In a recent paper [Hellman, 2003], we examined to what extent category theory (“CT”) provides an autonomous framework for mathematical structuralism. The upshot of that investigation was that, as it stands, while CT provides many valuable insights into mathematical structure---specific structures and structure in general---, it does not sufficiently address certain key questions of logic and ontology that, in our view, any structuralist framework needs to address. On the positive side, however, a theory of large domains was sketched as (...) a way of supplying answers to those key questions, answers intended to be friendly to CT both in demonstrating its autonomy vis-à-vis set theory and in preserving its “arrows only” methods of describing and interrelating structures and the insights that those methods provide. The “large domains”, hypothesized as logicomathematical possibilities, are intended as suitably rich background universes of discourse relative to which both category-and-topos theory and set theory can be developed side by side, without either emerging as “prior to” the other. Although those domains, as described, resemble natural models of set theory (on an iterative conception) or toposes suitably enriched with an equivalent of the Replacement Axiom, they are defined without set-membership as a primitive, and also without ‘function’ or ‘category’ or ‘functor’ as primitives; all that is required is a combination of ‘part/whole’ and plural quantification (in effect, the resources of monadic second-order logic). This background.. (shrink)
As argued in Hellman (1993), the theorem of Pour-El and Richards (1983) can be seen by the classicist as limiting constructivist efforts to recover the mathematics for quantum mechanics. Although Bridges (1995) may be right that the constructivist would work with a different definition of closed operator, this does not affect my point that neither the classical unbounded operators standardly recognized in quantum mechanics nor their restrictions to constructive arguments are recognizable as objects by the constructivist. Constructive substitutes (...) that may still be possible necessarily involve additional incompleteness in the mathematical representation of quantum phenomena. Concerning a second line of reasoning in Hellman (1993), its import is that constructivist practice is consistent with a liberal stance but not with a radical, verificationist philosophical position. Whether such a position is actually espoused by certain leading constructivists, they are invited to clarify. (shrink)
Three principal varieties of mathematical structuralism are compared: set-theoretic structuralism (‘STS’) using model theory, Shapiro's ante rem structuralism invoking sui generis universals (‘SGS’), and the author's modal-structuralism (‘MS’) invoking logical possibility. Several problems affecting STS are discussed concerning, e.g., multiplicity of universes. SGS overcomes these; but it faces further problems of its own, concerning, e.g., the very intelligibility of purely structural objects and relations. MS, in contrast, overcomes or avoids both sets of problems. Finally, it is argued that the modality (...) of MS or a close cousin appears at crucial junctures in both STS and SGS, so that the above outcome is not obviously tendentious. (shrink)
Predicativity requirements of explicit presentability of objects and predicatively acceptable proof are distinguished from predicativist theses of a philosophical character. Familiar among these are expressions of skepticism about the objectivity of full power sets of infinite sets. Articulation of strong, limitative theses, however, turns out to be problematic: impredicative commitments creep into the very formulations, e.g. that “predicative definability'' marks a limit of “intelligibility''. A thought experiment is proposed to undermine the predicativist idea that arbitrary parts of an infinite whole (...) of atoms are “mind- or language-dependent''. On the other hand, weaker claims, e.g., that predicative mathematics is “more secure'' than impredicative, are nearly platitudinous. The interesting philosophical force of predicativism seems to be negative, in its challenge to indispensability arguments, à la Gödel-Friedman, for the transfinite in pure mathematics, and à la Quine-Putnam, for abstract mathematics in the sciences. Evidence is mounting in favor of Gödel-Friedman, e.g. impredicativity of free-variable formulations of theorems such as Kruskal's and Graph Minor, and more far-reaching, recent work in Boolean Relation Theory. This may lead to a realization of Gödel's idea of justifying strong axioms of infinity through their unifying, explanatory role, in analogy with theoretical physics. (shrink)
Category theory and topos theory have been seen as providing a structuralist framework for mathematics autonomous vis-a-vis set theory. It is argued here that these theories require a background logic of relations and substantive assumptions addressing mathematical existence of categories themselves. We propose a synthesis of Bell's many-topoi view and modal-structuralism. Surprisingly, a combination of mereology and plural quantification suffices to describe hypothetical large domains, recovering the Grothendieck method of universes. Both topos theory and set theory can be carried out (...) relative to such domains; puzzles about ‘large categories’ and ‘proper classes’ are handled in a uniform way, by relativization, sustaining insights of Zermelo. (shrink)
