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). (shrink)

In the following paper, I review and critically assess the four standard routes commonly taken to establish that gravitational waves possess energy-momentum: the increase in kinetic energy a GW confers on a ring of test particles, Bondi/Feynman’s Sticky Bead Argument of a GW heating up a detector, nonlinearities within perturbation theory, taken to reflect the fact that gravity contributes to its own source, and the Noether Theorems, linking symmetries and conserved quantities. Each argument is found to either to presuppose controversial (...) assumptions or to be outright spurious. I finally examine the standard interpretation of binary systems, according to which orbital decay is explained in terms of the system’s energy being via GW energy- momentum transport. I contend that a better interpretation, drawing only on the general-relativistic Equations of Motions and the Einstein Equations, is available - and in fact preferable; thereby also an inference to the best explanation for the vindication of GW energy-momentum is blocked. (shrink)

An Objectivity Principle (O) and a Locality Principle (L) are considered with respect to two simple, but fundamental Gedanken experiments, namely a “Welcher-Weg” Gedanken experiment and an Einstein-Podolsky-Rosen (EPR) Gedanken experiment. It is shown that, if both principles (O) and (L) are assumed to be valid, a contradiction, in the EPR case Bell’s inequality, can be derived implying that at least one of the two principles (O) and (L) has to be denied. It is shown that, if (O) is denied, (...) (L) is preserved in the EPR-Gedanken experiment. For a more adequate discussion, in particular of (L), the two experiments are described in Minkowskian space-time of special relativity. (shrink)

Summary The question underlying this article is whether the Kantian transcendental philosophy is wide enough to constitute the objects of quantum physics as objects of possible experience and consequently to found the objectivity of quantum physical knowledge. It is shown that the Kantian determinations of the categories (quality, substance, causality) can be interpreted and elaborated in such a way that the quantum physical concept of an object characterized by nonobjectivity of properties is conceived. Therefore the categories are valid in quantum (...) mechanics and warrant the objectivity of quantum physical experience. By the interpretation of the Kantian infinite judgement as an indefinite proposition it is possible to define the non-objectivity of properties categorially as indefiniteness of qualities. In particular by the indefiniteness of the position-quality the non-permanent localizability of quantum mechanical objects can be understood a priori. However the object of possible experience, especially the quantum mechanical object is underdetermined by the categories of substance and causality: If the object is determined to be a substance it is not yet conceived to be an individual; its characterization by means of probability laws is categorially indeterminate. In so far the significance of transcendental philosophy for the foundation of quantum physics is limited. (shrink)

Inspite of the great success in many disciplines the program of reductionism has failed its genuine purpose. Systemtheory however has yielded a new concept of reductionism which we call reductionism by correspondence and which may imply a new understanding of the mind-body problem. The crucial operations of reductionism by correspondence are called idealization, interpretation and classification. They are used to optimize the description of a system. Nevertheless they lead to certain deficiencies which cannot be avoided in principle. We are therefore (...) driven to the assumption that natural systems can only be described as probabilistic systems. From this point of view nothing is said about the direction of the reduction. (shrink)

Inspite of the great success in many disciplines the program of reductionism has failed its genuine purpose. Systemtheory however has yielded a new concept of reductionism which we call reductionism by correspondence and which may imply a new understanding of the mind-body problem. The crucial operations of reductionism by correspondence are called idealization, interpretation and classification. They are used to optimize the description of a system. Nevertheless they lead to certain deficiencies which cannot be avoided in principle. We are therefore (...) driven to the assumption that natural systems can only be described as probabilistic systems. From this point of view nothing is said about the direction of the reduction. (shrink)

This article examines Cohen’s “transcendental method”, Windelband’s “critical method”, the neo-Kantian distinctions between natural science and the humanities (i. e., human or cultural sciences), and Weber’s account of ideal-typical explanations. The Marburg and the Southwest Schools of neo-Kantianism have in common that their respective philosophies of science focused on method, but they substantially differ in their approaches. Cohen advanced the “transcendental method”, which was taken up and transformed by Natorp and Cassirer; later, it became influential in neo-Kantian approaches to 20th (...) century physics. Windelband distinguished between facts and values, linking the former to the “genetic” method of history and the latter to the “critical” method of philosophy; and between the “nomothetic” and “idiographic” methods of the empirical sciences, a distinction further elaborated by Rickert. The distinction does not give rise to a sharp discrimination but is rather what Weber would later call an ideal type. All these approaches contribute in different ways to understanding the structure of scientific knowledge, focusing on different aspects of the general path of the empirical sciences between rationalism and empiricism. (shrink)

The article investigates the way in which Peter Mittelstaedt has been contributing to the philosophy of physics for half a century. It is shown that he pursues a path between rationalism and empiricism in the sense of Erhard Scheibe’s philosophy of the physicists. Starting from Kant’s a priori he gives a rational reconstruction of the conceptual revolutions of 20th century physics. The central topic of his philosophy of physics is the quest for semantic self-consistency, which for quantum mechanics is a (...) hard nut to crack. (shrink)

The hypotheses of weak and strong objectification of quantum mechanical observables, as well as theoretical arguments and experimental evidence against these hypotheses, are systematically reviewed.

