Results for 'Philip Welch'

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  1. Reflecting on Absolute Infinity.Philip Welch & Leon Horsten - 2016 - Journal of Philosophy 113 (2):89-111.
    This article is concerned with reflection principles in the context of Cantor’s conception of the set-theoretic universe. We argue that within such a conception reflection principles can be formulated that confer intrinsic plausibility to strong axioms of infinity.
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  2.  15
    Closed and unbounded classes and the härtig quantifier model.Philip D. Welch - 2022 - Journal of Symbolic Logic 87 (2):564-584.
    We show that assuming modest large cardinals, there is a definable class of ordinals, closed and unbounded beneath every uncountable cardinal, so that for any closed and unbounded subclasses $P, Q, {\langle L[P],\in,P \rangle }$ and ${\langle L[Q],\in,Q \rangle }$ possess the same reals, satisfy the Generalised Continuum Hypothesis, and moreover are elementarily equivalent. Examples of such P are Card, the class of uncountable cardinals, I the uniform indiscernibles, or for any n the class $C^{n}{=_{{\operatorname {df}}}}\{ \lambda \, | \, (...)
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  3. Proving Theorems from Reflection.Philip Welch - 2019 - In Deniz Sarikaya, Deborah Kant & Stefania Centrone (eds.), Reflections on the Foundations of Mathematics. Springer Verlag.
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  4.  12
    Proving Theorems from Reflection.Philip Welch - 2019 - In Stefania Centrone, Deborah Kant & Deniz Sarikaya (eds.), Reflections on the Foundations of Mathematics: Univalent Foundations, Set Theory and General Thoughts. Springer Verlag. pp. 79-97.
    We review some fundamental questions concerning the real line of mathematical analysis, which, like the Continuum Hypothesis, are also independent of the axioms of set theory, but are of a less ‘problematic’ nature, as they can be solved by adopting the right axiomatic framework. We contend that any foundations for mathematics should be able to simply formulate such questions as well as to raise at least the theoretical hope for their resolution.The usual procedure in set theory is to add so-called (...)
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  5.  25
    Some observations on truth hierarchies: A correction.Philip D. Welch - 2020 - Review of Symbolic Logic 13 (4):857-860.
    A correction is needed to our paper: to the definition contained within the statement of Lemma 1.5 and thus arguments around it in §3.
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  6.  32
    On the possibility, or otherwise, of hypercomputation.Philip D. Welch - 2004 - British Journal for the Philosophy of Science 55 (4):739-746.
    We claim that a recent article of P. Cotogno ([2003]) in this journal is based on an incorrect argument concerning the non-computability of diagonal functions. The point is that whilst diagonal functions are not computable by any function of the class over which they diagonalise, there is no ?logical incomputability? in their being computed over a wider class. Hence this ?logical incomputability? regrettably cannot be used in his argument that no hypercomputation can compute the Halting problem. This seems to lead (...)
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  7.  14
    Comparing Inductive and Circular Definitions: Parameters, Complexity and Games.Philip Welch, Kai–Uwe Kühnberger, Benedikt Löwe & Michael Möllerfeld - 2005 - Studia Logica 81 (1):79-98.
    Gupta-Belnap-style circular definitions use all real numbers as possible starting points of revision sequences. In that sense they are boldface definitions. We discuss lightface versions of circular definitions and boldface versions of inductive definitions.
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  8.  75
    Set-theoretic absoluteness and the revision theory of truth.Benedikt Löwe & Philip D. Welch - 2001 - Studia Logica 68 (1):21-41.
    We describe the solution of the Limit Rule Problem of Revision Theory and discuss the philosophical consequences of the fact that the truth set of Revision Theory is a complete 1/2 set.
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  9.  18
    Discrete transfinite computation models.Philip D. Welch - 2011 - In S. B. Cooper & Andrea Sorbi (eds.), Computability in Context: Computation and Logic in the Real World. World Scientific. pp. 375--414.
  10.  21
    Recognizable sets and Woodin cardinals: computation beyond the constructible universe.Merlin Carl, Philipp Schlicht & Philip Welch - 2018 - Annals of Pure and Applied Logic 169 (4):312-332.
