Mitochondrial shape change, brought about by molecules that promote either fission or fusion between individual mitochondria, has been documented in several model systems. However, the deeper significance of mitochondrial shape change has only recently begun to emerge: among others, it appears to play a role in the regulation of cell proliferation. Here, I review the emerging interplay between mitochondrial fission‐fusion components with cell cycle regulatory machineries and how that may impact cell differentiation. Regulation of mitochondrial shape (...) may modulate mitochondrial metabolism and/or energetics to promote crosstalk between signaling components and the cell cycle machinery. Focused research in this area will reveal the exact role of mitochondria in development and disease, specifically in stem cell regulation and tumorigenesis. Such research may also reveal whether and how the endosymbiotic event that gave rise to the mitochondrion was crucial for the evolution of cell cycle regulatory mechanisms in eukaryotes that are absent in prokaryotes. (shrink)

Closest-continuer or best-candidate accounts of persistence seem deeply unsatisfactory, but it’s hard to say why. The standard criticism is that such accounts violate the ‘only a and b’ rule, but this criticism merely highlights a feature of the accounts without explaining why the feature is unacceptable. Another concern is that such accounts violate some principle about the supervenience of persistence facts upon local or intrinsic facts. But, again, we do not seem to have an independent justification for this supervenience claim. (...) Instead, I argue that closest continuer accounts are committed to unexplained correlations between distinct existences, and that this is their fundamental flaw. We can have independent justification for rejecting such correlations, but what the justification is depends upon much broader issues in ontology. There is no one-size-fits all objection to closest-continuer accounts of persistence. (shrink)

Closest‐continuer or best‐candidate accounts of persistence seem deeply unsatisfactory, but it is hard to say why. the standard criticism is that such accounts violate the ‘only a and b’ rule, but this criticism merely highlights a feature of the accounts without explaining why the feature is unacceptable. Another concern is that such accounts violate some principle about the supervenience of persistence facts upon local or intrinsic facts. But, again, we do not seem to have an independent justification for this supervenience (...) claim. Instead, I argue that closest continuer accounts are committed to unexplained correlations between distinct existences, and that this is their fundamental flaw. We can have independent justification for rejecting such correlations, but what the justification is depends upon much broader issues in ontology. There is no one‐size‐fits all objection to closest‐continuer accounts of persistence. (shrink)

In this essay, I defend three Simple Views concerning human beings. First, that the human embryo is, from the one-cell stage onwards, a single unitary organism. Second, that when an embryo twins, it ceases to exist and two new embryos come into existence. And third, that you and I are essentially human organisms. This cluster of views shows that it is not necessary to rely on co-location, or other obscure claims, in understanding human embryogenesis.

ABSTRACT Many philosophers believe in the Block Universe containing all objects and events - those that we intuitively call past, present, and future. But some of those who endorse this ontology of time also believe that objects persist by enduring - by being present in their entirety at all moments at which they exist. This combination of views, the Block Universe with Endurance, has survived the initial assault of the problem of temporary intrinsics and of several later objections. But I (...) argue that the Block Universe with Endurance fails to account for a striking feature of our temporal experience and must be rejected in favor of the Block Universe with Exdurance. (shrink)

In nature, gregarious animals, insects, or bacteria usually exhibit paradoxical behaviors in the form of group fission and fusion, which exerts an important influence on group’s pattern formation, information transfer, and epidemiology. However, the fission-fusion dynamics have received little attention compared to other flocking behavior. In this paper, an intermittent selective interaction based control algorithm for the self-organized fission-fusion behavior of flocking system is proposed, which bridges the gap between the two conflicting behaviors in (...) a unified fashion. Specifically, a hybrid velocity coordination strategy that includes both the egalitarian and selective interactions is proposed, where the egalitarian interaction is to maintain the flock’s order and achieve the fusion behavior while the selective interaction strategy is for the response to external stimulus information and generates the fission behavior. Numerical simulations demonstrate that the proposed control algorithm can realize the self-organized fission-fusion behavior of flocking system under a unified framework. The influences of the main control parameters on the performance of the fission-fusion behavior are also discussed. In particular, the trade-off parameterαbalances the exploration and exploitation behaviors of flocking system and significantly enhances its movement flexibility and environmental adaptivity. (shrink)

Advocates of occasional identity have two ways of interpreting putative cases of fission and fusion. One way—we call it the Creative view—takes fission to involve an object really dividing (or being replicated), thereby creating objects which would not otherwise have existed. The more ontologically parsimonious way takes fission to involve merely the ‘separation’ of objects that were identical before: strictly speaking, no object actually divides or is replicated, no new objects are created. In this paper we (...) recommend the Creative approach as the best way of dealing with certain problem cases involving teletransportation. Our considerations yield novel takes on psychological-continuity theories of personal identity and survival, and on the puzzle of Theseus' ship. (shrink)

