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.

The quantum theory of ur-objects proposed by C. F. von Weizsäcker has to be interpreted as a quantum theory of information. Ur-objects, or urs, are thought to be the simplest objects in quantum theory. Thus an ur is represented by a twodimensional Hilbert space with the universal symmetry group SU (2), and can only be characterized as one bit of potential information. In this sense it is not a spatial but an information atom. The physical structure of the ur theory is reviewed, and the philosophical consequences of its interpretation as an information theory are demonstrated by means of some important concepts of physics such as time, space, entropy, energy, and matter, which in ur theory appear to be directly connected with information as "the" fundamental substance. This hopefully will help to provide a new understanding of the concept of information.

Researchers on the neural correlates of consciousness (NCC) need to distinguish mere statisticalNCCs from NCCs proper. Some neural events may be co-occurrent, probabilistically coupled,or coincidental with a type of conscious experience but lack any deeper connection to it, whilein other cases, the relation between neural states and a type of experience hints at a strongmetaphysical relation, which distinguishes such NCCs proper from mere statistical NCCs. In orderto address this issue of how to distinguish NCCs proper from mere statistical NCCs, we proposea position we call neurophenomenal structuralism. The position hinges on the uncontroversialidea that phenomenal experiences relate to each other in degrees of similarity and difference.These complex structures are used to identify and individuate experiences in the methods ofneuroscience, psychophysics, and phenomenology. Such individuation by structure leads to phenomenalholism, which has implications for how to investigate consciousness neuroscientificallyand generates a constraint by which we can distinguish NCCs proper from mere statistical NCCs:the structural similarity constraint. Neural activation must preserve the structure governing thedomain of experiences it is associated with in order to count as that domain’s NCC proper. Anyactivation that fails to preserve phenomenal structure fails to be an NCC proper. We illustratehow this constraint works with a study by Brouwer & Heeger (2009) as an example.

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 re-shuffling 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.