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  11. Possible-worlds semantics for modal notions conceived as predicates.Volker Halbach, Hannes Leitgeb & Philip Welch - 2003 - Journal of Philosophical Logic 32 (2):179-223.
    If □ is conceived as an operator, i.e., an expression that gives applied to a formula another formula, the expressive power of the language is severely restricted when compared to a language where □ is conceived as a predicate, i.e., an expression that yields a formula if it is applied to a term. This consideration favours the predicate approach. The predicate view, however, is threatened mainly by two problems: Some obvious predicate systems are inconsistent, and possible-worlds semantics for predicates of (...)
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  12.  26
    Godel's Disjunction: The Scope and Limits of Mathematical Knowledge.Leon Horsten & Philip Welch (eds.) - 2016 - Oxford, England: Oxford University Press UK.
    The logician Kurt Godel in 1951 established a disjunctive thesis about the scope and limits of mathematical knowledge: either the mathematical mind is equivalent to a Turing machine (i.e., a computer), or there are absolutely undecidable mathematical problems. In the second half of the twentieth century, attempts have been made to arrive at a stronger conclusion. In particular, arguments have been produced by the philosopher J.R. Lucas and by the physicist and mathematician Roger Penrose that intend to show that the (...)
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  13.  82
    On the Consistency Strength of the Inner Model Hypothesis.Sy-David Friedman, Philip Welch & W. Hugh Woodin - 2008 - Journal of Symbolic Logic 73 (2):391 - 400.
  14.  28
    Assessed Danger-to-Others as a Reason for Psychiatric Hospitalization: An Investigation of Patients' Perspectives.Philip Welches & Michael Pica - 2005 - Journal of Phenomenological Psychology 36 (1):45-74.
    This study investigated subjective experiences of nine men who had been psychiatrically hospitalized upon being assessed as "dangerous-to-others-due-to-a-mental-illness." Using a phenomenological interviewing approach, researchers helped subjects construct narratives of their pre-hospitalization experiences. The research illuminated aspects of life-contexts that were shared among all or nearly all subjects: feeling ostracized and alone; struggling with longstanding and pervasive feelings of inadequacy; experiencing a sense or a fear of having little or no control or options in life; and feeling emotionally depressed, misunderstood, and (...)
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  15.  34
    Comparing incomparable Kleene degrees.Philip Welch - 1985 - Journal of Symbolic Logic 50 (1):55-58.
  16.  13
    Minimality in the ▵13-degrees.Philip Welch - 1987 - Journal of Symbolic Logic 52 (4):908 - 915.
    We show in ZFC, assuming all reals have sharps, that a countable collection of ▵ 1 3 -degrees without a minimal upper bound implies the existence of inner models with measurable cardinals.
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  17.  2
    Minimality in the $triangle^1_3$-Degrees.Philip Welch - 1987 - Journal of Symbolic Logic 52 (4):908-915.
    We show in ZFC, assuming all reals have sharps, that a countable collection of $\triangle^1_3$-degrees without a minimal upper bound implies the existence of inner models with measurable cardinals.
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  18.  1
    Minimality in the Δ⅓-degrees.Philip Welch - 1987 - Journal of Symbolic Logic 52 (4):908-915.
  19. Set-Theoretic Absoluteness and the Revision Theory.Philip Welch - 2003 - Bulletin of Symbolic Logic 9 (2):235-237.
  20.  8
    Stably measurable cardinals.Philip D. Welch - 2021 - Journal of Symbolic Logic 86 (2):448-470.
    We define a weak iterability notion that is sufficient for a number of arguments concerning $\Sigma _{1}$ -definability at uncountable regular cardinals. In particular we give its exact consistency strength first in terms of the second uniform indiscernible for bounded subsets of $\kappa $ : $u_2$, and secondly to give the consistency strength of a property of Lücke’s.TheoremThe following are equiconsistent:There exists $\kappa $ which is stably measurable;for some cardinal $\kappa $, $u_2=\sigma $ ;The $\boldsymbol {\Sigma }_{1}$ -club property holds (...)
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  21.  32
    The natural hierarchy and quasi-hierarchy of constructibility degrees.Philip Welch - 1986 - Journal of Symbolic Logic 51 (1):130-134.
