therapeutic mechanisms proposed by the relaxed beliefs under psychedelics (REBUS) hypothesis. In short, the REBUS hypothesis states that psychedelics make rigid beliefs revisable (...) by increasing the influence of bottom-up input. Put differently, patients become highly suggestible and sensitive to context during a psychedelic session, amplifying therapeutic influence and effects. Due to that, patients are more vulnerable in psychedelic-assisted therapy than in other therapeutic interventions; they lose control during a psychedelic session and become dependent on the therapeutic setting (including the therapist). This enhanced vulnerability is ethically relevant and has been exploited by some therapists in the past. Therefore, patients in current research settings and starting mainstream medical settings need to be well informed about psychedelics’ mechanisms and their implications to give valid informed consent to treatment. Furthermore, other security measures are warranted to protect patients from the vulnerability coming with psychedelic-assisted therapy. (shrink)

Learning to solve a class of problems can be characterized as a search through a space of hypotheses about the rules for solving these problems. A series of four experiments studied how different learning conditions affected the search among hypotheses about the solution rule for a simple computational problem. Experiment 1 showed that a problem property such as computational difficulty of the rules biased the search process and so affected learning. Experiment 2 examined the impact of examples as instructional tools (...) and found that their effectiveness was determined by whether they uniquely pointed to the correct rule. Experiment 3 compared verbal directions with examples and found that both could guide search. The final experiment tried to improve learning by using more explicit verbal directions or by adding scaffolding to the example. While both manipulations improved learning, learning still took the form of a search through a hypothesis space of possible rules. We describe a model that embodies two assumptions: the instruction can bias the rules participants hypothesize rather than directly be encoded into a rule; participants do not have memory for past wrong hypotheses and are likely to retry them. These assumptions are realized in a Markov model that fits all the data by estimating two sets of probabilities. First, the learning condition induced one set of Start probabilities of trying various rules. Second, should this first hypothesis prove wrong, the learning condition induced a second set of Choice probabilities of considering various rules. These findings broaden our understanding of effective instruction and provide implications for instructional design. (shrink)

Some argue that time’s causal arrow is grounded in an underlying thermodynamic asymmetry. Often, this is tied to Humean skepticism that causes produce their effects, in any robust sense of ‘produce’. Conversely, those who advocate stronger notions of natural necessity often reject thermodynamic reductions of time’s causal arrow. Against these traditional pairings, I argue that ‘reduction-plus-production’ is coherent. Reductionists looking to invoke robust production can insist that there are metaphysical constraints on the signs of objects’ velocities in any state, given (...) other—including far later—states’ properties. The Past Hypothesis may thus be a metaphysical condition, not a physical law. (shrink)