In a recent paper, while discussing the role of the notion of analyticity in Carnap’s thought, Howard Stein wrote: “The primitive view–surely that of Kant–was that whatever is trivial is obvious. We know that this is wrong; and I would put it that the nature of mathematical knowledge appears more deeply mysterious today than it ever did in earlier centuries – that one of the advances we have made in philosophy has been to come to an understanding of just ∗I (...) am grateful to audiences at the Steinfest, University of Chicago, May 21-23, 1999, and at the Philosophy of Mathematics Conference at the University of California, Santa Barbara, Feb. 4-6, 2000, and especially to Stewart Shapiro and Tony Anderson, for helpful comments on earlier drafts of this paper. (shrink)
Along with Frege, Russell maintained an absolutist stance regarding the subject matter of mathematics, revealed rather than imposed, or proposed, by logical analysis. The Fregean definition of cardinal number, for example, is viewed as (essentially) correct, not merely adequate for mathematics. And Dedekind’s “structuralist” views come in for criticism in the Principles. But, on reflection, Russell also flirted with views very close to a (different) version of structuralism. Main varieties of modern structuralism and their challenges are reviewed, taking account of (...) Russell’s insights. Problems of absolutism plague some versions, and, interestingly, Russell’s critique of Dedekind can be extended to one of them, ante rem structuralism. This leaves modal-structuralism and a category theoretic approach as remaining non-absolutist options. It is suggested that these should be combined. (shrink)
With the rise of multiple geometries in the nineteenth century, and in the last century the rise of abstract algebra, of the axiomatic method, the set-theoretic foundations of mathematics, and the influential work of the Bourbaki, certain views called “structuralist” have become commonplace. Mathematics is seen as the investigation, by more or less rigorous deductive means, of “abstract structures”, systems of objects fulfilling certain structural relations among themselves and in relation to other systems, without regard to the particular nature of (...) the objects themselves. Geometric spaces need not be made up of spatial or temporal points or other intrinsically geometric objects; as Hilbert famously put it, items of furniture suitably interrelated could satisfy all the relevant axiomatic conditions as far as pure mathematics is concerned. A group, for instance, can be any multiplicity of objects with operations fulfilling the basic requirements of the binary group operation; indeed the very abstractness of the group concept allows for its remarkably wide applicability in pure and applied mathematics. Similar remarks can be made regarding other algebraic structures, and the many spaces of analysis, differential geometry, topology, etc. Of course, mathematicians distinguish between “abstract structures” and “concrete ones”, e.g. made up of familiar, basic items such as real or complex numbers or functions of such, or rationals, or integers, etc. (For example, the space L2 of square-integrable functions from R (or Rn) to C, with inner product (f, g) =. (shrink)
A remarkable development in twentieth-century mathematics is smooth infinitesimal analysis (‘SIA’), introducing nilsquare and nilpotent infinitesimals, recovering the bulk of scientifically applicable classical analysis (‘CA’) without resort to the method of limits. Formally, however, unlike Robinsonian ‘nonstandard analysis’, SIA conflicts with CA, deriving, e.g., ‘not every quantity is either = 0 or not = 0.’ Internally, consistency is maintained by using intuitionistic logic (without the law of excluded middle). This paper examines problems of interpretation resulting from this ‘change of logic’, (...) arguing that standard arguments based on ‘smoothness’ requirements are question-begging. Instead, it is suggested that recent philosophical work on the logic of vagueness is relevant, especially in the context of a Hilbertian structuralist view of mathematical axioms (as implicitly defining structures of interest). The relevance of both topos models for SIA and modal-structuralism as appled to this theory is clarified, sustaining this remarkable instance of mathematical pluralism. (shrink)
After some metatheoretic preliminaries on questions of justification and rational reconstruction, we lay out some key desiderata for foundational frameworks for mathematics, some of which reflect recent discussions of pluralism and structuralism. Next we draw out some implications (pro and con) bearing on set theory and category and topos therory. Finally, we sketch a variant of a modal-structural core system, incorporating elements of predicativism and the systems of reverse mathematics, and consider how it fares with respect to the desiderata highlighted (...) earlier. Overall, we are making a case for "foundations with modest, welltempered foundationalism". (shrink)
Predicative mathematics in the sense originating with Poincar´ e and Weyl begins by taking the natural number system for granted, proceeding immediately to real analysis and related fields. On the other hand, from a logicist or set-theoretic standpoint, this appears problematic, for, as the story is usually told, impredicative principles seem to play an essential role in the foundations of arithmetic itself.1 It is the main purpose of this paper to show that this appearance is illusory: as will emerge, a (...) predicatively acceptable axiomatization of the natural number system can be formulated, and both the existence of structures of the relevant type and the categoricity of the relevant axioms can be proved in a predicatively acceptable way. (shrink)
Develops a structuralist understanding of mathematics, as an alternative to set- or type-theoretic foundations, that respects classical mathematical truth while ...