It is generally thought that there are certain persons to whose welfare we should give special weight. It is commonly held, for example, that we should give special weight to our own welfare. On the strongest version of this view, we should always give overriding weight to our own welfare, and so, in considering any set of alternatives, we should always prefer the one in which we fare best. Many people would reject this strong view, for two reasons. First, many (...) people would hold that impersonal reasons (such as reasons of total utility) can sometimes outweigh, or at least counterbalance, reasons of self-interest. Further, many people think that reasons deriving from special personal relations can sometimes outweigh, or at least counterbalance, reasons of self-interest. We can, however, formulate a much weaker, and much more plausible, version of the self-interest view that avoids both these problems. Let’s first define a person’s kin as anyone in the person’s extended family (including himself). And let’s define a person’s kith very broadly as anyone with whom that person has ever interacted. We can now formulate the weak version of the self-interest view as follows. (shrink)

The aim of this paper is to provide a proof-theoretic characterization of relevant logics including fusion and fission connectives, as well as Ackermann’s truth constant. We achieve this by employing the well-established methodology of labelled sequent calculi. After having introduced several systems, we will conduct a detailed proof-theoretic analysis, show a cut-admissibility theorem, and establish soundness and completeness. The paper ends with a discussion that contextualizes our current work within the broader landscape of the proof theory of relevant (...) logics. (shrink)

If certain versions of the correspondence theory of truth are correct, then truth can be informatively defined as correspondence to facts; facts would be truth-makers, and we could explain truth in terms of truth-bearers, correspondence, and truth-makers. I explain how slingshot arguments work generally, as collapsing arguments (regardless of their targets). Working through the slingshots of Davidson, and Gödel, I claim that Davidson’s slingshot involves dubitable premises, but that Gödel’s slingshot is terminal to certain versions of the correspondence theory, as (...) it poses a fatal dilemma between what I call fact fission and fact fusion. My claim is that it is impossible to informatively define truth in terms of correspondence to facts. (shrink)

The fusion of law and equity in common law systems was a crucial moment in the development of the modern law. In this volume leading scholars assess the significance of the fusion of law and equity from comparative, doctrinal, historical and theoretical perspectives.

The question of when human life begins is critical in debates related to life issues. While there are a variety of proposals as to how an organism should be defined, many biologists and ethicists, particularly Catholics, have approached this issue by arguing that fertilization defines the beginning of a new organism. Examining the processes of fission and fusion, which take place before gastrulation, provides strong evidence for when human life beings and therefore how it should be defined. Among (...) the four dominant theories, regulative fission and fusion are the best explanations in terms of being the most consistent with the biological data. This explanation of twinning provides compelling evidence that fertilization is not a necessary condition for human generation, although it may be a sufficient condition. While fertilization generates the vast majority of human beings, additional human beings may rarely be generated during fission events. (shrink)

Molecules are transferred to lysosomes, the major, acid pH, digestive compartment in eukaryotic cells, by a complex series of pathways that converge at a late endosome/prelysosomal compartment. Here, we discuss the relationship between this compartment and the lysosome. We propose that lysosomes are maintained within cells by a repeated series of kiss and run, transient fusion and fission processes with the late endosome/prelysosome compartment. Directionality to these processes may be conferred by pH gradients and retrieval mechanisms. The future (...) challenge in testing this and any other proposed hypothesis for lysosomal biogenesis will be the establishment of molecular mechanisms. (shrink)

According to a traditional conception, romantic love is both constant - if someone loves another, they continue to love them - and exclusive - if someone loves another, they love only the other. In this paper, we argue that the essentiality of constancy and exclusivity is incompatible with the possibilities of fission - roughly speaking, of one person becoming two - and fusion - roughly speaking, of two people becoming one. Moreover, if fission or fusion are (...) possible, then constancy and exclusivity are obligatory features of love only if there are moral dilemmas. We conclude by suggesting this casts doubt on the constancy and especially the exclusivity of love. (shrink)

Catholic opponents of abortion and embryonic stem cell research usually base their position on a hylomorphic account of ensoulment at fertilization. They maintain that we each started out as one-cell ensouled organisms. Critics of this position argue that it is plagued by a number of intractable problems due to fission (twinning) and fusion. We're unconvinced that such objections to early ensoulment provide any reason to doubt the coherence of the hylomorphic account. However, we do maintain that a defense (...) of ensoulment at fertilization must deny that we're essentially organisms. (shrink)

One of the standard approaches to the metaphysics of personal identity has some counter-intuitive ethical consequences when combined with maximising consequentialism and a plausible doctrine about aggregation of consequences. This metaphysical doctrine is the so-called ‘multiple occupancy’ approach to puzzles about fission and fusion. It gives rise to a new version of the ‘utility monster’ problem, particularly difficult problems about infinite utility, and a new version of a Parfit-style ‘repugnant conclusion’. While the article focuses on maximising consequentialism for (...) simplicity, the problems demonstrated apply more widely to a range of ethical views, especially flavours of consequentialism. This article demonstrates how these problems arise, and discusses a number of options available in the light of these problems for a consequentialist tempted by a multiple occupancy metaphysics. (shrink)