    We investigate the set S 2 of "quickly sharped" reals: \begin{align*}S_2 &= \{x \mid x \in M, M \text{the} <^\ast-\text{least mouse} \not\in L\lbrack x\rbrack\} \\ &= \{x \mid L\lbrack x\rbrack \models "V = K"\},\\ \end{align*} in the manner of [K] defining a natural hierarchy and quasi-hierarchy of constructibility degrees and identifying their termination points.
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  22.  9
    The ramified analytical hierarchy using extended logics.Philip D. Welch - 2018 - Bulletin of Symbolic Logic 24 (3):306-318.
    The use of Extended Logics to replace ordinary second order definability in Kleene’s Ramified Analytical Hierarchy is investigated. This mirrors a similar investigation of Kennedy, Magidor and Väänänen [11] where Gödel’s universe L of constructible sets is subjected to similar variance. Enhancing second order definability allows models to be defined which may or may not coincide with the original Kleene hierarchy in domain. Extending the logic with game quantifiers, and assuming strong axioms of infinity, we obtain minimal correct models of (...)
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  23.  27
    The reals in core models.Philip Welch - 1987 - Journal of Symbolic Logic 52 (1):64-67.
    We set $\mathscr{D} = \langle\mathscr{D}, \leq_L, \tt\#\rangle$ , where D is the set of degrees of nonconstructibility for countable sets of countable ordinals. We show how to define inductively over this structure the degrees of such sets of ordinals in K, the core model, and the next few core models thereafter, i.e. without reference to mice, premice or measurable cardinals.
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  24.  15
    Games and Ramsey-like cardinals.Dan Saattrup Nielsen & Philip Welch - 2019 - Journal of Symbolic Logic 84 (1):408-437.
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  25. The Undecidability of Propositional Adaptive Logic.Leon Horsten & Philip Welch - 2007 - Synthese 158 (1):41-60.
    We investigate and classify the notion of final derivability of two basic inconsistency-adaptive logics. Specifically, the maximal complexity of the set of final consequences of decidable sets of premises formulated in the language of propositional logic is described. Our results show that taking the consequences of a decidable propositional theory is a complicated operation. The set of final consequences according to either the Reliability Calculus or the Minimal Abnormality Calculus of a decidable propositional premise set is in general undecidable, and (...)
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  26.  17
    Decision Times of Infinite Computations.Merlin Carl, Philipp Schlicht & Philip Welch - 2022 - Notre Dame Journal of Formal Logic 63 (2).
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  27. Field on revenge.Agustin Rayo & Philip Welch - 2007 - In J. C. Beall (ed.), Revenge of the Liar: New Essays on the Paradox. Oxford University Press.
  28.  37
    Bounded Martin's maximum, weak Erdős cardinals, and $\psi\sb {AC}$.David Asperó & Philip Welch - 2002 - Journal of Symbolic Logic 67 (3):1141-1152.
  29.  22
    The undecidability of propositional adaptive logic.Leon Horsten & Philip Welch - 2009 - Synthese 169 (1):217-218.
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  30.  26
    Bounded Martin's Maximum, Weak [image] Cardinals, and [image].David Asperó & Philip D. Welch - 2002 - Journal of Symbolic Logic 67 (3):1141 - 1152.
    We prove that a form of the $Erd\H{o}s$ property (consistent with $V = L\lbrack H_{\omega_2}\rbrack$ and strictly weaker than the Weak Chang's Conjecture at ω1), together with Bounded Martin's Maximum implies that Woodin's principle $\psi_{AC}$ holds, and therefore 2ℵ0 = ℵ2. We also prove that $\psi_{AC}$ implies that every function $f: \omega_1 \rightarrow \omega_1$ is bounded by some canonical function on a club and use this to produce a model of the Bounded Semiproper Forcing Axiom in which Bounded Martin's Maximum (...)
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  31.  6
    When cardinals determine the power set: inner models and Härtig quantifier logic.Jouko Väänänen & Philip D. Welch - forthcoming - Mathematical Logic Quarterly.
    We show that the predicate “x is the power set of y” is ‐definable, if V = L[E] is an extender model constructed from a coherent sequences of extenders, provided that there is no inner model with a Woodin cardinal. Here is a predicate true of just the infinite cardinals. From this we conclude: the validities of second order logic are reducible to, the set of validities of the Härtig quantifier logic. Further we show that if no L[E] model has (...)
