Measurement and the Justification of the Statistical Postulate in Bohm's Causal Interpretation of Quantum Mechanics

I briefly sketch Bohm's causal interpretation (BCI) and its solution to the measurement problem. Crucial to BCI's no-collapse account of both ideal and non-ideal measurement is the existence of particles in addition to wavefunctions. The particles in their role as the producers of the observable experimental outcomes render practical considerations, such as what observables can be reasonably measured or how to get rid of interference terms in non-ideal measurements, secondary to BCI's account of measurement. I then explain why it is not easy for BCI to justify its statistical postulate. To successfully justify the postulate would be to solve the distribution problem. Two proposed deterministic solutions to this problem are only briefly set out and not discussed in detail. BCI can solve the measurement problem whether or not the distribution problem is solved. However, if the distribution problem is not solved, BCI cannot be shown to be empirically adequate. This revised version was published online in June 2006 with corrections to the Cover Date.     

Bohm,Spin, and the Bell Inequalities

In this paper I discuss how Bohm's interpretation models spin measurements and how the two ways in which spin is a contextual property pertains to the Kochen-Specker theorem. I then present locality principles from which a Bell Inequality can be derived, and I identify which of the locality principles Bohm's interpretation violates at which times. I also present reasons why the spin vector should not be attributed to the Bohmian particles.     

Problems with the ‘physical’ in physicalism

Hempel's Dilemma is a challenge that has to be met by any formulation of physicalism that specifies the physical by reference to a particular physical theory. It poses the problem that if one's specification of the physical is ‘current’ physical theory, then the physicalism which depends on it is false because current physics is false; and if the specification of the physical is a future or an ideal physics, the physicalism based on it would be trivial as it would be tautologously true, or because very little (if anything at all) can be inferred from or about a physics that does not yet exist. I review the reasons for thinking that the dilemma is a perpetual problem for currentist specifications of the physical, then introduce the argument that the standard positions on the specification question are wanting because they lack a generality which physicalism is generally accepted to have. I end with a suggestion for a way forward for physicalism.     

Aristotle on Modality: Nicholas DenyerNever Will and Cannot

In De Caelo 1: 11-12 Aristotle argued that whatever is and always will be true is necessarily true. His argument works, once we grant him the highly plausible principle that if something is true, then it can be false if and only if it can come to be false. For example, assume it true that the sun is and always will be hot. No proposition of this form can ever will be hot. No proposition of this form can ever come to be false. Hence this proposition cannot be false. Hence it is necessarily true, and so too is anything that follows from it. In particular, it is necessarily true that the sun is hot. Moreover, if the sun not only is and always will be hot, but also always has been, then it follows by similar reasoning that the sun not only cannot now fail to be hot, but also never could have failed. Anything everlastingly true is therefore, in the strictest sense of the term, necessarily true.     

The Unique Groundability of Temporal Facts

The A‐theory and the B‐theory advance competing claims about how time is grounded. The A‐theory says that A‐facts are more fundamental in grounding time than are B‐facts, and the B‐theory says the reverse. We argue that whichever theory is true of the actual world is also true of all possible worlds containing time. We do this by arguing that time is uniquely groundable: however time is actually grounded, it is necessarily grounded in that way. It follows that if either the A‐theory or the B‐theory is actually false, then it is necessarily false.     

The copredication argument

The standard view of truth-conditional semantics is that it is world-involving in the sense that a theory that specifies truth conditions eo ipso is a theory that specifies the way the world must be if the target sentences are to be true. It would appear to follow that the semantic properties of expressions, such as nominals, specify the very worldly objects that make true or false the sentences that host the nominals. Chomsky and others have raised a fundamental complaint against this thought: perfectly quotidian nominals, such as London or book, may occur copredicatively as a single argument of categorically mismatched predicates, which prima facie preclude a coherent uniform construal of the nominal argument. The argument has hitherto been presented via examples that challenge the standard view. My aim here is to present the argument explicitly, defend it against some likely counterclaims, and resolve what might appear to be a decisive consideration against the conclusion of the argument, viz., if nominals as copredicatively occurring do not contribute uniform worldly entities, then how can the copredicative constructions be counted as true?     