William Albert Crawford-Frost was a Canadian born philosopher who developed a unique form of idealism that he called the Philosophy of Integration. This he presented in 1906 in a book by that title which he described in the subtitle as An Explanation of the Universe and of the Christian Religion. What I have taken the liberty of calling his Fusion Philosophy is the metaphysical theory outlined in this work as explained and developed further in his two other books, Old (...) Dogma in a New Light, and A New Theory of Evolution, as well as in a number of shorter pamphlets. I am using the term “fusion” rather than “integration” partly to avoid the social and political emphasis which the latter word has since acquired. However, I am not at all unhappy that my term “fusion” calls to mind our developing nuclear technology since, as will be seen, it is an implication of Crawford-Frost’s idealism that the development and application of nuclear fission, as opposed to fusion, is quite literally nothing less than the work of the Devil. This makes Crawford-Frost’s philosophy of some interest to us today, though I think that his unique form of idealism is, in many ways, interesting in itself. (shrink)

One of the standard approaches to the metaphysics of personal identity has some counter‐intuitive ethical consequences when combined with maximising consequentialism and a plausible (though not uncontroversial) doctrine about aggregation of consequences. This metaphysical doctrine is the so‐called ‘multiple occupancy’ approach to puzzles about fission and fusion. It gives rise to a new version of the ‘utility monster’ problem, particularly difficult problems about infinite utility, and a new version of a Parfit‐style ‘repugnant conclusion’. While the article focuses on (...) maximising consequentialism for simplicity, the problems demonstrated apply more widely to a range of ethical views, especially flavours of consequentialism. This article demonstrates how these problems arise, and discusses a number of options available in the light of these problems for a consequentialist tempted by a multiple occupancy metaphysics. (shrink)

Human societies are examined as distinct and coherent groups. This trait is most parsimoniously considered a deeply rooted part of our ancestry rather than a recent cultural invention. Our species is the only vertebrate with society memberships of significantly more than 200. We accomplish this by using society-specific labels to identify members, in what I call an anonymous society. I propose that the human brain has evolved to permit not only the close relationships described by the social brain hypothesis, but (...) also, at little mental cost, the anonymous societies within which such alliances are built. The human compulsion to discover or invent labels to “mark” group memberships may originally have been expressed in hominins as vocally learned greetings only slightly different in function from chimpanzee pant hoots (now known to be society-specific). The weight of evidence suggests that at some point, conceivably early in the hominin line, the distinct groups composed of several bands that were typical of our ancestors came to be distinguished by their members on the basis of multiple labels that were socially acquired in this way, the earliest of which would leave no trace in the archaeological record. Often overlooked as research subjects, these sizable fission-fusion communities, in recent egalitarian hunter-gatherers sometimes 2,000 strong, should consistently be accorded the status of societies, in the same sense that this word is used to describe tribes, chiefdoms, and other cultures arising later in our history. The capacity of hunter-gatherer societies to grow sufficiently populous that not all members necessarily recognize one another would make the transition to larger agricultural societies straightforward. Humans differ from chimpanzees in that societal labels are essential to the maintenance of societies and the processes giving birth to new ones. I propose that anonymous societies of all kinds can expand only so far as their labels can remain sufficiently stable. (shrink)

As endosymbionts, the mitochondria are unique among organelles. This review provides insights into mitochondrial behavior and introduces the idea of a unified collective, an interconnected reticulum reminiscent of the Borg, a fictional humanoid species from the Star Trek television series whereby decisions are made within their network (or “hive”), linked to signaling cascades that coordinate the cross‐talk between mitochondrial and cellular processes (“subspace domain”). Similarly, mitochondrial dynamics are determined by two distinct processes, namely the local regulation of fission/fusion (...) and the global control of their behavior through cellular signaling pathways. Indeed, decisions within the hive provide each mitochondrial unit with autonomous control of their own degradation, whereby mitochondrial fusion is inactivated and they become substrates for autophagy. Decisions within the subspace domain couple signaling pathways involved in the functional integration of mitochondria with complex cellular transitions, including developmental cues, mitosis, and apoptosis. (shrink)

Mitochondrial function is key for maintaining cellular health, while mitochondrial failure is associated with various pathologies, including inherited metabolic disorders and age‐related diseases. In order to maintain mitochondrial quality, several pathways of mitochondrial quality control have evolved. These systems monitor mitochondrial integrity through antioxidants, DNA repair systems, and chaperones and proteases involved in the mitochondrial unfolded protein response. Additional regulation of mitochondrial function involves dynamic exchange of components through mitochondrial fusion and fission. Sustained stress induces a selective autophagy (...) – termed mitophagy – and ultimately leads to apoptosis. Together, these systems form a network that acts on the molecular, organellar, and cellular level. In this review, we highlight how these systems are regulated in an integrated context‐ and time‐dependent network of mitochondrial quality control that is implicated in healthy aging. (shrink)