We develop a point-free construction of the classical one- dimensional continuum, with an interval structure based on mereology and either a weak set theory or logic of plural quantification. In some respects this realizes ideas going back to Aristotle,although, unlike Aristotle, we make free use of classical "actual infinity". Also, in contrast to intuitionistic, Bishop, and smooth infinitesimal analysis, we follow classical analysis in allowing partitioning of our "gunky line" into mutually exclusive and exhaustive disjoint parts, thereby demonstrating the independence (...) of "indecomposability" from a non-punctiform conception. It is surprising that such simple axioms as ours already imply the Archimedean property and that they determine an isomorphism with the Dedekind-Cantor structure of R as a complete, separable, ordered field. We also present some simple topological models of our system, establishing consistency relative to classical analysis. Finally, after describing how to nominalize our theory, we close with comparisons with earlier efforts related to our own. (shrink)
Despite my concerted efforts to formulate the linguistic doctrine of (first-order) logical truth, explicitly not as a claim that stipulations governing logical particles suffice to generate the logical truths (LD(I)), but as a determination thesis (LD(III))--that stipulations that certain particles behave as the classical logical particles suffice to determine uniquely the class of logically valid sentences, whose emptiness is clear and relatively unproblematic--, Quine2 nevertheless managed to read me as having claimed “that the logical truths can be generated (sic!) by (...) stipulations--hence conventions--without the regress”! This was all the more disheartening as Quine had also written, in earlier correspondence,3 concerning my answer to the regress argument of Quine’s “Truth by Convention”: “I think it a good answer.” That answer turned on the point that neither the conventionalist nor anyone else need justify the logical truths--as empty, they require no justification--but rather that logical rules are needed, and perfectly in order, to justify of any logical truth that indeed it requires no justification in virtue of membership in the privileged class. Evidently, Quine must have changed his mind about this, for he disparages my notion of a “stipulated universal trait”, such as ‘being red or not red’, by rhetorically asking: “But how, without prior logic, do we then infer, in particular, that the Taj Mahal has the trait?” (P. 206.) We agree that inferences cannot be made without logic, but why.. (shrink)
A plurality of approaches to foundational aspects of mathematics is a fact of life. Two loci of this are discussed here, the classicism/constructivism controversy over standards of proof, and the plurality of universes of discourse for mathematics arising in set theory and in category theory, whose problematic relationship is discussed. The first case illustrates the hypothesis that a sufficiently rich subject matter may require a multiplicity of approaches. The second case, while in some respects special to mathematics, raises issues of (...) ontological multiplicity and relativity encountered in the natural sciences as well. (shrink)
This paper explores the status of the von Neumann-Luders state transition rule (the "projection postulate") within "real-logic" quantum logic. The entire discussion proceeds from a reading of the Luders rule according to which, although idealized in applying only to "minimally disturbing" measurements, it nevertheless makes empirical claims and is not a purely mathematical theorem. An argument (due to Friedman and Putnam) is examined to the effect that QL has an explanatory advantage over Copenhagen and other interpretations which relativize truth-value assignments (...) to experimental arrangements. Two versions of QL, the lattice-theoretic (LT) and partial-Boolean-algebra (PBA), are considered. It turns out that the projection postulate is intimately connected with the choice of conditional connective for QL. The effect of the projection postulate is obtained with the Sasaki conditional. However, this choice is found to require extra assumptions, on both the LT and PBA versions, which are either just as ad hoc as the projection postulate itself or indefensible from within the real-logic QL framework. (shrink)
This paper explores strengths and limitations of both predicativism and nominalism, especially in connection with the problem of characterizing the continuum. Although the natural number structure can be recovered predicatively (despite appearances), no predicative system can characterize even the full predicative continuum which the classicist can recognize. It is shown, however, that the classical second-order theory of continua (third-order number theory) can be recovered nominalistically, by synthesizing mereology, plural quantification, and a modal-structured approach with essentially just the assumption that an (...) -sequence of concrete atoms be possible. Predicative flexible type theory may then be used to carry out virtually all of scientifically applicable mathematics in a natural way, still without ultimate need of the platonist ontology of classes and relations. (shrink)