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  32.  15
    Local club condensation and l-likeness.Peter Holy, Philip Welch & Liuzhen Wu - 2015 - Journal of Symbolic Logic 80 (4):1361-1378.
  33.  24
    Erratum: The Undecidability of Propositional Adaptive Logic.Leon Horsten & Philip Welch - 2009 - Synthese 169 (1):217 - 218.
  34.  18
    Global square and mutual stationarity at the ℵn.Peter Koepke & Philip D. Welch - 2011 - Annals of Pure and Applied Logic 162 (10):787-806.
    We give the proof of a theorem of Jensen and Zeman on the existence of a global □ sequence in the Core Model below a measurable cardinal κ of Mitchell order ) equal to κ++, and use it to prove the following theorem on mutual stationarity at n.Let ω1 denote the first uncountable cardinal of V and set to be the class of ordinals of cofinality ω1.TheoremIf every sequence n m. In particular, there is such a model in which for (...)
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  35.  18
    Menachem Magidor. Representing sets of ordinals as countable unions of sets in the core model. Transactions of the American Mathematical Society, vol. 317 , pp. 91–126. [REVIEW]Philip Welch - 1995 - Journal of Symbolic Logic 60 (2):701-704.
  36.  5
    Review: Menachem Magidor, Representing Sets of Ordinals as Countable Unions of Sets in the Core Model. [REVIEW]Philip Welch - 1995 - Journal of Symbolic Logic 60 (2):701-704.
  37.  14
    Review: Sy D. Friedman, Strong Coding; Sy D. Friedman, A Guide to "Strong Coding.". [REVIEW]Philip Welch - 1990 - Journal of Symbolic Logic 55 (3):1311-1313.
  38.  4
    Sy D. Friedman. Strong coding. Annals of pure and applied logic, vol. 35, pp. 1–98. - Sy D. Friedman. A guide to “Strong coding.”Annals of pure and applied logic, vol. 35, pp. 99–122. [REVIEW]Philip Welch - 1990 - Journal of Symbolic Logic 55 (3):1311-1313.
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  39.  10
    Bounded Martin's Maximum, weak Erdӧs cardinals, and ψ Ac.David Asperó & Philip D. Welch - 2002 - Journal of Symbolic Logic 67 (3):1141-1152.
  40. Revision Revisited.Leon Horsten, Graham E. Leigh, Hannes Leitgeb & Philip Welch - 2012 - Review of Symbolic Logic 5 (4):642-664.
    This article explores ways in which the Revision Theory of Truth can be expressed in the object language. In particular, we investigate the extent to which semantic deficiency, stable truth, and nearly stable truth can be so expressed, and we study different axiomatic systems for the Revision Theory of Truth.
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  41.  52
    Comparing inductive and circular definitions: Parameters, complexity and games.Kai-Uwe Küdhnberger, Benedikt Löwe, Michael Möllerfeld & Philip Welch - 2005 - Studia Logica 81 (1):79 - 98.
    Gupta-Belnap-style circular definitions use all real numbers as possible starting points of revision sequences. In that sense they are boldface definitions. We discuss lightface versions of circular definitions and boldface versions of inductive definitions.
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  42.  7
    Asymmetric Cut and Choose Games.Christopher Henney-Turner, Peter Holy, Philipp Schlicht & Philip Welch - forthcoming - Bulletin of Symbolic Logic:1-31.
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  43.  3
    Sprache und Kritische Theorie.Philip Hogh & Stefan Deines (eds.) - 2016 - Frankfurt: Campus Verlag.
    Welche Rolle spielt Sprache für eine kritische Theorie? Die Beiträger beantworten diese Frage vor dem Hintergrund gegenwärtiger Diskussionen in der Sprach- und Sozialphilosophie. Sie zeichnen so ein Bild epistemologischer, kommunikativer, sozialer und normativer Gefahren und Potenziale der Sprache. Mit Beiträgen von Robert B. Brandom, Alexander G. Düttmann, Martin Seel u.a.
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  44.  17
    Diogenis Laertii Vitae Philosophorum (review).Philip Merlan - 1965 - Journal of the History of Philosophy 3 (1):119-121.