Dean Zimmerman argues for the existence of souls as they enable us to avoid certain vagueness-inspired, metaphysical puzzles that plague materialist accounts of the person. There are far too many overlapping material thinking candidates for being the referent of “I”. Zimmerman suggests that an emergent soul whose creation is overdetermined by overlapping material entities will avoid the unwelcome overpopulation of physical thinkers. I will argue that parallel problems plague Zimmerman’s emergent dualism, there are too many souls produced where we want (...) just one. (shrink)

This article seeks to identify at what point in hominid evolution language would have become adaptive. It starts by recalling the distinction between kin-selected altruism and reciprocal altruism, noting that the former is characteristic of social insects while the latter is found among some species of social mammal. Reciprocal altruism depends on the exchange of information assuring partners of the other’s continued friendly intent, as in the iterated prisoner’s dilemma. The article focuses on species that practice “fission–fusion”: social (...) behaviour, where the alternation between larger and smaller parties creates greater uncertainty as to individuals’ continued commitment to reciprocity. The greatest uncertainty arises in “atomistic” fission–fusion, where individuals leave and join foraging groups independently. Chimpanzees, bonobos, and human hunter–gatherers practice this type of social behaviour. There is less uncertainty where the smaller social unit is an extended family, as among vampire bats, chacma baboons, and savanna elephants. A comparison of the repertoire of calls and gestures among these species indicates that chimpanzees and bonobos have the largest repertoires. I then point out that, thanks to the higher proportion of meat in the diet, hunter–gatherers must live in far more dispersed communities than chimpanzees or bonobos, yet they practice more complex patterns of cooperation and reciprocity. This, I argue, created a social environment in which language became particularly adaptive. Homo heidelbergensis is identified as the key species in which language could have originated, during the transition between the Lower and Middle Paleolithic. (shrink)

We hypothesize that life began not with the first self‐reproducing molecule or metabolic network, but as a prebiotic ecology of co‐evolving populations of macromolecular aggregates (composomes). Each composome species had a particular molecular composition resulting from molecular complementarity among environmentally available prebiotic compounds. Natural selection acted on composomal species that varied in properties and functions such as stability, catalysis, fission, fusion and selective accumulation of molecules from solution. Fission permitted molecular replication based on composition rather than linear (...) structure, while fusion created composomal variability. Catalytic functions provided additional chemical novelty resulting eventually in autocatalytic and mutually catalytic networks within composomal species. Composomal autocatalysis and interdependence allowed the Darwinian co‐evolution of content and control (metabolism). The existence of chemical interfaces within complex composomes created linear templates upon which self‐reproducing molecules (such as RNA) could be synthesized, permitting the evolution of informational replication by molecular templating. Mathematical and experimental tests are proposed. BioEssays 28: 399–412, 2006. © 2006 Wiley Periodicals, Inc. (shrink)

Die meisten Tiere unterhalten soziale Beziehungen, aber nicht alle Tiere sind soziale Tiere. Soziale Tiere interagieren jenseits der Reproduktion auf vielfältige Weise mit ihren Artgenossen. Manche soziale Tiere leben in dauerhaften Gemeinschaften, wobei einige dieser Tiere komplexe und dynamische Gemeinschaften bilden. In sogenannten ›Fission-fusion-Gemeinschaften‹ wechseln Größe und Zusammensetzung der Gruppen je nach Tätigkeit. So trennen sich die Tiere zur Nahrungssuche oder sind in Kleingruppen unterwegs, um z. B. für den Schlaf wieder zusammenzukommen. Bei Elefanten, Affen, Delfinen und Raubtieren (...) können Individuen zeitlich stabile soziale Beziehungen unterhalten, obwohl sie in Fission-fusion-Gemeinschaften leben. So leben Bechsteinfledermäuse in solchen Gesellschaften und unterhalten stabile individuelle Beziehungen unabhängig von Alter, Größe, Reproduktionserfolg und Verwandtschaftsgrad; in großen Fledermauskolonien können sich stabile Untergruppen bilden, wobei der zeitlich stabile Kontakt zwischen diesen Untergruppen durch ältere Fledermäuse hergestellt wird. Wie können soziale Verhaltensmuster wie die Bildung von Fission-fusion-Gemeinschaften bzw. zeitlich stabile Relationen zwischen Individuen biologisch erklärt werden? Offenbar hat das Leben in Gruppen ökologische Vorteile, indem es z. B. das Risiko verringert zur Raubtierbeute zu werden. Allerdings hat die Bildung von Gruppen auch soziale Vorteile, indem sie zum Beispiel die Möglichkeit für Reproduktion erhöht. (shrink)

The paper develops a new holistic theory of the word by integrating semiotic, linguistic, and psychological perspectives and introduces the Cogitative-Sensory Word Model, the CogSens Model, that unites the human mind and body. Saussure’s two-sided sign is replaced by a Peirce-inspired three-sided conception in which the expression unit mediates two content units, namely, an idea content connected to the human mind and an image content linked to the human body. It is argued that it is the word that makes human (...) language a unique tool of communication. Moreover, it is demonstrated how words interact with grammar to create an utterance. Finally, it is suggested that speech perception, i.e., fission of idea and image content, is the mirror image of speech production, i.e., fusion of idea and image content. (shrink)