Several leading topics outstanding after John Earman's Bayes or Bust? are investigated further, with emphasis on the relevance of Bayesian explication in epistemology of science, despite certain limitations. (1) Dutch Book arguments are reformulated so that their independence from utility and preference in epistemic contexts is evident. (2) The Bayesian analysis of the Quine-Duhem problem is pursued; the phenomenon of a "protective belt" of auxiliary statements around reasonably successful theories is explicated. (3) The Bayesian approach to understanding the superiority of (...) variety of evidence is pursued; a recent challenge (by Wayne) is converted into a positive result on behalf of the Bayesian analysis, potentially with far-reaching consequences. (4) The condition for applying the merger-of-opinion results and the thesis of underdetermination of theories are compared, revealing significant limitations in applicability of the former. (5) Implications concerning "diachronic Dutch Book" arguments and "non-Bayesian shifts" are drawn, highlighting the incompleteness, but not incorrectness, of Bayesian analysis. (shrink)
To what extent can constructive mathematics based on intuitionistc logic recover the mathematics needed for spacetime physics? Certain aspects of this important question are examined, both technical and philosophical. On the technical side, order, connectivity, and extremization properties of the continuum are reviewed, and attention is called to certain striking results concerning causal structure in General Relativity Theory, in particular the singularity theorems of Hawking and Penrose. As they stand, these results appear to elude constructivization. On the philosophical side, it (...) is argued that any mentalist-based radical constructivism suffers from a kind of neo-Kantian apriorism. It would be at best a lucky accident if objective spacetime structure mirrored mentalist mathematics. the latter would seem implicitly committed to a Leibnizian relationist view of spacetime, but is it doubtful if implementation of such a view would overcome the objection. As a result, an anti-realist view of physics seems forced on the radical constructivist. (shrink)
We list, with discussions, various principles of scientific realism, in order to exhibit their diversity and to emphasize certain serious problems of formulation. Ontological and epistemological principles are distinguished. Within the former category, some framed in semantic terms (truth, reference) serve their purpose vis-a-vis instrumentalism (Part 1). They fail, however, to distinguish the realist from a wide variety of (constructional) empiricists. Part 2 seeks purely ontological formulations, so devised that the empiricist cannot reconstruct them from within. The main task here (...) is to characterize "independence of mind". A pair of notions, "physical invariance" and "anti-determination", seem to work. They enable us to assess anew "the problem of constructing the physical out of the phenomenal" (yielding certain clarifications demanded by Goodman). Modern cosmology, especially, is seen to present insuperable obstacles to such empiricist approaches to science. The final section on epistemological principles reveals a morass better avoided in favor of an elementary claim about perception, together with a rejection of any absolute observation/theory dichotomy. Finally, a positive, realist notion of "observable-in-principle" is sketched, and it is suggested that, from the perspective of relativistic cosmology, even this defines no boundary to potential knowledge. (shrink)
In the …rst part of this paper, the origins of modal-structuralism are traced from Hilary Putnam’s seminal article, "Mathematics without Foundations" (1967) to its transformation and development into the author’s modal-structural approach. The addition of a logic of plurals is highlighted for its recovery (in combination with the resources of mereology) of full, second-order logic, essential for articulating a good theory of mathematical structures. The second part concentrates on the motivation of large trans…nite cardinal numbers, arising naturally from the second-order (...) machinery combined with an extendability principle on structures for set theories due independently to Zermelo (1930) and Putnam (in the paper just cited). The power of this is enhanced by a novel modal re‡ection principle recently introduced by the author. This is illustrated in detail with the …rst axiom of in…nity: After reviewing some of the trouble this basic classical axiom has caused for previous foundational programs, we show how it is derived easily using the re‡ection principle and a weak form of extendability for …nite structures. We conclude with some comparative remarks on how this improves on the closest set-theoretic analogue to the present proposal. (shrink)
Standard proofs of generalized Bell theorems, aiming to restrict stochastic, local hidden-variable theories for quantum correlation phenomena, employ as a locality condition the requirement of conditional stochastic independence. The connection between this and the no-superluminary-action requirement of the special theory of relativity has been a topic of controversy. In this paper, we introduce an alternative locality condition for stochastic theories, framed in terms of the models of such a theory (§2). It is a natural generalization of a light-cone determination condition (...) that is essentially equivalent to mathematical conditions that have been used to derive Bell inequalities in the deterministic case. Further, it is roughly equivalent to a condition proposed by Bell that, in one investigation, needed to be supplemented with a