We have previously established that [Formula: see text]-comprehension is equivalent to the statement that every dilator has a well-founded Bachmann–Howard fixed point, over [Formula: see text]. In this paper, we show that the base theory can be lowered to [Formula: see text]. We also show that the minimal Bachmann–Howard fixed point of a dilator [Formula: see text] can be represented by a notation system [Formula: see text], which is computable relative to [Formula: see text]. The statement that [Formula: see text] (...) is well founded for any dilator [Formula: see text] will still be equivalent to [Formula: see text]-comprehension. Thus, the latter is split into the computable transformation [Formula: see text] and a statement about the preservation of well-foundedness, over a system of computable mathematics. (shrink)

In previous work, the author has shown that $\Pi ^1_1$ -induction along $\mathbb N$ is equivalent to a suitable formalization of the statement that every normal function on the ordinals has a fixed point. More precisely, this was proved for a representation of normal functions in terms of Girard’s dilators, which are particularly uniform transformations of well orders. The present paper works on the next type level and considers uniform transformations of dilators, which are called 2-ptykes. We show that $\Pi (...) ^1_2$ -induction along $\mathbb N$ is equivalent to the existence of fixed points for all 2-ptykes that satisfy a certain normality condition. Beyond this specific result, the paper paves the way for the analysis of further $\Pi ^1_4$ -statements in terms of well ordering principles. (shrink)

Michael Rathjen and the present author have shown that ‐bar induction is equivalent to (a suitable formalization of) the statement that every normal function has a derivative, provably in. In this note we show that the base theory can be weakened to. Our argument makes crucial use of a normal function f with and. We shall also exhibit a normal function g with and.

Let Con↾x denote the finite consistency statement “there are no proofs of contradiction in T with ≤x symbols.” For a large class of natural theories T, Pudlák has shown that the lengths of the shortest proofs of Con↾n in the theory T itself are bounded by a polynomial in n. At the same time he conjectures that T does not have polynomial proofs of the finite consistency statements Con)↾n. In contrast, we show that Peano arithmetic has polynomial proofs of Con)↾n, (...) where Con∗ is the slow consistency statement for Peano arithmetic, introduced by S.-D. Friedman, Rathjen, and Weiermann. We also obtain a new proof of the result that the usual consistency statement Con is equivalent to ε0 iterations of slow consistency. Our argument is proof-theoretic, whereas previous investigations of slow consistency relied on nonstandard models of arithmetic. (shrink)

In the context of reverse mathematics, effective transfinite recursion refers to a principle that allows us to construct sequences of sets by recursion along arbitrary well orders, provided that each set is ‐definable relative to the previous stages of the recursion. It is known that this principle is provable in. In the present note, we argue that a common formulation of effective transfinite recursion is too restrictive. We then propose a more liberal formulation, which appears very natural and is still (...) provable in. (shrink)

In a recent paper by M. Rathjen and the present author it has been shown that the statement “every normal function has a derivative” is equivalent to $\Pi ^1_1$ -bar induction. The equivalence was proved over $\mathbf {ACA_0}$, for a suitable representation of normal functions in terms of dilators. In the present paper, we show that the statement “every normal function has at least one fixed point” is equivalent to $\Pi ^1_1$ -induction along the natural numbers.

We show that arithmetical transfinite recursion is equivalent to a suitable formalization of the following: For every ordinal \alpha there exists an ordinal /beta such that 1 + \beta \cdot (\beta + \alpha) admits an almost order preserving collapse into \beta. Arithmetical comprehension is equivalent to a statement of the same form, with \beta \cdot \alpha at the place of \beta \cdot (\beta + \alpha). We will also characterise the principles that any set is contained in a countable coded ω-model (...) of arithmetical transfinite recursion and arithmetical comprehension, respectively. (shrink)

We present a new manifestation of Gödel’s second incompleteness theorem and discuss its foundational significance, in particular with respect to Hilbert’s program. Specifically, we consider a proper extension of Peano arithmetic ( $\mathbf {PA}$ ) by a mathematically meaningful axiom scheme that consists of $\Sigma ^0_2$ -sentences. These sentences assert that each computably enumerable ( $\Sigma ^0_1$ -definable without parameters) property of finite binary trees has a finite basis. Since this fact entails the existence of polynomial time algorithms, it is (...) relevant for computer science. On a technical level, our axiom scheme is a variant of an independence result due to Harvey Friedman. At the same time, the meta-mathematical properties of our axiom scheme distinguish it from most known independence results: Due to its logical complexity, our axiom scheme does not add computational strength. The only known method to establish its independence relies on Gödel’s second incompleteness theorem. In contrast, Gödel’s theorem is not needed for typical examples of $\Pi ^0_2$ -independence (such as the Paris–Harrington principle), since computational strength provides an extensional invariant on the level of $\Pi ^0_2$ -sentences. (shrink)

Schmerl and Beklemishev’s work on iterated reflection achieves two aims: it introduces the important notion of \-ordinal, characterizing the \-theorems of a theory in terms of transfinite iterations of consistency; and it provides an innovative calculus to compute the \-ordinals for a range of theories. The present note demonstrates that these achievements are independent: we read off \-ordinals from a Schütte-style ordinal analysis via infinite proofs, in a direct and transparent way.

