The British Journal for the Philosophy of Science - current issue

Relational Quantum Mechanics and the Determinacy Problem

Brown, M. J. — Fri, 20 Nov 2009 08:50:24 PST

Carlo Rovelli's relational interpretation of quantum mechanics holds that a system's states or the values of its physical quantities as normally conceived only exist relative to a cut between a system and an observer or measuring instrument. Furthermore, on Rovelli's account, the appearance of determinate observations from pure quantum superpositions happens only relative to the interaction of the system and observer. Jeffrey Barrett ([1999]) has pointed out that certain relational interpretations suffer from what we might call the ‘determinacy problem', but Barrett misclassifies Rovelli's interpretation by lumping it in with Mermin's view, as Rovelli's view is quite different and has resources to escape the particular criticisms that Barrett makes of Mermin's view. Rovelli's interpretation still leaves us with a paradox having to do with the determinacy of measurement outcomes, which can be accepted only if we are willing to give up on certain elements of the ‘absolute’ view of the world.

Introduction

Relational Quantum Mechanics

Barrett on Relational Interpretations

A Puzzle about Relative States

Canonical Cuts

Is Quantum Consistency Enough?

Perfect Symmetries

Healey, R. — Fri, 20 Nov 2009 08:50:24 PST

While empirical symmetries relate situations, theoretical symmetries relate models of a theory we use to represent them. An empirical symmetry is perfect if and only if any two situations it relates share all intrinsic properties. Sometimes one can use a theory to explain an empirical symmetry by showing how it follows from a corresponding theoretical symmetry. The theory then reveals a perfect symmetry. I say what this involves and why it matters, beginning with a puzzle that is resolved by the subsequent analysis. I conclude by pointing to applications and implications of the ideas developed earlier in the paper.

Introduction

Is Faraday in the Same Boat as Galileo?

Empirical Symmetries

Theoretical Symmetries

Explaining Empirical Symmetries

Conclusion

Appendix A

Appendix B

Are Linguists Better Subjects?

Culbertson, J., Gross, S. — Fri, 20 Nov 2009 08:50:24 PST

Who are the best subjects for judgment tasks intended to test grammatical hypotheses? Michael Devitt ([2006a], [2006b]) argues, on the basis of a hypothesis concerning the psychology of such judgments, that linguists themselves are. We present empirical evidence suggesting that the relevant divide is not between linguists and non-linguists, but between subjects with and without minimally sufficient task-specific knowledge. In particular, we show that subjects with at least some minimal exposure to or knowledge of such tasks tend to perform consistently with one another—greater knowledge of linguistics makes no further difference—while at the same time exhibiting markedly greater in-group consistency than those who have no previous exposure to or knowledge of such tasks and their goals.

Introduction

Background and Clarification

Previous Experiments

Our Experiment

The Context of Devitt's Claim and His Psychological Model

Appendix

Physical Causation and Difference-Making

Ney, A. — Fri, 20 Nov 2009 08:50:24 PST

This paper examines the relationship between physical theories of causation and theories of difference-making. It is plausible to think that such theories are compatible with one another as they are aimed at different targets: the former, an empirical account of actual causal relations; the latter, an account that will capture the truth of most of our ordinary causal claims. The question then becomes: what is the relationship between physical causation and difference-making? Is one kind of causal fact more fundamental than the other? This paper defends causal foundationalism: the view that facts about difference-making are dependent on the obtaining of facts about physical causation. However, the paper's main goal is to clarify the structure of the debate. At the end of the paper, it is shown how settling the issue about the relationship between physical theories of causation and theories of difference-making has more than mere intrinsic interest in unifying the very different pursuits that have been undertaken in the philosophy of causation. It can help to break a stalemate that has arisen in the current debate about mental causation.