much stronger assumption in order to yield an inequality violated by some quantum mechanical predictions. It is shown here that this reflects a very general situation: from the proposed locality condition, even adding the strict anticorrelation condition and the auxiliary hypotheses needed to derive experimentally useful (and theoretically telling) inequalities, no Bell-type inequality is derivable. (These independence claims are the burden of §4.) A certain limitation on the scope of the proposed stochastic locality condition is exposed (§5), but it is found to be rather minor. The conclusion is thus supported that conditional stochastic independence, however reasonable on other grounds, is essentially stronger than what is required by the special theory.Our results stand in apparent contradiction with a class of derivations purporting to obtain generalized Bell inequalities from locality alone. It is shown in Appendix (B) that such proofs do not achieve their goal. This fits with our conclusion that generalized Bell theorems are not straightforward generalizations of theorems restricting deterministic hidden-variable theories, and that, in fact, such generalizations do not exist. This leaves open the possibility that a satisfactory, non-deterministic account of the quantum correlation phenomena can be given within the framework of the special theory. (shrink)
Structuralism is a view about the subject matter of mathematics according to which what matters are structural relationships in abstraction from the intrinsic nature of the related objects. Mathematics is seen as the free exploration of structural possibilities, primarily through creative concept formation, postulation, and deduction. The items making up any particular system exemplifying the structure in question are of no importance; all that matters is that they satisfy certain general conditions—typically spelled out in axioms defining the structure or structures (...) of interest—characteristic of the branch of mathematics in question. Thus, in the basic case of arithmetic, the famous “axioms” of Richard Dedekind (taken over by Giuseppe Peano, as he acknowledged) were conditions in a definition of a “simply infinite system”, with an initial item, each item having a unique next one, no two with the same next one, and all items finitely many steps from the initial one. (The latter condition is guaranteed by the axiom of mathematical induction.) All such systems are structurally identical, and, in a sense to be made more precise, the shared structure is what mathematics investigates. (In other cases, multiple structures are allowed, as in abstract algebra with its many groups, rings, fields, and so forth.) This structuralist view of arithmetic thus contrasts with the absolutist view, associated with Gottlob Frege and Bertrand Russell, that natural numbers must in fact be certain definite objects, namely classes of equinumerous concepts or classes. (shrink)
Quantum logic as genuine non-classical logic provides no solution to the "paradoxes" of quantum mechanics. From the minimal condition that synonyms be substitutable salva veritate, it follows that synonymous sentential connectives be alike in point of truth-functionality. It is a fact of pure mathematics that any assignment Φ of (0, 1) to the subspaces of Hilbert space (dim. ≥ 3) which guarantees truth-preservation of the ordering and truth-functionality of QL negation, violates truth-functionality of QL ∨ and $\wedge $ . Thus, (...) from within both the classical framework and that of any QL that preserves elementary set theory, two distinct (nonsynonymous) sets of connectives are discernible. Classical derivations of QM paradoxes are all available unless the language of QM is not classically closed. Maintaining this requires a strong and selfdefeating verification theory of meaning, the philosophical cornerstone of the Copenhagen interpretation to which QL was to provide an alternative. (shrink)
This paper presents parts of a theory of radical translation with applications to the problem of construing reference. First, in sections 1 to 4 the general standpoint, inspired by Goodman's approach to induction, is set forth. Codification of sound translational practice replaces the aim of behavioral reduction of semantic notions. The need for a theory of translational projection (manual construction on the basis of a finite empirical correlation of sentences) is established by showing the anomalies otherwise resulting (e.g. from Quine's (...) position). Then in section 5 a partial characterization of what constitutes an "admissible translation manual" is developed in the form of rules of translational projection governing correspondence of sentence-parts of a language-pair. Finally, in section 6, we give applications of the theory to the problem of construing reference. The general rules of section 5 suffice to rule out deviant referential schemes which have been held inscrutable alternatives to standard schemes. (shrink)
Standard presentations of axioms for set theory as truths simpliciter about actual-objects the sets-confront a number of puzzles associated with platonism and foundationalism. In his classic (1930), Zermelo suggested an alternative "many worlds" view. Independently, Putnam (1967) proposed something similar, explicitly incorporating modality. A modal-structural synthesis of these ideas is sketched in which obstacles to their formalization are overcome. Extendability principles are formulated and used to motivate many small largecardinals. The use of second-order logic as a coherent (...) and clear framework for set theory is supported. (shrink)