It is generally accepted that H. Friedman’s gap condition is closely related to iterated collapsing functions from ordinal analysis. But what precisely is the connection? We offer the following answer: In a previous paper we have shown that the gap condition arises from an iterative construction on transformations of partial orders. Here we show that the parallel construction for linear orders yields familiar collapsing functions. The iteration step in the linear case is an instance of a general construction that we (...) call ‘Bachmann–Howard derivative’. In the present paper, we focus on the unary case, i.e., on the gap condition for sequences rather than trees and, correspondingly, on addition-free ordinal notation systems. This is partly for convenience, but it also allows us to clarify a phenomenon that is specific to the unary setting: As shown by van der Meeren, Rathjen and Weiermann, the gap condition on sequences admits two linearizations with rather different properties. We will see that these correspond to different recursive constructions of sequences. (shrink)

The notion of countable well order admits an alternative definition in terms of embeddings between initial segments. We use the framework of reverse mathematics to investigate the logical strength of this definition and its connection with Fraïssé’s conjecture, which has been proved by Laver. We also fill a small gap in Shore’s proof that Fraïssé’s conjecture implies arithmetic transfinite recursion over $\mathbf {RCA}_0$, by giving a new proof of $\Sigma ^0_2$ -induction.

This paper explores the perversion of reality in the context of advanced technologies, such as AI, VR, and AR, through the lens of Jean Baudrillard’s theory of hyperreality and the precession of simulacra. By examining the transformative effects of these technologies on our perception of reality, with a particular focus on the usage of digital avatars, the paper highlights the blurred distinction between the real and the simulated, where the copy becomes more ‘real’ than the original. Drawing on Baudrillard’s concept (...) of hyperreality, the paper delves into the perversion of reality as individuals seek refuge in virtual pleasure paradises and embrace artificial pleasures through their digital avatars, disconnecting from genuine human experiences. The convergence of AI, VR, and AR technologies amplifies this hyperreal condition, where digital avatars mimic or surpass the depth of human relationships, challenging our understanding of what is real. In line with Baudrillard’s theory, the paper explores the objectification and commodification of reality within digital spaces, specifically examining the digital avatars’ role in the erosion of genuine human connections. It explores the implications of these avatars in terms of consent, exploitation, and loss of authenticity, echoing Baudrillard’s concerns about the distortion of reality in contemporary society. Recognizing the implications of these technologies, the paper calls for a critical reflection on their transformative power. It emphasizes the need for a nuanced understanding of the hyperreal condition and ethical responsibility in engaging with AI, VR, and AR, particularly in relation to the usage of digital avatars. By resisting the seductive allure of digital escapism and preserving genuine human connections, we can navigate the perversion of reality and cultivate empathy, compassion, and meaningful interactions that transcend the simulated experiences offered by technology. (shrink)

Lange Zeit hat die Idee eines musikalischen Fortschritts gleichermassen fasziniert und polarisiert. Als zentraler Bestandteil der Diskurse um die Neue Musik verlangt sie nach einer differenzierten historischen Betrachtung. Anhand von reichhaltigem Textmaterial analysiert Julia Freund die zentralen Konzepte und Argumentationslinien und entwirft ein vielfältiges Panorama der Debatten der 1950er Jahre. Ausgangspunkt ist ein close reading der Schriften und Vorlesungen Theodor W. Adornos, dessen Fortschrittsbegriff im Rahmen seines philosophischen Projekts der Aufklärungskritik greifbar wird. In einem zweiten und dritten Schritt nimmt (...) die Autorin die Denkfiguren und Narrative der seriellen Komponisten (darunter K. Stockhausen und P. Boulez) sowie die Gegenentwürfe ihrer Kritiker (wie P. Hindemith oder Fr. Blume) in den Blick"--Back cover. (shrink)

This collection of ten essays elucidates some of the more challenging aspects of Anscombe’s work and affirms her reputation as one of our most original ...

