How different neural crest derivatives differentiate in distinct embryonic locations in the vertebrate embryo is an intriguing issue. Many attempts have been made to understand the underlying mechanism of specific pathway choices made by migrating neural crest cells. In this speculative review we suggest a new mechanism for the regulation of neural crest cell migration patterns in avian and mammalian embryos, based on recent progress in understanding the expression and activity of receptor tyrosine kinases during embryogenesis. Distinct subpopulations of crest‐derived (...) cells express specific receptor tyrosine kinases while residing in a migration staging area. We postulate that the differential expression of receptor tyrosine kinases by specific subpopulations of neural crest cells allows them to respond to localized growth factor ligand activity in the embryo. Thus, the migration pathway taken by neural crest subpopulations is determined by their receptor tyrosine kinase response to the differential localization of their cognate ligand. (shrink)

Evidence is accumulating that individual and environmental factors in childhood and adolescence should be considered when investigating adult health and aging-related processes. The data required for this is gathered by comprehensive long-term longitudinal studies. This article describes the protocol of the Zurich Longitudinal Studies, a set of three comprehensive cohort studies on child growth, health, and development that are currently expanding into adulthood. Between 1954 and 1961, 445 healthy infants were enrolled in the first ZLS cohort. Their physical, motor, cognitive, (...) and social development and their environment were assessed comprehensively across childhood, adolescence, and into young adulthood. In the 1970s, two further cohorts were added to the ZLS and assessed with largely matched study protocols: Between 1974 and 1979, the second ZLS cohort included 265 infants, and between 1970 and 2002, the third ZLS cohort included 327 children of participants of the first ZLS cohort. Since 2019, the participants of the three ZLS cohorts have been traced and invited to participate in a first wave of assessments in adulthood to investigate their current health and development. This article describes the ZLS study protocol and discusses opportunities, methodological and conceptual challenges, and limitations arising from a long-term longitudinal cohort recruited from a study about development in early life. In the future, the ZLS will provide data to investigate childhood antecedents of adult health outcomes and, ultimately, will help respond to the frequent call of scientists to shift the focus of aging research into the first decades of life and, thus, to take a lifespan perspective on aging. (shrink)

In opposition to traditional forms of dualism and monism, the author holds that our bodily self includes certain aspects of otherness. This is shown concerning the phenomenological issues of intentionality, of self-awareness and of intersubjectivity, by emphasizing the dimension of pathos. We are affected by what happens to us before being able to respond to it by acts or actions. Every sense, myself and others are born out of pathos. The original alienness of our own body, including neurological processes, creates (...) shifting degrees of nearness and remoteness, and allows for pathological deviations such as depersonalisation, paranoia or trauma. Such a phenomenology of body crosses the borderlines of different disciplines. (shrink)

We discuss conceptual change and progress within mathematics, in particular how tools, structural concepts and representations are transferred between fields that appear to be unconnected or remote from each other. The theoretical background is provided by the frame concept, which is used in linguistics, cognitive science and artificial intelligence to model how explicitly given information is combined with expectations deriving from background knowledge. In mathematical proofs, we distinguish two kinds of frames, namely structural frames and ontological frames. The interaction between (...) both kinds of frames can drive mathematical interpretation. We first discuss two examples where structural frames (formulaic notation) drive ontological development (the discovery or exploration of mathematical objects). The development of Boole’s Boolean algebra may at first appear as a metaphorical treatment of the (then) new area of logic. In the analysis, we discuss how different (aspects of) certain algebraic frames change in the transfer, how arising difficulties are solved and overall argue that Boole uses the numerical algebra frame as a research template for the discovery of a system for calculations in logic. Following Ifrah, we analyse the discovery of zero as an extension to the number ontology as driven by the development of notation. Both structural and ontological frames are extended and simplified as notation progresses. Finally, we discuss two examples from infinite combinatorics, viz. topological graph theory, and one foundational issue. In both examples, the two simultaneous frames about one object are maintained independently. They motivate different research questions, but may also fruitfully interact: shifting between multiple synchronously maintained perspectives acts as a motor of innovation. The analysis shows how a frame-based approach allows to model how different perspectives drive mathematical innovation because they highlight different aspects, questions and heuristics. (shrink)