Studying the similarities and differences in socio-communicative behavior between chimpanzees and bonobos is critical to increasing our understanding of the evolution of human sociality and communication. Both species rely heavily on the use of vocalizations during communicative interactions, although the form and function of these signals may vary between the two ape species. For example, bonobo vocalizations seem to be structurally more complex than those produced by chimpanzees, and calls seem to be directed to individuals not in immediate physical proximity. (...) Both species, however, make use of communicative signals from different modalities concurrently, particularly vocalizations and manual gestures. However, this multimodal communication is more commonly observed in chimpanzees when compared to bonobos, who more frequently use vocalizations exclusively, without signals from additional modalities. In addition, there are a number of marked differences in social characteristics between the two species. Though both species exhibit fission–fusion behavior, chimpanzees do so more often, potentially as a result of their habitat profile and foraging strategies. Differences also exist in terms of dominance and aggression. Chimpanzees live in largely patriarchal societies with strong male–male bonds, whereas bonobos tend to be matriarchal with strong female–female bonds. These differences in communicative and social characteristics are thought to be linked to the ecology of the respective habitats of the two apes and their strategies for resource exploitation. In all likelihood, similarities in feeding ecology played a crucial role in selecting for the advanced cognitive abilities of both species—e.g., producing meaningful communicative signals, regulating competition and group cohesion, and making and utilizing tools to aid in foraging. Similarly, differences in their respective habitats may have led to selection for characteristics resulting in the behavioral differences observed today between the two species. Therefore, a clearer understanding of the similarities and differences between the two species most closely related to humans will provide valuable information into our own evolution by elucidating those characteristics shared among humans and our ape ancestors and those derived in the hominin lineage. (shrink)

Many philosophers believe that identity through time cannot depend on features extrinsic to the relata and relations between them. This goes with the view that one must deny identity in cases for which there is a ‘duplication case’-a case just like the first, but for an additional, ‘external’ element which provides an equal or better ‘candidate’ for identity with one of the relata. Such friends of intrinsicness cannot remedy the failure of continuity of function/form to be one-one by non-branching or (...) closest competitor clauses. The obvious intrinsic approach-perhaps taken for granted-appeals to considerations of quantity of matter, requiring over 50% shared matter between identicals . But this rules out plausible cases of halving and doubling for which there are not duplication cases. After bringing out this problem, I ask what makes duplication cases possible, and use this to formulate an intrinsic condition which allows identity whenever there is continuity of function, but no threat to intrinsic ness via duplication cases. (shrink)

Barry Dainton presents a fascinating new account of the self, the key to which is experiential or phenomenal continuity. Provided our mental life continues we can easily imagine ourselves surviving the most dramatic physical alterations, or even moving from one body to another. It was this fact that led John Locke to conclude that a credible account of our persistence conditions - an account which reflects how we actually conceive of ourselves - should be framed in terms of mental rather (...) than material continuity. But mental continuity comes in different forms. Most of Locke's contemporary followers agree that our continued existence is secured by psychological continuity, which they take to be made up of memories, beliefs, intentions, personality traits, and the like. Dainton argues that that a better and more believable account can be framed in terms of the sort of continuity we find in our streams of consciousness from moment to moment. Why? Simply because provided this continuity is not lost - provided our streams of consciousness flow on - we can easily imagine ourselves surviving the most dramatic psychological alterations. Phenomenal continuity seems to provide a more reliable guide to our persistence than any form of continuity. The Phenomenal Self is a full-scale defence and elaboration of this premise. The first task is arriving at an adequate understanding of phenomenal unity and continuity. This achieved, Dainton turns to the most pressing problem facing any experience-based approach: losses of consciousness. How can we survive them? He shows how the problem can be solved in a satisfactory manner by construing ourselves as systems of experiential capacities. He then moves on to explore a range of further issues. How simple can a self be? How are we related to our bodies? Is our persistence an all-or-nothing affair? Do our minds consist of parts which could enjoy an independent existence? Is it metaphysically intelligible to construe ourselves as systems of capacities? The book concludes with a novel treatment of fission and fusion. (shrink)

Dion is a human person, Lefty is his left foot, and Theon is Lefty-Complement, a proper part of Dion. Lefty is annihilated and Dion survives left-footless. After Lefty’s annihilation Theon, if he survives, occupies the same region as Dion. I suggest that this scenario be understood as a fusion case in which Dion and Theon, initially overlapping but distinct, are identical after Lefty’s annihilation and propose an account of proper names that allows us to say that Dion and Theon (...) have ‘become identical’ without commitment to occasional identity or other controversial metaphysical doctrines. The proposed solution employs the semantics developed by Wolfgang Schwarz to address the ‘paradox of occasional identity’, posed by puzzle cases of fission, to deal with the problem of Dion and Theon, a body-minus puzzle. (shrink)