This paper takes a stand on Hamblin semantics and its relation to the semantics-to-pragmatics interface. Biased questions, where the speaker finds one of the options more likely and expects the confirmation that p is true, raise a concern about the limits of Hamblin semantics. I argue that biased questions have modified Hamblin semantics, while unbiased questions have unconstrained Hamblin semantics. The optional bias feature explains compositionally. It is triggered by likelihood presuppositions ranging Hamblin sets and highlighting the preferred alternative(s). Biased (...) effects are exceptionally possible in alternative and wh-questions, but only in polar questions, they can be encoded lexically and grammatically. I argue that Hamblin semantics covers all core types of questions, while some of its applications for non-questions are problematic. (shrink)

This paper investigates the responses of GPT-4, a state-of-the-art AI language model, to ten prominent philosophical paradoxes, and evaluates its capacity to reason and make decisions in complex and uncertain situations. In addition to analyzing GPT-4's solutions to the paradoxes, this paper assesses the model's Theory of Mind (ToM) capabilities by testing its understanding of mental states, intentions, and beliefs in scenarios ranging from classic ToM tests to complex, real-world simulations. Through these tests, we gain insight into AI's potential for (...) social reasoning and its capacity for more sophisticated forms of human-AI interaction. The paper also explores the limitations and biases of AI-generated reasoning and its implications for our comprehension of complex philosophical problems. (shrink)

We develop a set-theoretic semantics for Cocchiarella's second-order logical system . Such a semantics is a modification of the nonstandard sort of second-order semantics described, firstly, by Simms and later extended by Cocchiarella. We formulate a new second order logical system and prove its relative consistency. We call such a system and construct its set-theoretic semantics. Finally, we prove completeness theorems for proper normal extensions of the two systems with respect to certain notions of validity provided by the semantics.

"À son décès, Julien Freund laissait parmi ses papiers un recueil de textes inédits, sous forme épistolaire, adressés à ses amis et collègues : les Lettres de la vallée. Dans ces méditations, rédigées en sa retraite vosgienne - qui n'est pas sans évoquer la Hütte de Heidegger, de l'autre côté du Rhin - et loin des servitudes propres aux écrits universitaires, l'auteur de L'Essence du politique s'exprime en toute liberté, à bâtons rompus, sur ses sujets de prédilection (le politique, (...) l'idéologie, la guerre, les totalitarismes, l'utopie, la décadence), mais également l'enseignement, le journalisme, la connaissance, le droit, la morale, la métaphysique, les limites... Ce livre forme la clef de voûte où se rejoignent les grands thèmes de sa pensée."--Page 4 de la couverture. (shrink)

Anscombe holds that a proper account of intentional action must exhibit “a ‘form’ of description of events.” But what does that mean? To answer this question, I compare the method of Anscombe’s Intention with that of Frege’s Foundations of Arithmetic—another classic work of analytic philosophy that consciously opposes itself to psychological explanations. On the one hand, positively, I aim to identify and elucidate the kind of account of intentional action that Anscombe attempts to provide. On the other hand, negatively, I (...) hope to dispel the canard that Anscombe’s opposition to the causal theory of action is a product of “behaviorism.”. (shrink)

In den Aufsätzen dieses Bandes präsentiert Anton Friedrich Koch Hegels theoretische Philosophie als diejenige Nichtstandard-Metaphysik, in der sich die Metaphysik, nicht aber die Philosophie vollendet. Jenseits von Hegels Evolutionstheorie des Absoluten gilt es von einem Standpunkt der Endlichkeit aus neu zu philosophieren.

Der junge Heidegger hat die Welt begeistert und das Denken revolutioniert, indem er die lebendige Existenz des Menschen in den Mittelpunkt gestellt und dem Denken eine ungeheure Macht zugeschrieben hat: Das Denken stiftet die wahre Existenz der Menschheit und kann ihre Entfremdung aufheben. Sich selber hat er als Herold der Zeitenwende gesehen, der die abendländische Seinsvergessenheit durchbricht. Um sein Leben ranken sich ein Gewirr von Legenden, Schutzbehauptungen, Halbwahrheiten und Ganzlügen. Seine enthusiastische Parteinahme für den Nationalsozialismus und sein grotesk gescheiterter Versuch, (...) die deutsche Universität ins Neue Reich zu führen, lösen noch heute erregte Debatten aus. Wie ist aus dem konventionellen autoritätshörigen Priesterkandidaten über Nacht ein radikaler Philosoph geworden? Und wie aus diesem Kritiker philosophischer Elfenbeintürme der Guru einer Seinsreligion, der die Gegenwart grundsätzlich in Frage stellt? Warum verliebt sich der Vertreter eines unhinterfragten Antisemitismus ausgerechnet in eine jüdische Studentin? Fischers Charakterstudie fragt nach dem Zusammenhang von Leben und Werk. Sie ist die bisher umfassendste Biographie Heideggers, die auch der Politik die nötige Aufmerksamkeit schenkt. (shrink)

Foucault’s twofold attack on the modem concept of power gives us something to think about. Backed by ingenious historical analyses he devises an idea of systemic and productive power, abstracted from the conceptual connections between power and individual power-sources, viz. power and restrictions of freedom. The article probes Foucault’s historical sketches on. these two tasks. It defends the less radical view of power as constraining interests and freedom.

