I present the motivation for experiments which attempt to generate, and verify the existence of, quantum superpositions of two or more states which are by some reasonable criterion ‘macroscopically’ distinct, and show that various a priori objections to this programme made in the literature are flawed. I review the extent to which such experiments currently exist in the areas of free-space molecular diffraction, magnetic biomolecules, quantum optics and Josephson devices, and sketch possible future lines of development of the programme.

This thesis aims to develop a psychologically plausible account of concepts by integrating key insights from philosophy (on the metaphysical basis for concept possession) and psychology (on the mechanisms underlying concept acquisition). I adopt an approach known as informational atomism, developed by Jerry Fodor. Informational atomism is the conjunction of two theses: (i) informational semantics, according to which conceptual content is constituted exhaustively by nomological mind–world relations; and (ii) conceptual atomism, according to which (lexical) concepts have no internal structure. I argue that informational semantics needs to be supplemented by allowing content-constitutive rules of inference (“meaning postulates”). This is because the content of one important class of concepts, the logical terms, is not plausibly informational. And since, it is argued, no principled distinction can be drawn between logical concepts and the rest, the problem that this raises is a general one.

Abstract. Counterfactual reasoning and contextuality is defined and critically evaluated with regard to its nonempirical content. To this end, a uniqueness property of states, explosion views and link observables are introduced. If only a single context associated with a particular maximum set of observables can be operationalized, then a context translation principle resolves measurements of different contexts. COUNTERFACTUALS With the rise of quantum mechanics [1, 2, 3, 4] physics proper entered an ancient and sometimes fierce debate in theology and philosophy: the controversy between realism versus idealism. Whereas realism has been subsumed by the proposition that [5] “some entities sometimes exist without being experienced by any finite mind, ” idealism put forward that “we have not the faintest reason for believing in the existence of unexperienced entities. [[Realism]] has been adopted... solely because it simplifies our view of the universe. ” And whereas these issues can be considered nonoperational and thus metaphysical or even ideological, it is also true that they have inspired a great number of minds, to the effect of stimulating new approaches to quantum mechanics, revealing many theoretical details, quantum phenomena and quantum technologies. The Kochen-Specker theorem [6], for example, was motivated from the onset by scholasticism, as in an early programmatic article [7] Ernst Specker related the discussion on the foundations of quantum mechanics to scholastic

This article is intended as an introduction to the subject of quantum logic, and as a brief survey of the relevant literature. Also discussed here are logics for speci cation and analysis of quantum information systems, in particular, recent work by P. Mateus and A. Sernadas, and also by R. van der Meyden and M. Patra. Overall, our objective is to provide a high-level presentation of the logical aspects of quantum theory. Mateus ' and Sernadas ' EQPL logic is illustrated with a small example, namely the state of an entangled pair of qubits. The "KT" logic of van der Meyden and Patra is demonstrated brie y in the context of the B92 protocol for quantum key distribution. 1

This paper presents the theoretical justification for the use of a particular analytical relation for calculating inferences from answers to cross impact questions. The similarity of the results to other types of analogous applications (i.e., logic regression, logistic models, and the Fermi-Dirac distribution) is indicated. An example of a cross impact analysis in an interactive computer mode is presented. Also discussed is the potential utilization of cross impact as: (1) A modeling tool for the analyst, (2) A consistency analysis tool for the decision maker, (3) A methodology for incorporating policy dependencies in large scale simulations, (4) A structured Delphi Conference for group analysis and discussion ' efforts and (S) A component of a lateral and adaptive management information system.

We derive an experimentally testable criterion for the teleportation of quantum states of continuous variables. This criterion is especially relevant to the recent experiment of Furusawa et al. [Science 282, 706 (1998)] where an input-output fidelity of 0.58 ± 0.02 was achieved for optical coherent states. Our derivation demonstrates that fidelities greater than 1/2 could not have been achieved through the use of a classical channel alone; quantum entanglement was a crucial ingredient in the experiment. 1

Pp. viii + 325. No bibliography; no index. $25.00 (hardcover),

Abstract The universal Turing machine is an anticipatory theory of computability by any digital or quantum machine. However the Church-Turing hypothesis only gives weak anticipation. The construction of the quantum computer (unlike classical computing) requires theory with strong anticipation. Category theory provides the necessary coordinate-free mathematical language which is both constructive and non-local to subsume the various interpretations of quantum theory in one pullback/pushout Dolittle diagram. This diagram can be used to test and classify physical devices and proposed algorithms for weak or strong anticipation. Quantum Information Science is more than a merger of Church-Turing and quantum theories. It has constructively to bridge the non-local chasm between the weak anticipation of mathematics and the strong anticipation of physics.

Positive and negative features of the Copenhagen interpretation are discussed. As positive features can be mentioned its pragmatism and its awareness of the crucial role of measurement. However, the main part of the contribution is devoted to the negative features, to wit, its pragmatism (once again), its confounding of preparation and measurement, its classical account of measurement, its completeness claims, the ambiguity of its notion of correspondence, its confused notion of complementarity. It is demonstrated how confusions and paradoxes stemming from the negative features of the Copenhagen interpretation can be dealt with in an amended interpretation, to be referred to as ‘neo-Copenhagen interpretation’, in which the role of the measuring instrument is taken seriously by recognizing the quantum mechanical character of its interaction with the microscopic object. The ensuing necessity of extending the notion of a quantum mechanical observable from the Hermitian operator of the standard formalism to the positive operator-valued measure of a generalized formalism is demonstrated to yield a sound mathematical basis for a transition from the Copenhagen contextualistic-realist interpretation to the neo-Copenhagen empiricist one. Applications to the uncertainty relations and to the Bell inequalities are briefly discussed. 1

Abstract. In this paper we present a survey of the use of differential