Two EPR arguments are reviewed, for their own sake, and for the purpose of clarifying the status of "stochastic" hidden variables. The first is a streamlined version of the EPR argument for the incompleteness of quantum mechanics. The role of an anti-instrumentalist ("realist") interpretation of certain probability statements is emphasized. The second traces out one horn of a central foundational dilemma, the collapse dilemma; complex modal reasoning, similar to the original EPR, is used to derive determinateness (of all spin components (...) of two spin- 1 / 2 particles in the singlet state) from just (a form of) weak locality, result definiteness, and an assumption on propensities based on conservation. Theories meeting these conditions are therefore constrained by the Bell inequalities. Neither controversial assumptions of "strong locality" ("factorability") nor of determinism are employed in the derivation. The categories of "stochastic hidden variables" are then analyzed; one can focus on "quasi-definite" theories, without loss of generality. A means of excluding these is proposed, based on a demand that certain ideal cases be accurately treated. Theorems from quantum measurement theory, sometimes cited as showing that such cases are not physically possible, are found inapplicable. (shrink)
After some introductory remarks on "experimental metaphysics", a brief survey of the current situation concerning the major types of hidden-variable theories and the inexistence proofs is presented. The category of stochastic, contextual, local theories remains open. Then the main features of a logical analysis of "locality" are sketched. In the deterministic case, a natural "light-cone determination" condition helps bridge the gap that has existed between the physical requirements of the special theory of relativity and formal conditions used in proving the (...)Bell-Wigner theorem. Natural generalization to the stochastic type, taking account of the distinction between epistemic and physical probabilities, leads to a series of independence claims constituting some (possibly) significant limitations on generalized Bell theorems. In particular, the conditional stochastic independence requirement is seen both to go beyond the demand of compliance with the STR and to be a genuine necessity (up to equivalence in this kind of strength) in deriving any Bell theorem for the stochastic case. The conclusion is also supported that, if determinism is given up, the Bell theorems and experiments do not pose an additional obstacle to unifying relativity theory and quantum mechanics beyond what is already posed by the "instantaneous" collapse of the wave function. (shrink)
Three questions are highlighted concerning the scope and force of indispensability arguments supporting classical, infinitistic mathematics. The first concerns the need for non-constructive reasoning for scientifically applicable mathematics; the second concerns the need for impredicative set existence principles for finitistic and scientifically applicable mathematics, respectively; and the third concerns the general status of such arguments in light of recent work in mathematical logic, especially that of Friedman et al. and Feferman et al. Some recent results (of Pour-El and Richards and (...) of the author) are then presented bearing on the first question on the need for non-constructive analysis, especially for quantum physics. Despite the impressive work of Bishop et al. in constructive analysis, Hilbert's objection to intuitionism still carries significant force, and may be decisive depending in part on one's conception of "physics". (shrink)
Recent technical developments in the logic of nominalism make it possible to improve and extend significantly the approach to mathematics developed in Mathematics without Numbers. After reviewing the intuitive ideas behind structuralism in general, the modal-structuralist approach as potentially class-free is contrasted broadly with other leading approaches. The machinery of nominalistic ordered pairing (Burgess-Hazen-Lewis) and plural quantification (Boolos) can then be utilized to extend the core systems of modal-structural arithmetic and analysis respectively to full, classical, polyadic third- and fourthorder number (...) theory. The mathenatics of many structures of central importance in functional analysis, measure theory, and topology can be recovered within essentially these frameworks. (shrink)
After briefly reviewing the standard set-theoretic resolutions of the Burali-Forti paradox, we examine how the paradox arises in set theory formalized with plural quantifiers. A significant choice emerges between the desirable unrestricted availability of ordinals to represent well-orderings and the sensibility of attempting to refer to ‘absolutely all ordinals’ or ‘absolutely all well-orderings’. This choice is obscured by standard set theories, which rely on type distinctions which are obliterated in the setting with plurals. Zermelo's attempt ( 1930 ) to secure (...) ordinal representability of arbitrary well-orderings through relativization of quantification to set-theoretic models is reviewed and found wanting. The natural modal-structural recasting provides, it is claimed, a good repair. (shrink)
