Addressing a wide range of topics, from Newton to Post-Kuhnian philosophy of science, these essays critically examine themes that have been central to the influential work of philosopher Michael Friedman.

This essay is a discussion of the philosophical and foundational issues that arise in non-relativistic quantum theory. After introducing the formalism of the theory, I consider: characterizations of the quantum formalism, empirical content, uncertainty, the measurement problem, and non-locality. In each case, the main point is to give the reader some introductory understanding of some of the major issues and recent ideas.

An outstanding problem in so-called modal interpretations of quantum mechanics has been the specification of a dynamics for the properties introduced in such interpretations. We develop a general framework (in the context of the theory of stochastic processes) for specifying a dynamics for interpretations in this class, focusing on the modal interpretation by Vermaas and Dieks. This framework admits many empirically equivalent dynamics. We give some examples, and discuss some of the properties of one of them. This approach is applicable (...) to a wider class of theories, in particular, those using (discrete) strict effective—as in decoherence theory—superselection rules. (shrink)

Quantum mechanics has sometimes been taken to be an empiricist (vs. realist) theory. I state the empiricist's argument, then outline a recently noticed type of measurement--protective measurement--that affords a good reply for the realist. This paper is a reply to scientific empiricism (about quantum mechanics), but is neither a refutation of that position, nor an argument in favor of scientific realism. Rather, my aim is to place realism and empiricism on an even score in regards to quantum theory.

Is the quantum-logic interpretation dead? Its near total absence from current discussions about the interpretation of quantum theory suggests so. While mathematical work on quantum logic continues largely unabated, interest in the quantum-logic interpretation seems to be almost nil, at least in Anglo-American philosophy of physics. This paper has the immodest purpose of changing that fact. I shall argue that while the quantum-logic interpretation faces challenges, it remains a live option. The usual objections either miss the mark, or admit a (...) reasonable answer, or fail to decide the issue conclusively. (shrink)

Is the quantum-logic interpretation dead? Its near total absence from current discussions about the interpretation of quantum theory suggests so. While mathematical work on quantum logic continues largely unabated, interest in the quantum-logic interpretation seems to be almost nil, at least in Anglo-American philosophy of physics. This paper has the immodest purpose of changing that fact. I shall argue that while the quantum-logic interpretation faces challenges, it remains a live option. The usual objections either miss the mark, or admit a (...) reasonable answer, or fail to decide the issue conclusively. (shrink)

Bohr’s reply to Einstein, Podolsky, and Rosen’s argument for the incompleteness of quantum theory is notoriously difficult to unravel. It is so diffcult, in fact, that over 60 years later, there remains important work to be done understanding it. Work by Fine , Beller and Fine , and Beller goes a long way towards correcting earlier misunderstandings of Bohr’s reply. This essay is intended as a contribution to the program of getting to the truth of the matter, both historically and (...) philosophically. In a paper of this length, a full account of Bohr’s reply is impossible, and so I shall focus on one issue where it seems further clarification is required, namely, Bohr’s attempt to illustrate EPR’s argument by means of a thought experiment. In addition, I shall attempt to clarify a few other points which, however minor, have apparently contributed to misunderstandings of Bohr’s position. As the title of this paper suggests, an account of these few points does not constitute an account of Bohr’s reply, but it is an important step in that direction. (shrink)

Taking a cue from Bohr’s use of the notion of a reference frame in his reply to EPR’s argument against the completeness (and consistency) of standard quantum theory, this paper presents an analysis ofthe role of reference frames in the situation considered by EPR, using a quantum‐theoretical account of physical reference frames based on the work of Mackey, and Aharonov and Kaufherr. That analysis appears to justify at least some crucial aspects of a Bohrian reply to EPR.