The suggestive properties of quantum mechanics without the collapse postulate

Everett proposed resolving the quantum measurement problem by dropping the nonlinear collapse dynamics from quantum mechanics and taking what is left as a complete physical theory. If one takes such a proposal seriously, then the question becomes how much of the predictive and explanatory power of the standard theory can one recover without the collapse postulate and without adding anything else. Quantum mechanics without the collapse postulate has several suggestive properties, which we will consider in some detail. While these properties are not enough to make it acceptable given the usual standards for a satisfactory physical theory, one might want to exploit these properties to cook up a satisfactory no-collapse formulation of quantum mechanics. In considering how this might work, we will see why any no-collapse theory must generally fail to satisfy at least one of two plausible-sounding conditions.     

Presentism and the Triviality Objection

Presentism is usually understood as the thesis that only the present exists whereas the rival theory of eternalism is usually understood as the thesis that past, present, and future things are all equally real. The significance of this debate has been threatened by the so-called triviality objection, which allegedly shows that the presentist thesis is either trivially true or obviously false: Presentism is trivially true if it is read as saying that everything that exists now is present, and it is obviously false if read as saying that everything that has existed, exits or will exist is present. If eternalism is taken as the negation of presentism, it is also either trivially false or obviously true. In this paper, I try to respond to the triviality objection on behalf of presentism. In second section, I will examine how the argument proceeds. In third section, I will reflect on three possible ways to respond but will argue that none of them succeeds in giving a satisfactory solution. I will then try to clarify the core idea of presentism and to suggest that if we characterise presentism accurately, the problem will disappear. In fourth section, I will offer a plausible definition of presentism and will show how it can avoid the triviality objection and demonstrate why it is advantageous to accept the version of presentism I offer.     

The Intrinsic Quantum Nature of Nash Equilibrium Mixtures

In classical game theory the idea that players randomize between their actions according to a particular optimal probability distribution has always been viewed as puzzling. In this paper, we establish a fundamental connection between n-person normal form games and quantum mechanics (QM), which eliminates the conceptual problems of these random strategies. While the two theories have been regarded as distinct, our main theorem proves that if we do not give any other piece of information to a player in a game, than the payoff matrix—the axiom of “no-supplementary data” holds—then the state of mind of a rational player is algebraically isomorphic to a pure quantum state. The “no supplementary data” axiom is captured in a Lukasiewicz’s three-valued Kripke semantics wherein statements about whether a strategy or a belief of a player is rational are initially indeterminate i.e. neither true, nor false. As a corollary, we show that in a mixed Nash equilibrium, the knowledge structure of a player implies that probabilities must verify the standard “Born rule” postulate of QM. The puzzling “indifference condition” wherein each player must be rationally indifferent between all the pure actions of the support of his equilibrium strategy is resolved by his state of mind being described by a “quantum superposition” prior a player is asked to make a definite choice in a “measurement”. Finally, these results demonstrate that there is an intrinsic limitation to the predictions of game theory, on a par with the “irreducible randomness” of quantum physics.     

The argument from agreement: How universal values undermine moral realism

The most popular argument against moral realism is the argument from disagreement: if there are mind‐independent moral facts, then we would not expect to find as much moral disagreement as we in fact do; therefore, moral realism is false. In this paper, I develop the flipside of this argument. According to this argument from agreement, we would expect to find lots of moral disagreement if there were mind‐independent moral facts. But we do not, in fact, find much moral disagreement; therefore, moral realism is false. I defend the argument, explain the empirical evidence that supports it, and show what makes this challenge novel and powerful.     

