Holger Lyre

The aim of this paper is to scrutinize active externalism and its repercussions for externalism about mental content. I start from the claim that active externalism is a version of content externalism that follows from the extended cognition thesis as a thesis about cognitive vehicles. Various features of active content externalism are explored by comparison with the known forms of passive externalism – in particular with respect to the multiple realizability of the relevant external content-determining components and with respect to mental causation. A crucial result is that social externalism is already a version of active externalism. I conclude with a first sketch of a general account of meaning inspired by extended cognition: a use theory supplemented by a functional-role account.

Recent developments under the keywords dynamicism, embodiment and situated cognition suggest the view that cognitive systems are not confined to the neural sys‐tem but leak into the world beyond the traditional system boundaries. This is the thesis of extended cognition. Such an extension of the cognitive vehicles leads to a new kind of content externalism, known as active externalism. The essay pursues three objectives: firstly, to distinguish the theses of extended cognitive and active externalism. Secondly, to delineate active externalism from its various passive-externalist precursors in the form of physical, historical and social externalism and to scrutinize its special position, which amounts to a comprehensive discussion and analysis of all variants of mental externalism. And thirdly, to show that social externalism as opposed to physical and historical externalism allows for a gradual transition from passive to active mental externalism.

Gegenstand dieses Beitrags ist eine Auseinandersetzung mit der Wissenschaftlichkeit der Medizin. Den Leitfaden der Analyse bildet dabei ein jüngerer Ansatz in der analytischen Wissenschaftstheorie, wonach Systematizität als zentrales Kriterium von Wissenschaft anzusehen ist (Hoyningen-Huene 2013). Ich werde im Detail zeigen, dass die Medizin dieses mehrdimensionale Kriterium insgesamt erfüllt, dass aus der Wissenschaftlichkeit der Medizin aber gleichwohl normative Konsequenzen folgen, die beispielsweise zur Abgrenzung von der Homöopathie und einer kritischen Bewertung des biopsychosozialen Modells führen. Zudem resultieren der Anwendungscharakter der Medizin und die zentrale Bedeutung des Arzt-Patienten-Verhältnisses nicht in einer Schwächung des Anspruchs der Medizin als Wissenschaft.

Der Aufsatz lotet den zeitgenössischen Reduktionismus aus. Im ersten Teil wird in zentrale Stationen der wissenschaftstheoretischen Debatte um Theorien-Reduktion eingeleitet, wobei das Schaffner-Hooker-Modell und die Bedeutung von Näherungsbegriffen hervorgehoben werden. Der zweite Teil behandelt die multiple Realisierbarkeit als eines der nach wie vor zentralen anti-reduktionistischen Argumente. Die Analyse soll zeigen, dass es sich hierbei nicht um ein einheitliches Phänomen handelt, sondern dass sehr verschiedene Kategorien von Multirealisierbarkeit zu unterscheiden sind. In einem vereinfachten Slogan: multiple Realisierbarkeit ist ihrerseits multirealisiert. Der Aufsatz entwickelt eine rohe Taxonomie von Typen multipler Realisierbarkeit und möglicher reduktionistischer Strategien, wobei genuine Fälle von Multirealisierbarkeit auf geteilte Eigenschaften zurückgeführt werden. Im letzten Teil wird die besondere Rolle von Näherungen im Zusammenhang mit der explanatorischen Spannung zwischen ontischem Reduktionismus und epistemischen Anti-Reduktionismus verdeutlicht.

Im ersten Abschnitt illustrierte ich die These der erweiterten Kognition und diskutiere einige mögliche Missverständnisse. Im zweiten Abschnitt werde ich vier Domänen kognitiver Erweiterung auseinanderhalten, nämlich eine Erweiterung in die körperliche, physikalische, 'informatorische' und soziale Umgebung betreffend. Um die These der erweiterten Kognition vor dem Einwand der kognitiven Inflation zu schützen, muss man für jeden dieser Bereiche (und gegebenenfalls noch spezieller) spezifische Bedingungen und Mechanismen der kognitiven Kopplung an die externen Komponenten angeben. Im dritten Abschnitt unterscheide ich die These der erweiterten Kognition, von der sich im ersten Abschnitt bereits zeigen wird, dass sie eine These kognitiver Vehikel ist, von einer externalistischen Gehaltsthese. Letztere bezeichne ich im Anklang an Clark und Chalmers als aktiven Externalismus und illustriere dessen Unterschiede und Besonderheiten gegenüber den bekannten 'passiven' Formen des semantischen oder mentalen Externalismus in der Philosophie des Geistes, die sich mit den Namen Putnam, Millikan und Burge verbinden. Im vierten Abschnitt verfolge ich die spezifische Idee, die Mechanismen geteilter Intentionalität als Kopplungsmechanismen kognitiver Erweiterung in die soziale Umgebung, speziell soziale Interaktionspartner, anzusehen. Dazu mache ich in einigem Detail von Bratmans bekannter Plan-Konzeption geteilter Intentionalität Gebrauch. Anhand der Ergebnisse dieser Analyse wird sich im fünften und letzten Abschnitt zeigen, in welchem Sinne es sich dabei im Keim bereits um einen sozialen Externalismus handelt. Der soziale Externalismus, so der Clou, stellt bereits eine verkappte Variante eines aktiven Externalismus dar.