Since Hobbes' Leviathan was published in 1651, the 'problem of order' has been known for some time. Despite this long gestation period for social theory even today we do not have a universally agreed upon answer to this 'problem'. One of the reasons behind this lacuna may be the overly dispersed work being done in the economic and sociological traditions. Whereas one tradition favours 'collective action' as a central answer, the other thinks of the problem itself being dissolved by the (...) acceptance of 'socialized man'. Here, an attempt is made to offer the phenomenon of 'cooperation' as a promising middle ground for both traditions. To underline the importance of cooperation as an elementary social activity, first, cooperation is shown as working in tandem with its rival 'competition'. Secondly, several conceptual analyses of what is included in collective action and cooperation are offered. These analyses, thirdly, are deepened by an overview of the motivational bases potentially advancing cooperation. Overall, an awareness of the self-creating character of cooperation is explored, and put forward as the most feasible way of answering the classical problem of order. (shrink)

In contrast to the theories of relativity, quantum mechanics is not yet based on a generally accepted conceptual foundation. It is proposed here that the missing principle may be identified through the observation that all knowledge in physics has to be expressed in propositions and that therefore the most elementary system represents the truth value of one proposition, i.e., it carries just one bit of information. Therefore an elementary system can only give a definite result in one specific measurement. The (...) irreducible randomness in other measurements is then a necessary consequence. For composite systems entanglement results if all possible information is exhausted in specifying joint properties of the constituents. (shrink)

We discuss the difference between formal and natural languages, and argue that should the language metaphor have any foundation, it’s analogy with natural languages that should be taken into account. We discuss how such operation like reading, writing, sign, interpretation, etc., can be applied in the realm of the living and what can be gained, by such an approach, in order to understand the phenomenon of life.

This paper introduces and discusses three models of future: a determinist model, a stochastic model, and the model of True Prophetic Knowledge. All three models coexist in natural languages and are represented both in their grammatical systems and in the text-building discourse strategies speakers and authors apply to.

De l'apathie de l'âme humaine, ou, L'incapacité de l'âme de se sentir, et l'absence de faculté de sentir en elle, alors que notre oragnisme vivant possède ces qualités -- Sur les idées distinctes des choses qui appartiennent soit à notre âme, soit à notre corps organique vivant -- Traité de l'art de philosopher avec simplicité et précision.

This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be (...) preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant. (shrink)

I discuss the foundations of predicate ontologies based on two model notions – elementary states of affairs and eventualities, i.e. ordered pairs of initial and end states of affairs. Vendlerian classifications are oriented towards elementary states and tense logic, while Davidsonian classifications deal with eventualities and event logic. There are two kinds of atemporal predicates - fact and properties. Facts are propositional arguments of second-order predicates which add a special meaning that the embedded proposition was verified. Properties are atemporal first-order (...) predicates that lack eventive interpretation and are not associated with factive frames. Davidsonian states are homogeneous durable spatiotemporal things distinct both from atemporal properties and spatiotemporal dynamic predicates. Davidsonian states are causally independent, while resultatives are causally determined as they reconstruct a preceding event that has caused the end state p. I discuss the contrast between external and internal Davidsonian states. The former lack a priority argument and can be quantified extensionally. The latter have a priority experiential argument and can only be quantified intensionally. External states can be observed, while internal states cannot. (shrink)

Ernst Fehr’s experimental research on altruistic behaviour aims at superseding the classical homo oeconomicus in micro-economic behaviour theory. This essay discusses Fehr’s results from two points of view: first, in regard to the understanding of social action associated with the term “altruism”; second, in regard to the ‘anthropological’ strategy of research that is based on the laboratory method. Against the emphasis on altruism it will be argued that it misleads into providing a distorted description of social acting, and that, due (...) to insufficient clarity about motives for acting, Fehr’s empirical results give evidence not of altruism but rather of phenomena of social recognition. The objection against the anthropological strategy will be that it makes visible only local phenomena within prevailing social conditions and that it thus assumes more than it explains. (shrink)