The conceptual structure of orthodox quantum mechanics has not provided a fully satisfactory and coherent description of natural phenomena. With particular attention to the measurement problem, we review and investigate two unorthodox formulations. First, there is the model advanced by GRWP, a stochastic modification of the standard Schrödinger dynamics admitting statevector reduction as a real physical process. Second, there is the ontological interpretation of Bohm, a causal reformulation of the usual theory admitting no collapse of the statevector. Within these two (...) seemingly quite different approaches, we discuss in a comparative manner, several points: The meaning of the state vector, the status of quantum probability, the legitimacy of attributing macro objective properties to physical systems, and the possibility of retrieving the classical limit. Finally, we consider aspects of non-locality and relevant difficulties with formulating a relativistic generalization of the two approaches. (shrink)

Stapp's attempt to derive Bell's Inequality from a weak locality condition while retaining indeterminism, requires careful scrutiny to ensure unambiguous definitions and valid reasoning. Such scrutiny reveals that the argument is fallacious. This result is obtained without commitment to any particular formal analysis of truth conditions for counterfactuals nor to conditions for world similarity.

Economist Frank Knight drew a distinction between decisions under risk and decisions under uncertainty. Despite the significance of this distinction for decision theory, we argue that there has been inadequate attention to the difficulties involved in classifying decision situations into these categories. Using the risk assessment of carbon nanotubes as an example, we show that it is often unclear whether there is adequate information to classify a decision situation as being under risk as opposed to uncertainty. We conclude by providing (...) two suggestions for responding to these difficulties: treating decisions as real-world experiments; and promoting broadly based deliberation about quantitative information. (shrink)

I consider the fact that there are a number of interesting ways to ‘reconstruct’ quantum theory, and suggest that, very broadly speaking, a form of ‘instrumentalism’ makes good sense of the situation. This view runs against some common wisdom, which dismisses instrumentalism as ‘cheap’. In contrast, I consider how an instrumentalist might think about the reconstruction theorems, and, having made a distinction between ‘reconstructing’ quantum theory and ‘reinventing’ quantum theory, I suggest that there is an adequate instrumentalist approach to the (...) theory that invokes both. (shrink)

I review the modal interpretation of quantum mechanics, some versions of which rely on the biorthonormal decomposition of a statevector to determine which properties are physically possessed. Some have suggested that these versions fail in the case of inaccurate measurements, i.e., when one takes tails of the wavefunction into account. I show that these versions of the modal interpretation are satisfactory in such cases. I further suggest that a more general result is possible, namely, that these versions of the modal (...) interpretation never encounter the sort of trouble that has been claimed to arise in the case of inaccurate measurement. (shrink)

Is the quantum-logic interpretation dead? Its near total absence from current discussions about the interpretation of quantum theory suggests so. While mathematical work on quantum logic continues largely unabated, interest in the quantum-logic interpretation seems to be almost nil, at least in Anglo-American philosophy of physics. This paper has the immodest purpose of changing that fact. I shall argue that while the quantum-logic interpretation faces challenges, it remains a live option. The usual objections either miss the mark, or admit a (...) reasonable answer, or fail to decide the issue conclusively. (shrink)

Since the fundamental challenge that I laid at the doorstep of the pluralists was to defend, with nonderivative models, a strong notion of genic cause, it is fatal that Waters has failed to meet that challenge. Waters agrees with me that there is only a single cause operating in these models, but he argues for a notion of causal ‘parsing’ to sustain the viability of some form of pluralism. Waters and his colleagues have some very interesting and important ideas about (...) the sciences, involving pluralism and parsing or partitioning causes, but they are ideas in search of an example. He thinks he has found an example in the case of hierarchical and genic selection. I think he has not. (shrink)

I explore an agent-based model of the development and dissemination of scientific theory that makes very little use of any pre-defined (such as partnerships or collaborations). In these models, under a broad range of values of the parameters, widespread (but not universal) about scientific theory emerges. Moreover, the residual disagreement turns out to be important to developing new theories in the face of new evidence.