Frames are a concept in knowledge representation that explains how the receiver, using background information, completes the information conveyed by the sender. This concept is used in different disciplines, most notably in cognitive linguistics and artificial intelligence. This paper argues that frames can serve as the basis for describing mathematical proofs. The usefulness of the concept is illustrated by giving a partial formalisation of proof frames, specifically focusing on induction proofs, and relevant parts of the mathematical theory within which the (...) proofs are conducted; for the latter, we look at natural numbers and trees specifically. (shrink)

This article critiques Husserl’s idea of grounding through an exploration of his notion of the lifeworld. First, it sketches different senses of the lifeworld in the Crisis and explains in what sense it is taken to be a universal foundation of all sense-formation. Second, it criticizes Husserl’s idea of grounding and shows that it fails because the alleged foundation—namely, the lifeworld as a perceptual world, or rather lifeworldly experience as perception—is inadequately determined. Perception cannot function as a universal foundation because (...) it is always already interpretation. “The groundlessness of sense” means that the process of sense-formation can in no way rest upon an ultimate ground because contingent presuppositions and historical circumstances influence it from the very beginning. The paper concludes by discussing the consequence of this view for the relation between philosophy and sciences. (shrink)

An ethical epoché is required to leave the terrain of a self-evident morality and question its origin. In particular, four fundamental motifs of the ethical dimension are identified: pathos, to be thematised as an alternative to the persistent activist unilateralism; response, which always involves body and soul; diastasis with its stumbles and subtractions; and finally coaffection, in which the social dimension of experience is announced. Ethical behaviour feeds on the magma of pathos, which in turn would be blind and directionless (...) without any ethos. (shrink)

Experience is investigated according to those breaking points where the unexpected surfaces and the surprise of the extraordinary and the alien breaks through. What happens is always in the postponement between pathos and response; this represents the fundamental agreement of a responsive phenomenology: it is never a quiet succession, but always something arriving too early or too late. Threshold experiences such as hesitation, delay, waiting, pausing, stumbling are investigated in this framework.

Living corporeity is the intermediate element between nature and culture, which must be thought of as a reciprocal interconnection, since as corporeal beings we always move on a threshold. In the reflection of the bodily self, a doubling between the living body as a functioning subject and as a material object is revealed; after all, even one's own body sometimes takes on the features of a foreign body, as is the case in the experience of illness. In the technical instrument, (...) the body is prolonged and this highlights the connection between the technique of the thing and the technique of the self; however, despite the gradual autonomisation of the technical element from the living corporeity, there remains what escapes calculation and looms large in the subtraction of the alien. (shrink)

Both Brandom and Wittgenstein see meaning and content as emerging from normative social practices. Wittgenstein says little about the constitution of such norms, other than that they are exhibited in practitioners’ judgements of correctness. In addition, they appear already to be content involving, since the moves whose correctness is in question are moves such as asserting that such and such. In contrast, Brandom says a good deal about the constitution of the norms and promises a reductive programme. The norms are (...) essentially inferential and are instituted in the social practice of attributing commitments and entitlements. In particular, we are urged to see the norm-bound move of assertion as capable of being understood in terms of the normative statuses of commitments and entitlements. Jeremy Wanderer calls this Brandom’s bold conjecture. In this paper I use Wittgenstein’s thinking about normativity to reflect on the defensibility of Brandom’s bold conjecture. (shrink)

Wittgenstein never tells us what Tractarian objects are. He never tells us what Tractarian names are. But we do know that states of affairs are combinations of objects; that propositions are logical pictures; that pictures are facts; and that elementary propositions are combinations of names, which name objects. The logical form of an elementary proposition is the same as that of the state of affairs it represents. So names are objects. The paper investigates the consequences of this glimpse into the (...) nature of objects. (shrink)