This paper focuses on problems for time travel that specifically concern continuous time-travel to the past, problems to do with potential collisions with past obstacles such as former time-slices of the time traveler herself. These problems have not been discussed nearly as much as other questions about time travel, such as the Grandfather Paradox. Here I focus on discussions by Bernstein, Dowe, Grey and Le Poidevin. After examination, I conclude that only the problems of turning around in time have any (...) merit and present a new proposal of my own for turning around in time without collisions. I assume a Lewisian framework throughout. (shrink)

How do groups of people persist through time? Groups can change their members, locations, and structure. In this paper, I present puzzles of persistence applied to social groups. I first argue that four-dimensional theories better explain the context sensitivity of how groups persist. I then exploit two unique features of the social to argue for the stage theory of group persistence in particular. First, fusion and fission cases actually happen to social groups, and so cannot be marginalized as (...) “pathological.” Second, it is implausible that groups spatially coincide pre-fission. This means that theories that depend on pre-fission spatial coincidence, such as some endurance theories and the worm theory, cannot explain fission cases. All things considered, the stage theory offers the best explanation of how groups persist. (shrink)

There is much to be said for a diachronic or interpersonal individuation of singular modes of presentation (MOPs) in terms of a criterion of epistemic transparency between thought tokens. This way of individuating MOPs has been discussed recently within the mental files framework, though the issues discussed here arise for all theories that individuate MOPs in terms of relations among tokens. All such theories face objections concerning apparent failures of the transitivity of the ‘same MOP’ relation. For mental files, these (...) transitivity failures most obviously occur because mental files can merge or undergo fission. In this paper I argue that this problem is easily resolved once mental files are properly construed as continuants, whose metaphysics is analogous to that of persons or physical objects. All continuants can undergo fission or fusion, leading to similar transitivity problems, but there are well-established theories of persistence that accommodate this. I suggest that, in particular, the stage theory best suits the purposes of a continuant theory of MOPs. (shrink)

In this paper, we argue for a novel three-dimensionalist solution to the problem of persistence, i.e. cross-temporal identity. We restrict the discussion of persistence to simple substances, which do not have other substances as their parts. The account of simple substances employed in the paper is a trope-nominalist strong nuclear theory, which develops Peter Simons' trope nominalism. Regarding the distinction between three dimensionalism and four dimensionalism, we follow Michael Della Rocca's formulation, in which 3D explains persistence in virtue of same (...) entities and 4D in virtue of distinct entities. SNT is a 3D'ist position because it accounts for the persistence of simple substances in virtue of diachronically identical ‘nuclear’ tropes. The nuclear tropes of a simple substance are necessary for it and mutually rigidly dependent but distinct. SNT explains qualitative change by tropes that are contingent to a simple substance. We show that it avoids the standard problems of 3D: temporal relativization of ontic predication, Bradley's regress and coincidence, fission and fusion cases. The temporal relativization is avoided because of the analysis of temporary parts that SNT gives in terms of temporal sub-location, which is atemporal part–whole relation. (shrink)

Jason Bowers and Meg Wallace have recently argued that those who hold that every individual instantiates a ‘haecceity’ are caught up in a Euthyphro-style dilemma when confronted with familiar cases of fission and fusion. Key to Bowers and Wallace’s dilemma are certain assumptions about the nature of metaphysical explanation and the explanatory commitments of belief in haecceities. However, I argue that the dilemma only arises due to a failure to distinguish between providing a metaphysical explanation of why a (...) fact holds vs. a metaphysical explanation of what it is for a fact to hold. In the process, I also shed light on the explanatory commitments of belief in haecceities. (shrink)

It has been argued that 'brain bisection' data leads us to abandon our traditional conception of personal identity. Nagel has remarked: The ultimate account of the unity of what we call a single mind consists of an enumeration of the types of functional integration that typify it. We know that these can be eroded in different ways and to different degrees. The belief that even in their complete version they can be explained by the presence of a numerically single subject (...) is an i1lusion.l Parfit has adopted a similar position, contending that patients with 'split brains' become two separate 'streams of consciousness' and thus that our normal sense of personal identity, or at least 'what matters' about personal identity is constituted by psychological relations between connected conscious experiences2 It is claimed that in 'split brain' patients certain of the relations are disrupted and that we thus see clearly that the nature of the unity that is normally present does not reside in a single subject with a given identity, but in the connectedness and continuity that normally obtains. Parfit draws on two sources of support for these contentions: the first is the actual events that transpire after a human being is submitted to the operation of sectioning the corpus callosum (or 'brain bisection'), and the second is the imaginative consideration of various scenarios involving graded mental and physical discontinuity, and the 'fission' and 'fusion' of persons. I shall do little more than argue that the actual data will not sustain the interpretation put on them. (shrink)