波函数的实在性分析

波函数是量子力学的核心概念。波函数的实在性问题一直是科学实在论与反实在论争论的焦点之一。20世纪上半叶量子力学研究主要是检验量子力学的理论是否正确或完备,仅有少量量子技术产品问世。1935年爱因斯坦、波多尔斯基和罗森(EPR)发表的《能认为量子力学对物理实在的描述是完备的吗?》一文,提出了EPR关联——量子纠缠,直接引发了对量子力学基本问题的论争。(Einstein,Podolsky and Rosen,pp.777-780)基于EPR量子纠缠,1993年本内特(Bennett)等6位科学家在《物理评论快报》发表题为《经由经典和EPR通道传送未知量子态》的重要论文,引发了一系列有关量子信息与量子技术的研究,形成了量子信息理论、量子控制论、量子技术等新的量子科技理论。量子纠缠     

Significance Testing with No Alternative Hypothesis: A Measure of Surprise

A pure significance test would check the agreement of a statistical model with the observed data even when no alternative model was available. The paper proposes the use of a modified p-value to make such a test. The model will be rejected if something surprising is observed (relative to what else might have been observed). It is shown that the relation between this measure of surprise (the s-value) and the surprise indices of Weaver and Good is similar to the relationship between a p-value, a corresponding odds-ratio, and a logit or log-odds statistic. The s-value is always larger than the corresponding p-value, and is not uniformly distributed. Difficulties with the whole approach are discussed.     

Antecedent Priming at Trace Positions: Evidence from German Scrambling

In Chomsky's theory of grammar, syntactic representations are said to contain movement traces, i.e., syntactically active but phonetically null copies of displaced constituents. Correspondingly, traces have been claimed to form part of the processing of sentence structure by showing that at trace sites the parser reactivates a moved constituent. This view has been contested, however, by researchers arguing that experimental findings can better be explained in terms of direct associations between subcategorizers and arguments. Against this background, we investigate antecedent reactivation effects in scrambled double-object constructions of German in two cross-modal priming experiments. We found significant priming effects at positions at which a movement analysis of these constructions would postulate an empty category, thus suggesting that the antecedent is indeed reactivated at the gap position. The Direct Association Hypothesis, on the other hand, cannot account for the priming effects we found. Implications for processing and for syntactic analyses of scrambling in German will be discussed.     

What time travelers may be able to do

Kadri Vihvelin, in “What time travelers cannot do” (Philos Stud 81:315–330, 1996), argued that “no time traveler can kill the baby who in fact is her younger self”, because (V1) “if someone would fail to do something, no matter how hard or how many times she tried, then she cannot do it”, and (V2) if a time traveler tried to kill her baby self, she would always fail. Theodore Sider (Philos Stud 110:115–138, 2002) criticized Vihvelin’s argument, and Ira Kiourti (Philos Stud 139:343–352, 2008) criticized both Vihvelin’s argument and Sider’s critique. I present a critique of Vihvelin’s argument different from both Sider’s and Kiourti’s critiques: I argue in a novel way that both V1 and V2 are false. Since Vihvelin’s argument might be understood as providing a challenge to the possibility of time travel, if my critique succeeds then time travel survives such a challenge unscathed.     

The explanatory power of local miracle compatibilism

Local miracle compatibilists claim that we are sometimes able to do otherwise than we actually do, even if causal determinism obtains. When we can do otherwise, it will often be true that if we were to do otherwise, then an actual law of nature would not have been a law of nature. Nevertheless, it is a compatibilist principle that we cannot do anything that would be or cause an event that violates the laws of nature. Carl Ginet challenges this nomological principle, arguing that it is not always capable of explaining our inability to do otherwise. In response to this challenge, I point out that this principle is part of a defense against the charge that local miracle compatibilists are committed to outlandish claims. Thus it is not surprising that the principle, by itself, will often fail to explain our inability to do otherwise. I then suggest that in many situations in which we are unable to do otherwise, this can be explained by the compatibilist’s analysis of ability, or his criteria for the truth of ability claims. Thus, the failure of his nomological principle to explain the falsity of certain ability claims is no strike against local miracle compatibilism.     