Living corporeity is the intermediate element between nature and culture, which must be thought of as a reciprocal interconnection, since as corporeal beings we always move on a threshold. In the reflection of the bodily self, a doubling between the living body as a functioning subject and as a material object is revealed; after all, even one's own body sometimes takes on the features of a foreign body, as is the case in the experience of illness. In the technical instrument, (...) the body is prolonged and this highlights the connection between the technique of the thing and the technique of the self; however, despite the gradual autonomisation of the technical element from the living corporeity, there remains what escapes calculation and looms large in the subtraction of the alien. (shrink)

Through a comparison of the phenomenological motif of the alien and the psychoanalytic motif of the unconscious, a critique is advanced against Cartesian dualism, which recurs today in the natural sciences and in the split of the contemporary individual, divided between spirit and nature, the proper world and the alien world, the inner sphere and the outer sphere. It is a matter of thinking of an original subtraction, an absent presence that begins with ourselves, in a slippage that achieves no (...) synthesis. (shrink)

Introduces the phenomenology of the Other, taking into account the work of Husserl, Merleau-Ponty, Levinas, Schutz, and Derrida, but mostly going back to things themselves.

Antirealism about the past is apparently in conflict with our acceptance of a set of systematic linkages between the truth-values of differently tensed sentences made at different times. Arguments based on acceptance of these so-called truth-value links seem to show that fully accounting for our use of the past and future tenses will involve use of a notion of truth which is not epistemically constrained and is thus antirealistically unacceptable. I elaborate these difficulties through an examination of work by Dummett (...) and Wright. I agree with Wright's rejection of Dummett's proposal but go on to argue that Wright's account fares no better. Building on what I take to be the failure of Wright's account, I offer a solution for the antirealist which diagnoses the problem as stemming from an equivocation in the meanings assigned to the tensed truth predicates. I close by raising a different problem for antirealist accounts of the past, one which is, however, related to more general difficulties for antirealist theories of meaning. (shrink)

Certain anti-realisms about mathematics are distinguished by their taking proof rather than truth as the central concept in the account of the meaning of mathematical statements. This notion of proof which is meaning determining or canonical must be distinguished from a notion of demonstration as more generally conceived. This paper raises a set of objections to Dummett's characterisation of the notion via the notion of a normalised natural deduction proof. The main complaint is that Dummett's use of normalised natural deduction (...) proofs relies on formalisation playing a role for which it is unfit. Instead I offer an alternative account which does not rely on formalisation and go on to examine the relation of proof to canonical proof, arguing that rather than requiring an explicit characterisation of canonical proofs we need to be more aware of the complexities of that relation. (shrink)

The paper undertakes a comparison of the philosophies of Stanley Cavell and Emmanuel L_vinas, focusing on their interpretation of skepticism and the crucial role of the problem of the other or other minds in the works of both. The comparison proceeds in three major steps: first, differences in their respective interpretations of Descartes’ stance on the problem of other minds are discussed. In the second section, Cavell’s examination of the intelligibility of someone else’s pain and L_vinas’ questioning of the sense (...) of suffering are juxtaposed. Finally, the author analyzes their respective treatment of skepticism. This results in the opening of an ethical dimension which grounds the dominating theoretical relationship towards the world and the other human being in epistemology and ontology. The periodical return and irrefutability of skepticism can thus be regarded not only as evidence of the inevitable limitation of knowledge, but as a consequence of the necessarily social or intersubjective structure of subjectivity itself. (shrink)