‘Seeing is believing’ perhaps means that some visual experience provides good evidence for some claims that go beyond the content of the experience. Intuition—intellectual ‘seeming’—does not provide similarly good evidence, at least not for metaphysical claims, or so I shall argue. In §2, I sketch the conception of ‘metaphysics’ that is in use here, a conception that leads naturally to a problem about what counts as evidence in metaphysics. Some have suggested that intuition counts. In §3 I raise some doubts (...) (but not radical skeptical doubts) about intuition. These doubts are directed specifically at Bealer’s (1998) account of philosophical intuition. In §4 I will consider an argument in favor of the appeal to rational intuition as evidence in philosophy, and suggest that the argument is circular. I conclude §4 with some additional doubts about intuition, focused on whether intuitions could ever be ‘calibrated’. (shrink)

We consider an extension of signaling games to the case of prediction, where one agent perceives the current state of the world and sends a signal. The second agent perceives this signal, and makes a prediction about the next state of the world. We suggest that such games may be the basis of a model for the evolution of successful theorizing about the world.

It has been argued, partly from the lack of any widely accepted solution to the measurement problem, and partly from recent results from quantum information theory, that measurement in quantum theory is best treated as a black box. However, there is a crucial difference between ‘having no account of measurement' and ‘having no solution to the measurement problem'. We know a lot about measurements. Taking into account this knowledge sheds light on quantum theory as a theory of information and computation. (...) In particular, the scheme of ‘one-way quantnum computation' takes on a new character in light of the role that reference frames play in actually carrying out any one-way quantum comptuation. ‡Thanks to audiences at the PSA and the Centre for Time, University of Sydney, for helpful comments and questions. †To contact the author, please write to: Department of Philosophy, University of South Carolina, Columbia, SC 29208; e-mail: [email protected]. (shrink)

This paper proposes a logic, motivated by modal interpretations, in which every quantum mechanics propositions has a truth-value. This logic is completely classical, hence violates the conditions of the Kochen-Specker theorem. It is shown how the violation occurs, and it is argued that this violation is a natural and acceptable consequence of modal interpretations. It is shown that despite its classicality, the proposed logic is empirically indistinguishable from quantum logic.

This paper proposes a logic, motivated by modal interpretations, in which every quantum mechanics propositions has a truth-value. This logic is completely classical, hence violates the conditions of the Kochen-Specker theorem. It is shown how the violation occurs, and it is argued that this violation is a natural and acceptable consequence of modal interpretations. It is shown that despite its classicality, the proposed logic is empirically indistinguishable from quantum logic.

This chapter reflects on transhumanism from a Christian perspective, specifically with reference to the Biblical teaching that human beings are made in the “image” and “likeness” of God. It considers a version of that teaching that is seemingly as permissive as could be about “transhumanist technologies,” and concludes that even that version places significant limits on the pursuit and adoption of such technologies. Those limits are far more restrictive than the limits acknowledged by prominent transhumanists, particularly those with a specific (...) focus on proposals aimed at substantially lengthening the average human lifespan. (shrink)

If observation is 'theory-laden', how can there be 'observationally equivalent theories'? How can the observations 'laden' by one theory be 'the same as' those 'laden' by another? The answer might lie in the expressibility of observationally equivalent theories in a common mathematical formalism.

I introduce and review the most recent and most promising model of state vector reduction, that of Ghirardi, Rimini, Weber, and Pearle. This model requires the specification of a reduction basis. At least two questions therefore arise: Are there physical reasons to choose one basis rather than another? Does the choice made lead to any undesirable consequences? I argue that there arephysical reasons to choose from a certain class of reduction bases (a class which includes the choice made by the (...) authors mentioned above), and that such a choice does not lead to problems, contra an argument by Albert and Vaidman. (shrink)

If observation is ‘theory-laden’, how can there be ‘observationally equivalent theories’? How can the observations ‘laden’ by one theory be ‘the same as’ those ‘laden’ by another? The answer might lie in the expressibility of observationally equivalent theories in a common mathematical formalism.