    In lieu of an abstract, here is a brief excerpt of the content:BOOK REVIEWS 119 Der Verf. bedient sieh in Verfolgung seines Ziels der fibliehen historischen Methode, die er mit Meistersehaft handhabt. Doch ist er keineswegs ein typischer Vertreter des modernen Historismus. Als Philosoph ist er gefesselt von den Problemen, die sich in der dreifachen Thematik seiner Untersuehung verbergen. Er begibt sich in die Gesehichte, aber doch nur, um yon Zeit zu Zeit aus ihr herauszutreten und i)berlegungen nachzugehen, die er (...)
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  45.  9
    Advance Care Planning (ACP) als Element eines klinisch-ethischen Unterstützungsangebotes – Darstellung und Evaluation.Andre Nowak, Kim Philip Linoh, Lilit Flöther, Jan Schildmann & Stephan Nadolny - 2023 - Ethik in der Medizin 35 (4):469-486.
    Zusammenfassung Hintergrund Advance Care Planning (ACP) wird auch in Deutschland zunehmend praktiziert. Aus klinisch-ethischer Perspektive bietet ACP eine Möglichkeit, Vorausverfügungen zu konkretisieren und auf diese Weise die Entscheidungsfindung bei fehlender Selbstbestimmungsfähigkeit von Patient:innen zu unterstützen. Während es für Gesprächsangebote im Sinne des ACP in Pflegeeinrichtungen und Einrichtungen der Eingliederungshilfe seit 2015 Finanzierungsmöglichkeiten gibt und erste Studien zu Angeboten veröffentlich wurden, fehlt es in Deutschland bisher an publizierten Evaluationsstudien zu ACP-Angeboten im Krankenhaus. Intervention und Methoden Im vorliegenden Beitrag erfolgt die strukturierte (...)
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  46.  30
    Benedikt Löwe and Philip Welch. Set-theoretic absoluteness and the revision theory. Studia Logica, vol. 68 , pp. 21–41. - Benedikt Löwe. Revision sequences and computers with an infinite amount of time. Journal of Logic and Computation, vol. 11 , pp. 25–40. [REVIEW]Volker Halbach - 2003 - Bulletin of Symbolic Logic 9 (2):235-237.
  47.  22
    How Exactly Does Panpsychism Help Explain Consciousness?Philip Goff - 2024 - Journal of Consciousness Studies 31 (3):56-82.
    There has recently been a revival of interest in panpsychism as a theory of consciousness. The hope of the contemporary proponents of panpsychism is that the view enables us to integrate consciousness into our overall theory of reality in a way that avoids the deep difficulties that plague the more conventional options of physicalism on the one hand and dualism on the other. However, panpsychism comes in two forms — strong and weak emergentist — and there are arguments that seem (...)
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  48.  31
    The state.Philip Pettit - 2023 - Princeton: Princeton University Press.
    In this work, the prominent political philosopher Philip Pettit embarks on a massive undertaking to offers major new accounts of the foundations of the state and the nature of justice. In doing so Pettit builds a new theory of what the state is and what it ought to be, addresses the normative question of how justice serves as a measure of the success of a state, and the way it should operate in relation to its citizens and other people.
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  49.  8
    Gratuitous risk: danger and recklessness perception of adventure sports participants.Philip A. Ebert, Ian Durbach & Claire Field - forthcoming - Journal of the Philosophy of Sport:1-18.
    Since the 1970’s there has been a major increase in adventure sports participation but it seems that engagement in such sports comes with a stigma: adventure sports participants are often regarded as reckless ‘daredevils’. We approach the questions about people’s perception of risk and recklessness in adventure sports by combining empirical research with philosophical analysis. First, we provide empirical evidence that suggests that laypeople tend to assess the danger of adventure sports as greater than more mundane sports and judge adventure (...)
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  50. Voluntary Belief on a Reasonable Basis.Philip J. Nickel - 2010 - Philosophy and Phenomenological Research 81 (2):312-334.
    A person presented with adequate but not conclusive evidence for a proposition is in a position voluntarily to acquire a belief in that proposition, or to suspend judgment about it. The availability of doxastic options in such cases grounds a moderate form of doxastic voluntarism not based on practical motives, and therefore distinct from pragmatism. In such cases, belief-acquisition or suspension of judgment meets standard conditions on willing: it can express stable character traits of the agent, it can be responsive (...)
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