Quantum-mechanical event descriptions are context-dependent descriptions. The role of quantum (nondistributive) logic is in the partial ordering of contexts rather than in the ordering of quantum-mechanical events. Moreover, the kind of quantum logic displayed by quantum mechanics can be easily inferred from the general notion of contextuality used in ordinary language. The formalizable core of Bohr's notion of complementarity is the type of context dependence discussed in this paper.

I argue that quantum theory can, and in fact must, be applied to the Universe as a whole. After a general introduction, I discuss two concepts that are essential for my chain of arguments: the universality of quantum theory and the emergence of classical behaviors by decoherence. A further motivation is given by the open problem of quantum gravity. I then present the main ingredients of quantum cosmology and discuss their relevance for the interpretation of quantum theory. I end with (...) some brief epistemological remarks. (shrink)

Starting with the Born interpretation of quantum mechanics, we show that the quantum theory of measurement, supplemented by the strong law of large numbers, leads to a measurement statistics interpretation of quantum mechanics. A probabilistic characterization of the spectrum of a physical quantity is given, and an analysis of the notions of possible values and possible measurement results is carried out.

Between Calculability and Non-Calculability. Issues of Calculability and Predictability in the Physics of Complex Systems. The ability to predict has been a very important qualifier of what constitutes scientific knowledge, ever since the successes of Babylonian and Greek astronomy. More recent is the general appreciation of the fact that in the presence of deterministic chaos, predictability is severely limited (the so-called ‘butterfly effect’): Nearby trajectories diverge during time evolution; small errors typically grow exponentially with time. The system obeys deterministic laws (...) and still is unpredictable, seemingly a paradox for the traditional viewpoint of Laplacian determinisms. With the concept of deterministic chaos the epistemological issue about an adequate understanding of predictability is no longer just a mere philosophical topic. Physicists on the one hand recognize the limits of (long term) predictability, computability and even of scientific knowledge, on the other hand they work on concepts for extending the horizon of predictability. It is shown in this paper that physics of complex systems is useful to clarify the jungle of different meanings of the terms ‘predictability’ and ‘computability’ — also with philosophical implications for understanding science and nature. Today, from the physical point of view, the relevance of the concepts of predictability seems to be underestimated by philosophers as a mere methodological topic. In the paper I analyse the importance of predictability and computability in physics of complex systems. I show a way how to cope with problems of unpredictability and noncomputability. Nine different concepts of predictability and computability (i.e. open solution, sensitivity/chaos, redundancy/chance) are presented, compared and evaluated. (shrink)

Phytomorphology — if concerned with development — often concentrates on correlative changes of form and neglects the aspects of age, time and clock, although the plant's spatial and temporal organisation are intimately interconnected. Common age as measured in physical time by a physical process is compared to biological age as measured by a biological clock based on a biological process. A typical example for a biological clock on the organ level is, for example, a shoot. Its biological age is measured (...) by the biological time unit of a plastochron, which itself is defined by the cyclic-periodic initiation of the leaves. In a controlled environment biological age may replace physical age. However, biological and physical age are not necessarily linearly convertible into each other. In stationary or steady state conditions the repetitive initiation of any organ, unit or module of an articulate plant or plant modular system may define the biological time unit. A linear — monotonous biological process, e.g. axis elongation, may also define a biological time unit as a certain amount of additional growth, e.g. of length. One may speak of periodical and of continuous plastochron or, perhaps, of plastochron and rheochron. A precise measure of biological age is the generalized plastochron index applying to any modular system and module respectively. However, one should be aware that it is based on two clocks, one of them referring to the periodic process of module initiation for counting the integer plastochrons and the other to the continuous plastochron of module growth for the determination of the fraction of one plastochron. The application of the concepts is restricted to phases of stationary or steady state growth and development. In certain cases of non-stationary or non-steady state conditions a normalized-age concept may apply. (shrink)