Reading Cassirer’s philosophy of myth: early signs of Heidegger’s late philosophy? In 1928, Heidegger’s book review of the second volume of Cassirer’s Philosophy of Symbolic Forms (The Mythical Thought) was published in the Deutsche Literaturzeitung. Cassirer’s text date of 1925, hence it is possible that Heidegger had read it even before the publication of Being and Time. What makes both texts worthy of a closer examination is the fact that several central motifs and terms of Heidegger’s later philosophy are already (...) present in these two texts. Heidegger focuses particularly on Cassirer’s reflections on the representation of mana (Mana-Vorstellung) in mythical thinking. This representation involves not only the distinction between the familiar and the unfamiliar, the ‘uncanniness’ or ‘not-at-homeness’ that befalls mightily the Dasein, but also the distinction between the sacred and the profane and that of the four world regions (Weltgegenden) and its organization in form of a cross. Although not everything that Heidegger announces is interpretable as full awareness of the future impact of these traces, one would wonder if the density with which they appear would be mere accident. Thus, the article contributes to the debate on the issue of the emerging of Heidegger’s late thought and its origins which can be traced back to the stage of genesis, or rather, the final draft of Being and Time. (shrink)

In this seminal work, acclaimed philosopher Bernhard Waldenfels deals with the problem of the nature of order after the “shattering of the world,” and the loss of the idea of a universal or fundamental order._ _ Order in the Twilight__ unites phenomenological methodology with recent work on the theory of order, normativity, and dialogue, as well as structuralism and Gestalt theory. Philosophically stringent, it expresses a more optimistic attitude than much modern philosophy, especially deconstruction._ Waldenfels passes the question of (...) order through numerous defining aspects, and concludes that there is not one global order, but rather various conflicting domains of order. Whenever the boundary of a vital or experiential domain is crossed, a discourse speaks at the boundary, not about it, and across a threshold without abolishing it. The rest is rationalization, i.e., an attempt to find a place in the respective order for what is to-be-ordered. But why, the author concludes, should a theory be more unambiguous than reality? _ Order in the Twilight__ is an important book at this time, because it may help lift the humanities out of the skeptical, relativistic disarray in which they have been embroiled in recent decades. Waldenfels does not attempt to dictate what reality should be; rather, he is open to any valid evidences. His book offers a solid footing to the human and social sciences as they seek to escape from deconstructive irrationalism. (shrink)

This chapter covers the traditional role of responsibility, and the possible connections between response and responsibility. These connections are explored through the advance of trust and the surplus of the extraordinary in relation to the Third Party. The idea of responsibility comes from the sphere of juridical law, and has a theological touch. The classical conception presented suffers from a permanent erosion that is reinforced by systemic constraints. Trust is a natural element of every community that is together applied by (...) common aims in life. The phenomenon of trust refers to the bond, the nexus, which holds together the members of a community, creating the requisite solidarity. The term ‘trust’ or ‘confidence’ should not primarily read as a substantive, but as a verb or as the derivative of a verb. Furthermore, it is noted that the responsive ethics proposed could function as a permanent corrective. (shrink)

In the present note we give a direct deduction of the Axiom of Choice from the Maximal Ideal Theorem for commutative rings with unit.

It is shown for an arbitrary topos that the Law of the Excluded Middle holds in its propositional logic iff it satisfies the limited choice principle that every epimorphism from 2 = 1 ⊕ 1 splits.

Michael Dummett's approach to the metaphysical issue of realism through the philosophy of language, his challenge to realism, and his philosophy of language itself are central topics in contemporary analytic philosophy and have influenced the work of other major figures such as Quine, Putnam, and Davidson. This book offers an accessible and systematic presentation of the main elements of Dummett's philosophy. This book's overarching theme is Dummett's discussion of realism: his characterization of realism, his attack on realism, and his invention (...) and exploration of the anti-realist position. This book begins by examining Dummett's views on language. Only against that setting can one fully appreciate his conception of the realism issue. With this in place, Weiss returns to Dummett's views on the nature of meaning and understanding to unfold his challenge to realism. Weiss devotes the remainder of the book to examining the anti-realist position. He discusses anti-realist theories of meaning and then investigates anti-realism's revisionary consequences. Finally, he engages with Dummett's discussion of two difficult challenges for the anti-realist: the past and mathematics. (shrink)