Two Pursuits in the Philosophy of Causation

Causal Foundationalism and its Rivals

Anti-foundationalism: Russell and Field

Against the Russell/Field Arguments

The Case for Foundationalism

Causing and ‘Causing’

An Application: Mental Causation

SAD Computers and Two Versions of the Church-Turing Thesis

Button, T. — Fri, 20 Nov 2009 08:50:24 PST

Recent work on hypercomputation has raised new objections against the Church–Turing Thesis. In this paper, I focus on the challenge posed by a particular kind of hypercomputer, namely, SAD computers. I first consider deterministic and probabilistic barriers to the physical possibility of SAD computation. These suggest several ways to defend a Physical version of the Church–Turing Thesis. I then argue against Hogarth's analogy between non-Turing computability and non-Euclidean geometry, showing that it is a non-sequitur. I conclude that the Effective version of the Church–Turing Thesis is unaffected by SAD computation.

SAD Computability

1.1 The basic idea of SAD computation

1.2 Avoiding supertasks

1.3 Davies's model of SAD computation

1.4 Hogarth's model of SAD computation

1.5 Generalizing SAD computers

Physical Computability

2.1 The Physical Church–Turing Thesis

2.2 Deterministic barriers to physical computation

2.3 Probabilistic barriers to physical computation

Effective Computability

3.1 The Effective Church–Turing Thesis

3.2 Hogarth's challenge to the Effective Church–Turing Thesis

3.3 Arguing from SAD computability is a non-sequitur

3.4 SAD computability is built from finitary computability

Concluding Remarks

Commutativity or Holism? A Dilemma for Conditionalizers

Weisberg, J. — Fri, 20 Nov 2009 08:50:24 PST

Conditionalization and Jeffrey Conditionalization cannot simultaneously satisfy two widely held desiderata on rules for empirical learning. The first desideratum is confirmational holism, which says that the evidential import of an experience is always sensitive to our background assumptions. The second desideratum is commutativity, which says that the order in which one acquires evidence shouldn't affect what conclusions one draws, provided the same total evidence is gathered in the end. (Jeffrey) Conditionalization cannot satisfy either of these desiderata without violating the other. This is a surprising problem, and I offer a diagnosis of its source. I argue that (Jeffrey) Conditionalization is inherently anti-holistic in a way that is just exacerbated by the requirement of commutativity. The dilemma is thus a superficial manifestation of (Jeffrey) Conditionalization's fundamentally anti-holistic nature.

1 Introduction

2 Clarifying Commutativity and Holism

3 The Dilemma for Strict Conditionalization

4 The Dilemma for Jeffrey Conditionalization

4.1 Jeffrey conditionalization and commutativity

4.2 The tension with holism

4.3 Loose ends and technical worries

5 Diagnosis

6 Morals and Connections

An Organizational Account of Biological Functions

Mossio, M., Saborido, C., Moreno, A. — Fri, 20 Nov 2009 08:50:24 PST

In this paper, we develop an organizational account that defines biological functions as causal relations subject to closure in living systems, interpreted as the most typical example of organizationally closed and differentiated self-maintaining systems. We argue that this account adequately grounds the teleological and normative dimensions of functions in the current organization of a system, insofar as it provides an explanation for the existence of the function bearer and, at the same time, identifies in a non-arbitrary way the norms that functions are supposed to obey. Accordingly, we suggest that the organizational account combines the etiological and dispositional perspectives in an integrated theoretical framework.

Introduction

Dispositional Approaches

Etiological Theories

Biological Self-maintenance

4.1 Closure, teleology, and normativity

4.2 Organizational differentiation

Functions

5.1 C₁: Contributing to the maintenance of the organization

5.2 C₂: Producing the functional trait

Implications and Objections

6.1 Functional versus useful

6.2 Dysfunctions, side effects, and accidental contributions

6.3 Proper functions and selected effects

6.4 Reproduction

6.5 Relation with other ‘unitarian’ approaches

Conclusions

HANNE ANDERSEN, PETER BARKER and XIAN CHEN The Cognitive Structure of Scientific Revolutions

Thagard, P. — Fri, 20 Nov 2009 08:50:24 PST

JON WILLIAMSON Bayesian Nets and Causality

Glymour, C. — Fri, 20 Nov 2009 08:50:24 PST

Response to Glymour

Williamson, J. — Fri, 20 Nov 2009 08:50:24 PST