This paper defends stage theory against the argument from diachronic counting. It argues that stage theorists can appeal to quantifier domain restriction in order to accommodate intuitions about diachronic counting sentences. Two approaches involving domain restriction are discussed. According to the first, domains of counting are usually restricted to stages at the time of utterance. This approach explains intuitions in many cases, but is theoretically costly and delivers wrong counts if diachronic counting is combined with fission or fusion. (...) On the second approach, domains of counting are usually restricted in an indeterminate way, so as to include at most one member of any maximal class of counterpart-interrelated stages (with respect to a certain utterance). This view can accommodate all the relevant intuitions about counting sentences, and it fits well with a new stage-theoretic view of reference that allows speakers to refer to both present and past stages. (shrink)

Symmetric generalized Galois logics (i.e., symmetric gGl s) are distributive gGl s that include weak distributivity laws between some operations such as fusion and fission. Motivations for considering distribution between such operations include the provability of cut for binary consequence relations, abstract algebraic considerations and modeling linguistic phenomena in categorial grammars. We represent symmetric gGl s by models on topological relational structures. On the other hand, topological relational structures are realized by structures of symmetric gGl s. We generalize (...) the weak distributivity laws between fusion and fission to interactions of certain monotone operations within distributive super gGl s. We are able to prove appropriate generalizations of the previously obtained theorems—including a functorial duality result connecting classes of gGl s and classes of structures for them. (shrink)

This paper re-examines the question of whether quirks of early human foetal development tell against the view (conceptionism) that we are human beings at conception. A zygote is capable of splitting to give rise to identical twins. Since the zygote cannot be identical with either human being it will become, it cannot already be a human being. Parallel concerns can be raised about chimeras in which two embryos fuse. I argue first that there are just two ways of dealing with (...) cases of fission and fusion and both seem to be available to the conceptionist. One is the Replacement View according to which objects cease to exist when they fission or fuse. The other is the Multiple Occupancy View – both twins may be present already in the zygote and both persist in a chimera. So, is the conceptionist position tenable after all? I argue that it is not. A zygote gives rise not only to a human being but also to a placenta – it cannot already be both a human being and a placenta. Neither approach to fission and fusion can help the conceptionist with this problem. But worse is in store. Both fission and fusion can occur before and after the development of the inner cell mass of the blastocyst – the entity which becomes the embryo proper. The idea that we become human beings with the arrival of the inner cell mass leads to bizarre results however we choose to accommodate fission and fusion. (shrink)

In this essay, I attempt to provide answers to the following four queries concerning the metaphysics of early human embryogenesis. (1) Following its first cellular fission, is it coherent to claim that one and only one of two “blastomeric” twins of a human zygote is identical with that zygote? (2) Following the fusion of two human pre-embryos, is it coherent to claim that one and only one pre-fusion pre-embryo is identical with that postfusion pre-embryo? (3) Does a (...) live human being come into existence only when its brain comes into existence? (4) At implantation, does a pre-embryo become a mere part of its mother? I argue that either if things have quidditative properties or if criterialism is false, then queries (1) and (2) can be answered in the affirmative; that in light of recent developments in theories of human death and in light of a more “functional” theory of brains, query (3) can be answered in the negative; and that plausible mereological principles require a negative answer to query (4). (shrink)

Joining an antagonistic phosphoinositide (PtdInsP) kinase and phosphatase into a single protein complex may regulate rapid and local PtdInsP changes. This may be important for processes such as membrane fission that require a specific PtdInsP and that are innately local and rapid. Such a complex could couple vesicle formation, with erasing of the identity of the donor organelle from the vesicle prior to its fusion with target organelles, thus preventing organelle identity intermixing. Coordinating signals are postulated to switch (...) the relative activities of the kinase and phosphatase in a spatio‐temporal manner that matches membrane fission events. The discovery of two such complexes supports this hypothesis. One regulates the interconversion of phosphatidylinositol and PtdIns(3)P by joining the Vps34 PtdIns 3‐kinase and the myotubularin 3‐phosphatases. The other regulates the interconversion between PtdIns(3)P and PtdIns(3,5)P2 through the Fab1/PIKfyve kinase and the Fig4/mFig4 phosphatase. These lipids are essential components of the endosomal identity code. (shrink)

This paper establishes that the occasional identity relation and the contingent identity relation are both non-transitive and as such are not properly classified as identity relations. This is achieved by appealing to cases where multiple fissions and fusions occur simultaneously. These cases show that the contingent and occasional identity relations do not even satisfy the time-indexed and world-indexed versions of the transitivity requirement and hence are non-transitive relations.