Willful blindness is not an appropriate substitute for knowledge in crimes that require a mens rea of knowledge because an actor who contrives his own ignorance is only sometimes as culpable as a knowing actor. This paper begins with the assumption that the classic willfully blind actorâthe drug courierâis culpable. If so, any plausible account of willful blindness must provide criteria that find this actor culpable. This paper then offers two limiting cases: a criminal defense lawyer defending a client he (...) suspects of perjury and a pain doctor who suspects his patient may be lying about her pain. The paper argues that each of these actors is justified in cultivating ignorance about his clientâs or patientâs truthfulness. If this is right, then a good theory of willful blindness must distinguish these cases. The article argues that neither Husak & Callenderâs motivation-based account of willful blindness nor the recklessness account is able to do so. The paper proposes the following alternative: contrived ignorance constitutes culpable blindness when the decision to remain blind or to cultivate blindness is not itself justified. This Justification approach meshes with our intuitions about willfully blind drug couriers as well as willfully blind lawyers and doctors. (shrink)
This paper explores the American bankruptcy system -- especially the Chapter 11 code -- which since 1978 has allowed insolvent companies the opportunity to restructure and reorganise with the benefit of court protection from creditors. Particular attention is focused on asbestos companies, such as Johns--Manville, which have been among the most consistent and controversial filers for bankruptcy under Chapter 11. The history of asbestos and Chapter 11 is explored, against the backdrop of the burgeoning asbestos crisis, caused by increasing mortality (...) and litigation. Some of the business and ethical issues involved are highlighted by examining in detail a recent bankruptcy (Federal Mogul/T&N in 2001) that has implications in both Britain and America. Chapter 11 bankruptcy is evaluated, particularly in the light of the trend towards similar mechanisms of insolvency in the UK, Europe and the rest of the world. It is concluded that, certainly as regards the experience with asbestos, Chapter 11 offers an inefficient and inequitable method of rehabilitating or rescuing failing businesses. (shrink)
In his provocative article for this issue, GeoffreyHellman has astutely attacked the philosophical grounds for predicativity from several angles. Though I am not now nor never have been a predicativist, I have to admit to being a sympathizer since I am an avowed anti-platonist, at least insofar as set theory is concerned, and I grant the natural numbers a position of primacy in our mathematical thought. Philosophically, the predicative position may be characterized as the restriction to that (...) which is implicit in accepting the natural number structure. The subject has thus been of great interest to me and has periodically commanded much of my attention research-wise over the last forty years, especially as concerns its logical and mathematical potentialities. A caveat: a confirmed predicativist--if there be any such--would perhaps have stronger reasons than those marshalled here to defend the position on philosophical grounds. (shrink)
In recent times there have been a number of proposals for a nominalistic philosophy of mathematics. These proposals divide into two quite distinct camps: those who take mathematical propositions to be true, and those who take them to be untrue.2 Both options face substantial difficulties, but let’s focus on the first option. The problem here is in asserting that mathematical propositions such as ‘there exist infinitely many complex roots of the Riemann zeta function’ are true (as this one surely is) (...) and then to go on to deny that there are any complex numbers. To do this just seems inconsistent, or at least “intellectually dishonest” (Putnam, 1971, p. 347). One way to approach this problem is to reinterpret the mathematical claims in question so that they come out true, but do not refer to mathematical objects. So for example, GeoffreyHellman [1989] interprets mathematical claims to be about possible structures. Such options, since they do not take mathematical claims at face value, must employ a non-uniform semantics and this is thought, by almost everyone, to be a significant price to pay for one’s nominalism. The problem is particularly acute when one considers mixed mathematical and empirical statements such as ‘there exists a planet with mass m and location (x, y, z) and a function G that describes the gravitational potential of the planet at time t’. Here different parts of a single sentence must be treated differently—the talk of planets (and perhaps fields) is treated literally but the mathematical parts are treated non-literally. Apparently the only alternative to reinterpreting mathematical discourse is to follow Hartry Field [1980] and deny the truth of mathematical propositions. But this option is very counterintuitive. (shrink)
This note examines the mereological component of GeoffreyHellman's most recent version of modal structuralism. There are plausible forms of agnosticism that benefit only a little from Hellman's mereological turn.
We can learn from questions as well as from their answers. This paper urges some things to learn from questions about categorical foundations for mathematics raised by GeoffreyHellman and from ones he invokes from Solomon Feferman.