Multiple Realizability (MR) must still be regarded as one of the principal arguments against type reductionist accounts of higher-order properties and their special laws. Against this I argue that there is no unique MR but rather a multitude of MR categories. In a slogan: MR is itself “multi-realized”. If this is true then we cannot expect one unique reductionist strategy against MR as an anti-reductionist argument. The main task is rather to develop a taxonomy of the wide variety of MR cases and to sketch possible reductionist answers for each class of cases. The paper outlines some first steps in this direction.

The paper presents and discusses the “which-is-which content of handedness,” the meaning of left as left and right as right, as a possible candidate for the idea of a genuine embodied cognitive content. After showing that the Ozma barrier, the non-transferability of the meaning of left and right, provides a kind of proof of the non-descriptive, indexical nature of the which-is-which content of handedness, arguments are presented which suggest that the classical representationalist account of cognition faces a perplexing problem of underdetermination of reference of left and right in the which-is-which sense. By way of contrast, no such problems occur in a framework were embodied contents are not mediated by some extra body model which carries the representational power, but are instead directly represented.

Structural Realism (SR) is typically rated as a moderate realist doctrine about the ultimate entities of nature described by fundamental physics. Whether it must be extended to the higher-level special sciences is not so clear. In this short paper I argue that there is no need to ‘structuralize’ the special sciences. By mounting concrete examples I show that structural descriptions and structural laws certainly play a role in the special sciences, but that they don’t play any exclusive role nor that they give us any reason to believe that all that there is on the various levels is structure. I fortify my points by arguing that structures are global entities (in order for SR not to collapse into a bundle ontology) and that the assumption of higher-level structures as genuinely global or holistic entities is even more arcane.

In der modernen Physik spielen Symmetrien eine herausragende Rolle zur Identifikation und Klassifizierung der fundamentalen Theorien und Entitäten. Symmetrien dienen der Darstellung invarianter Strukturen, das geeignete mathematische Werkzeug hierfür ist die Gruppentheorie. Eine Struktur lässt sich als eine Menge von Relationen verstehen, die einer Menge von Objekten aufgeprägt sind. Strukturell charakterisierte Objekte sind daher wesentlich über ihre relationalen Eigenschaften charakterisiert. Sieht man die theoretischen Entitäten wissenschaftlicher Theorien vornehmlich in dieser strukturellen Weise an, vertritt man eine moderate Variante eines wissenschaftlichen Realismus, die als Strukturenrealismus bekannt ist. Im Umfeld dieser drei Konzepte – Symmetrien, Strukturen, Realismus – bewegt sich der folgende Aufsatz.

Structural realism is sometimes said to undermine the theory underdetermination (TUD) argument against realism, since, in usual TUD scenarios, the supposed underdetermination concerns the object-like theoretical content but not the structural content. The paper explores the possibility of structural TUD by considering some special cases from modern physics, but also questions the validity of the TUD argument itself. The upshot is that cases of structural TUD cannot be excluded, but that TUD is perhaps not such a terribly serious anti-realistic argument

After decades of neglect philosophers of physics have discovered gauge theories--arguably the paradigm of modern field physics--as a genuine topic for foundational and philosophical research. Incidentally, in the last couple of years interest from the philosophy of physics in structural realism--in the eyes of its proponents the best suited realist position towards modern physics--has also raised. This paper tries to connect both topics and aims to show that structural realism gains further credence from an ontological analysis of gauge theories--in particular U(1) gauge theory. In the first part of the paper the framework of fiber bundle gauge theories is briefly presented and the interpretation of local gauge symmetry will be examined. In the second part, an ontological underdetermination of gauge theories is carved out by considering the various kinds of non-locality involved in such typical effects as the Aharonov-Bohm effect. The analysis shows that the peculiar form of non-separability figuring in gauge theories is a variant of spatiotemporal holism and can be distinguished from quantum theoretic holism. In the last part of the paper the arguments for a gauge theoretic support of structural realism are laid out and discussed.

Quantum theory is a tremendously successful physical theory, but nevertheless suffers from two serious problems: the measurement problem and the problem of interpretational underdetermination. The latter, however, is largely overlooked as a genuine problem of its own. Both problems concern the doctrine of realism, but pull, quite curiously, into opposite directions. The measurement problem can be captured such that due to scientific realism about quantum theory common sense anti-realism follows, while theory underdetermination usually counts as an argument against scientific realism. I will also consider the more refined distinctions of ontic and epistemic realism and demonstrate that quantum theory in its most viable interpretations conflicts with at least one of the various realism claims. A way out of the conundrum is to come to the bold conclusion that quantum theory is, possibly, wrong (in the realist sense).