Haecceitism is the thesis that, necessarily, in addition to its qualities, each thing has a haecceity or individual essence. The purpose of this paper is to expose a flaw in haecceitism: it entails that familiar cases of fission and fusion either admit of no explanation or else only admit of explanations too bizarre to warrant serious consideration. Because the explanatory problem we raise for haecceitism closely resembles the Euthyphro problem for divine command theory, we refer to our objection (...) as the haecceitic Euthyphro problem, or the Haecceitic Euthyphro for short. We conclude that the objection is decisive against haecceitism. (shrink)

Résumé Les risques induits par le déploiement de l’énergie nucléaire doivent être appréhendés dans le contexte global des besoins d’énergie du système technique pour les siècles qui viennent et des dangers qui s’attachent à une éventuelle pénurie. Le système technique, sur lequel la société humaine repose, s’approvisionne à deux sources d’énergie et à deux seulement : l’énergie solaire, y compris sous ses formes fossiles stockées dans la croûte terrestre – pétrole, gaz, charbon – et l’énergie nucléaire. Les besoins globaux du (...) système technique sont aujourd’hui satisfaits pour environ 80 % par les ressources fossiles, ce qui comporte le risque de détériorer de façon irréversible le climat de la Terre. La « prospérité économique » est construite sur cette situation précaire ; elle est de ce fait menacée par l’épuisement des stocks. L’énergie nucléaire se présente sous deux formes : la fission et la fusion. Les débats sur les risques nucléaires sont centrés sur la fission. L’énergie de fusion n’est pas encore techniquement disponible et ne le sera peut-être jamais. Les risques revêtent deux aspects : l’émission catastrophique de matière radioactive par un accident dans le fonctionnement d’un réacteur et le stockage à long terme des déchets nucléaires. Au-delà des confrontations politiques et idéologiques engendrées par ces deux problèmes, la question du risque nucléaire doit être évaluée dans le cadre général que constituent l’épuisement des ressources fossiles et l’altération du climat engendrée par leur consommation immodérée. La recherche d’une solution à long terme pour l’approvisionnement énergétique a deux aspects : celui des contraintes techniques et celui de l’acceptabilité sociale. C’est un problème d’une extrême complexité et qui appelle la plus grande attention. En ce qui concerne sa dimension sociale, il semble clair que le gavage de l’opinion publique avec quelques slogans rustiques n’apportera pas de contribution positive à une solution de problème global. (shrink)

Humans coordinate their focus of attention with others, either by gaze following or prior agreement. Though the effects of joint attention on perceptual and cognitive processing tend to be examined in purely visual environments, they should also show in multisensory settings. According to a prevalent hypothesis, joint attention enhances visual information encoding and processing, over and above individual attention. If two individuals jointly attend to the visual components of an audiovisual event, this should affect the weighing of visual information during (...) multisensory integration. We tested this prediction in this preregistered study, using the well-documented sound-induced flash illusions, where the integration of an incongruent number of visual flashes and auditory beeps results in a single flash being seen as two (fission illusion) and two flashes as one (fusion illusion). Participants were asked to count flashes either alone or together, and expected to be less prone to both fission and fusion illusions when they jointly attended to the visual targets. However, illusions were as frequent when people attended to the flashes alone or with someone else, even though they responded faster during joint attention. Our results reveal the limitations of the theory that joint attention enhances visual processing as it does not affect temporal audiovisual integration. (shrink)

In his Reasons and Persons, Derek Parfit argues from the possibility of cases of fission and/or fusion of persons that one must reject identity as what matters for personal survival. Instead Parfit concludes that what matters is “psychological connectedness and/or continuity with the right kind of cause,” or what he calls an R-relation. In this paper, I argue that, if one accepts Parfit’s conclusion, one must accept that R-relations are what matter for moral responsibility as well. Unfortunately, it (...) seems that accepting that the R-relation is what matters for both survival and moral responsibility leads to a contradiction. My goal, however, is not merely to point out a problem in Parfit’s account. Instead, I believe that once we understand the basic intuitions which lead to this contradiction, it is clear that there is no fully satisfactory way to account for what matters with respect to survival and moral responsibility. (shrink)

The development of nuclear weapons during the Manhattan Project is one of the most significant scientific events of the twentieth century. This revised and updated 3rd edition explores the challenges that faced the scientists and engineers of the Manhattan Project. It gives a clear introduction to fission weapons at the level of an upper-year undergraduate physics student by examining the details of nuclear reactions, their energy release, analytic and numerical models of the fission process, how critical masses can (...) be estimated, how fissile materials are produced, and what factors complicate bomb design. An extensive list of references and a number of exercises for self-study are included. Links are given to several freely-available spreadsheets which users can use to run many of the calculations for themselves. (shrink)

ABSTRACT This essay tells the story of Perelman and Olbrechts-Tyteca's “dissociation of concepts,” which they introduced in 1958 and is in use as a tool of criticism by many rhetorical critics. The story begins in England with John Locke's development of associative reasoning in 1770 and then moves to France, with Remy de Gourmont extending associative reasoning with the concept of dissociation in 1899. Gourmont's dissociation crosses the Atlantic and is then developed by Kenneth Burke in 1931. In turn, Perelman (...) and Olbrechts-Tyteca absorbed and expanded Locke, Gourmont, and Burke's theories of association and dissociation in 1958. They crafted a tool, the dissociation of concepts, that equips rhetorical reasoning with the capacity to navigate between the promise and perils of fission and fusion. Since 1958, many scholars have made productive use of Perelman and Olbrechts-Tyteca's innovation. The essay concludes with some possible futures for their dissociation of concepts. (shrink)