claims that constructive mathematics is inadequate for spacetime physics and hence that constructive mathematics cannot be considered as an alternative to classical mathematics. He also argues that the contructivist must be guilty of a form of a priorism unless she adopts a strong form of anti-realism for science. Here I want to dispute both claims. First, even if there are non-constructive results in physics this does not show that adequate constructive alternatives could not be formulated. Secondly, the constructivist adopts a (...) 'philosophy first' approach that Hellman rejects. This deep difference means that the viability of constructive mathematics cannot yet be decided by determining whether current scientific theories require classical mathematics. We need to decide which approach is most appropriate before we can even determine how we should go about deciding whether we should be constructive or classical mathematicians. (shrink)
In a recent paper, Michael Friedman and Hilary Putnam argued that the Luders rule is ad hoc from the point of view of the Copenhagen interpretation but that it receives a natural explanation within realist quantum logic as a probability conditionalization rule. GeoffreyHellman maintains that quantum logic cannot give a non-circular explanation of the rule, while Jeffrey Bub argues that the rule is not ad hoc within the Copenhagen interpretation. As I see it, all four are wrong. (...) Given that there is to be a projection postulate, there are at least two natural arguments which the Copenhagen advocate can offer on behalf of the Luders rule, contrary to Friedman and Putnam. However, the argument which Bub offers is not a good one. At the same time, contrary to Hellman, quantum logic really does provide an explanation of the Luders rule, and one which is superior to that of the Copenhagen account, since it provides an understanding of why there should be a projection postulate at all. (shrink)
In Karl Marx's Theory of History: A Defence (1978), G. A. Cohen has developed a distinctively functionalist interpretation of historical materialism. In this paper I outline Cohen's novel reconstruction of Marx and subject it to two independent internal criticisms. I first argue that explanations cannot conform to Cohen's functionalist model. I then suggest that even if there could be explanations having the structure he has proposed, they would fail to be helpful in illuminating the causal kernel of Marx's theory. Finally (...) I sketch a neglected but more promising approach to clarifying historical materialism, due to GeoffreyHellman. (shrink)
The English Surgeon . 2008. Produced and directed by Geoffrey Smith. Eyeline Films and Bungalow Town Productions. English and Ukrainian, with English subtitles. 1 hour 33 minutes. http://www.theenglishsurgeon.com Content Type Journal Article DOI 10.1007/s11673-010-9225-7 Authors Rebecca L. Volpe, California Pacific Medical Center Clinical Ethics Fellow, Program in Medicine & Human Values 2395 Sacramento Street, 3rd floor San Francisco CA 94115 USA Journal Journal of Bioethical Inquiry Online ISSN 1872-4353 Print ISSN 1176-7529 Journal Volume Volume 7 Journal Issue Volume 7, (...) Number 2. (shrink)
In this article I discuss Geoffrey Vickers’ ideas from the perspective of moral and political philosophy. His thought is presented through three key terms, which I suggest can encapsulate his philosophy: (i) our human capacity to respond aptly to our situation; (ii) the analysis of modern society in terms of institutions; and (iii) the moral importance of responsibility to the maintenance of human culture and cooperation.
It is argued that Hellman's arguments purporting to demonstrate that constructive mathematics cannot cope with unbounded operators on a Hilbert space are seriously flawed, and that there is no evidence that his thesis is correct.
Geoffrey of Monmouth's Historia Regum Britanniae (c.1136) had an enormous impact on the young Milton, so much so that in his Latin poem Mansus he imagined re-writing it as an English national epic. The fact that he could identify with the Britons against the Saxons in this imagined poem has been taken by many to prove the instability or alterity of his Early Modern national identity. In demonstrating how early in its reception Geoffrey's history had become ?Englished,? that (...) is, how early it had come to articulate the matter of Britain as England writ large, I hope to indicate that even in his earliest works?especially the Maske at Ludlow Castle, Mansus, and Epitaphium Damonis? the Londoner Milton is not so much diffident about or unrecognizable in his understanding of national identity as party, however inadvertently, to a process of relentless Anglicization. And in this I hope not to refute but to suggest the limits of contemporary Archipelagic criticism. (shrink)
Against Hellman's (1997) recent claims, I argue that Bayesianism is unable to explain the value of generally successful aspects of scientific methodology, viz., deflecting blame from well-confirmed theories onto auxiliaries and preferring more-varied data. Such an explanation would require not just objectification of priors, but a reason to believe priors will generally fall on values that justify the practice. Given the track record on the objectification problem, adding further conditions on priors merely makes the Bayesian's problems even worse.
Defending Poetry studies the tradition of poetic defence, or apologia, as it has been pursued and developed by three of the twentieth century's leading poet-critics: Joseph Brodsky, Seamus Heaney, and Geoffrey Hill. It begins with an extended introduction to philosophical debates over the ethical value of literature from Plato to Levinas and continues by situating these three poets as in one sense historically continuous with the defences of Horace, Sidney, Coleridge, and Shelley, but also as drastically other. This otherness (...) is bounded on one side by the example of T. S. Eliot's career-long contemplation of the ideal of poetic 'integrity', and on the other by a collective recognition of the twentieth century's great horrors, which seem to corrode all associations of art and the good. Through close readings of the poems and prose essays of Brodsky, Heaney, and Hill, Defending Poetry makes a timely intervention in current debates about literature's ethics, arguing that any ethics of literature ought to take into account not only poetry, but also the writings of poets on the value of poetry. (shrink)