Four empirically equivalent versions of general relativity, namely standard GR, Lorentz-invariant gravitational theory,and the gravitational gauge theories of the Lorentz and translation groups, are investigated in the form of a case study for theory underdetermination. The various ontological indeterminacies (both underdetermination and inscrutability of reference) inherent in gravitational theories are analyzed in a detailed comparative study. The concept of practical underdetermination is proposed, followed by a discussion of its adequacy to describe scientific progress.

This paper explores the argument structure of the concept of spontaneous symmetry breaking in the electroweak gauge theory of the Standard Model: the so-called Higgs mechanism. As commonly understood, the Higgs argument is designed to introduce the masses of the gauge bosons by a spontaneous breaking of the gauge symmetry of an additional field, the Higgs field. The technical derivation of the Higgs mechanism, however, consists in a mere reshuffling of degrees of freedom by transforming the Higgs Lagrangian in a gauge-invariant manner. This already raises serious doubts about the adequacy of the entire manoeuvre. It will be shown that no straightforward ontic interpretation of the Higgs mechanism is tenable, since gauge transformations possess no real instantiations. In addition, the explanatory value of the Higgs argument will be critically examined.

The aim of this paper is twofold: First, to present an examination of the principles underlying gauge field theories. I shall argue that there are two principles directly connected to the two well-known theorems of Emmy Noether concerning global and local symmetries of the free matter-field Lagrangian, in the following referred to as "conservation principle" and "gauge principle". Since both these express nothing but certain symmetry features of the free field theory, they are not sufficient to derive a true interaction coupling to a new gauge field. For this purpose it is necessary to advocate a third, truly empirical principle which may be understood as a generalization of the equivalence principle. The second task of the paper is to deal with the ontological question concerning the reality status of gauge potentials in the light of the proposed logical structure of gauge theories. A nonlocal interpretation of topological effects in gauge theories and, thus, the non-reality of gauge potentials in accordance with the generalized equivalence principle will be favoured.

The paper deals with an attempt to present an “abductive-transcendental” argument in favour of a particular version of structural realism (SR), dubbed Intermediate SR. In the first part of the paper the general structure of transcendental arguments is scrutinized with a close view on Kant’s original version and the prospect of their abductive variation. Then the role of symmetries in modern physics, especially symmetries without real instantiations and in particular gauge symmetries is discussed. This is combined with a presentation of SR as a promising current version of scientific realism. The discussion is supported by various arguments form gauge theories in modern physics. Intermediate SR, a realist position about all and only structurally derivable entities located between the extremes of Epistemic and Ontic SR turns out as the best fit to our current fundamental gauge physics and this finally leads to an abductive-transcendental reasoning concerning this position.

I give a response to Adrian Wüthrich’s critical review of my analysis of the Higgs mechanism, in which I try to clarify some possible misunderstandings. I concede that, as Wüthrich points out, many physicists see the Higgs mechanism as the roll-over from a symmetrical potential in the initial Lagrangian to a symmetry-breaking potential, while my former analysis had basically focused on the gauge-invariant transformation of the initial Lagrangian into the intended form. My main contention, however, still is that neither Higgs story has (as yet) much explanatory power

The goal of the paper is to develop and propose a general model of the state space of AI. Given the breathtaking progress in AI research and technologies in recent years, such conceptual work is of substantial theoretical interest. The present AI hype is mainly driven by the triumph of deep learning neural networks. As the distinguishing feature of such networks is the ability to self-learn, self-learning is identified as one important dimension of the AI state space. Another dimension is recognized as generalization, the possibility to go over from specific to more general types of problems. A third dimension is semantic grounding. Our overall analysis connects to a number of known foundational issues in the philosophy of mind and cognition: the blockhead objection, the Turing test, the symbol grounding problem, the Chinese room argument, and use theories of meaning. It shall finally be argued that the dimension of grounding decomposes into three sub-dimensions. And the dimension of self-learning turns out as only one of a whole range of “self-x-capacities” (based on ideas of organic computing) that span the self-x-subspace of the full AI state space.

The paper has three parts. In the first part ExtOSR, an extended version of Ontic Structural Realism, will be introduced. ExtOSR considers structural properties as ontological primitives, where structural properties are understood as comprising both relational and structurally derived intrinsic properties or structure invariants. It is argued that ExtOSR is best suited to accommodate gauge symmetry invariants and zero value properties. In the second part, ExtOSR will be given a Humean shape by considering structures as categorical and global. It will be laid out how such structures serve to reconstruct non-essential structural kinds and laws. In the third part Humean structural realism will be defended against the threat of quidditism.