THE PHYSICS OF DAVID BOHM AND ITS RELEVANCE TO PHILOSOPHY AND THEOLOGY

Abstract. The purpose of this paper is to analyze David Bohm's work in terms of physics, philosophy, and theology. First, I discuss the development of Bohm's thought since 1951. Then, using the methodology of Imre Lakatos, I evaluate the scientific status of his research program. Next, I explore the philosophical dimensions of Bohm's views in which realist and idealist, monist and dualist, contingent and determinist outlooks occur in creative tension. Finally, I suggest ways in which Bohm's ideas are relevant to theology through concepts of God and cosmos, beauty and purpose, grace and free will, church, self and evil.

The entire universe is basically a single, indivisible…but flexible and ever changing, unit (Bohm 1951, 140).

     

Future Contingents and Relative Truth

If it is not now determined whether there will be a sea battle tomorrow, can an assertion that there will be one be true? The problem has persisted because there are compelling arguments on both sides. If there are objectively possible futures which would make the prediction true and others which would make it false, symmetry considerations seem to forbid counting it either true or false. Yet if we think about how we would assess the prediction tomorrow, when a sea battle is raging (or not), it seems we must assign the utterance a definite truth-value. I argue that both arguments must be given their due, and that this requires relativizing utterance-truth to a context of assessment. I show how this relativization can be handled in a rigorous formal semantics, and I argue that we can make coherent sense of assertion without assuming that utterances have their truth-values absolutely.     

“Love of same,love of other”

The positions in feminist theory and theology tend to be polarized between so‐called essentialists and constructionists. Yet, despite apparent anthropological dissension, both parties try to substantiate political and ecclesiastical claims through definitions: what is sexual difference, what is gender, what is a woman, what is she not. For the purpose of mending how we usually approach these questions, I claim instead that the most important theological issue in the realities of males and females is not that their bodies “work” differently, nor that their social positions usually are different and “mean” differently in different cultures, but that they take part in the constitution, recreation and representation of different human subject positions of which there are everywhere and always at least two. My tentative arguments are developed from engaging with the Swiss theologian Karl Barth and the French philosopher Luce Irigaray.     

Scalar Properties, Binary Judgments

In the moral realm, our deontic judgments are usually (always?) binary. An act (or omission) is either morally forbidden or morally permissible. ¹ 1 I realize that I appear to be omitting the category of ‘morally required’ here. But that category does not affect my analysis in part because we can always substitute for a morally required act a morally forbidden omission to act. The question would then be whether the omission to act is permissible or forbidden. In any event, my focus is on deontic boundaries, and it is immaterial how many there are. Thus, I shall continue to speak of acts being morally forbidden or permissible.
Yet the determination of an act's deontic status frequently turns on the existence of properties that are matters of degree. In what follows I shall give several examples of binary moral judgments that turn on scalar properties, and I shall claim that these examples should puzzle us. How can the existence of a property to a specific degree demarcate a boundary between an act's being morally forbidden and its not being morally forbidden? Why aren't our moral judgments of acts scalar in the way that the properties on which those judgments are based are scalar, so that acts, like states of affairs, can be morally better or worse rather than right or wrong? I conceive of this inquiry as operating primarily within the realm of normative theory. Presumably it will give aid and comfort to consequentialists, who have no trouble mapping their binary categories onto scalar properties. For example, a straightforward act utilitarian, for whom one act out of all possible acts is morally required (and hence permissible) and all others morally forbidden, can, in theory at least, provide an answer to every one of the puzzles I raise. And, in theory, so can all other types of act and rule consequentialists. They will find nothing of interest here beyond embarrassment for their deontological adversaries. The deontologists, however, must meet the challenges of these puzzles. And for them, the puzzles may raise not just normative questions, but questions of moral epistemology and moral ontology. Just how do we know that the act consequentialist's way of, say, trading off lives against lives is wrong? For example, do we merely intuit that taking one innocent, uninvolved person's life to save two others is wrong? Can our method of reflective equilibrium work if we have no theory by which to rationalize our intuitions? And what things in the world make it true, if it is true, that one may not make the act consequentialist's tradeoff? I do not provide any answers to these questions any more than I provide answers to the normative ones. But they surely lurk in the background.     

Counterpossibles in Science: The Case of Relative Computability

I develop a theory of counterfactuals about relative computability, i.e. counterfactuals such as

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