Nancy Cartwright believes that we live in a Dappled World-a world in which theories, principles, and methods applicable in one domain may be inapplicable in others and in which there are no universal principles. One of the targets of Cartwright’s arguments for this conclusion is the Causal Markov condition, a condition which has been proposed as a universal condition on causal structures.2 The Causal Markov condition, Cartwright argues, is applicable only in a limited domain of special cases and thus cannot be used as a universal principle in causal discovery. I have no dispute with any of these claims here. Rather, I wish to argue for a very limited thesis: that the Causal Markov condition is applicable in the specific domain of microscopic quantum mechanical systems; further, that the condition can fruitfully be applied to the much discussed EPR setup. This is perhaps a surprising conclusion, for it is precisely in this domain that Cartwright’s arguments against the Causal Markov condition have been considered to be the most successful.
Nancy Cartwright believes that we live in a Dappled World-a world in which theories, principles, and methods applicable in one domain may be inapplicable in others and in which there are no universal principles. One of the targets of Cartwright’s arguments for this conclusion is the Causal Markov condition, a condition which has been proposed as a universal condition on causal structures.2 The Causal Markov condition, Cartwright argues, is applicable only in a limited domain of special cases and thus cannot be used as a universal principle in causal discovery. I have no dispute with any of these claims here. Rather, I wish to argue for a very limited thesis: that the Causal Markov condition is applicable in the specific domain of microscopic quantum mechanical systems; further, that the condition can fruitfully be applied to the much discussed EPR setup. This is perhaps a surprising conclusion, for it is precisely in this domain that Cartwright’s arguments against the Causal Markov condition have been considered to be the most successful.
It is still a matter of controversy whether the Principle of the Common Cause (PCC) can be used as a basis for sound causal inference. It is thus to be expected that its application to quantum mechanics should be a correspondingly controversial issue. Indeed the early 90's saw a flurry of papers addressing just this issue in connection with the EPR correlations. Yet, that debate does not seem to have caught up with the most recent literature on causal inference generally, which has moved on to consider the virtues of a generalized PCC-inspired condition, the so-called Causal Markov Condition (CMC). In this paper we argue that the CMC is an appropriate benchmark for debating possible causal explanations of the EPR corrleations. But we go on to take issue with some pronouncements on EPR by defenders of the CMC.
It has been claimed that quantum mechanics is a non-local theory, i.e., that the predictions of quantum mechanics are at odds with a conception of the world where all the interactions are mediated by local mechanisms. The cited reason is the violation of the Bell inequality in cases where measurements are performed on quantum systems of particles that have interacted in the past. Quantum mechanics predicts that the state of the particles in such a system are correlated, a result obtained from considering a thought-experiment often known as EPR. In this thesis, I will argue that the violation of the Bell inequality in EPR forces us to either accept that causes sometimes act both backwards and forwards in time, or give up some widely-held assumptions about causal relations or the role of causal explanations. First, I will present three principles regarding causality that I take be widely accepted. I will then present the background for the claim the quantum mechanics is a non-local theory, and discuss the implications of non-local causal influences in light of the Special Theory of Relativity. One argument against a causal explanation of the EPR-correlations will be discussed, and different models for the causal structure of EPR will be assessed. I will argue that a retrocausal model – models that include instances of retrocausation, where the direction of causation is the opposite of the direction of time – is the only viable option if we want to uphold the three principles presented in chapter 1. I will discuss the plausibility of rejecting one of these principles, and argue that at least one of the can be restricted in a way that still accounts for our commitment to it. Finally, I will assess the non-local models against the retrocausal models, and argue that a retrocausal model offers interpretational advantages over the non-local alternatives.
The most important problems in the philosophy of quantum mechanics are the problem of measurement and the problem of the 'acausal' EPR correlations. It is commonly thought that these problems call for a new interpretation of the quantum theory. I argue that it is possible to construe both problems rather differently, as resulting from a mistaken understanding of scientific theory-application. It then becomes possible to tackle both problems independently of questions of interpretation, by attending carefully to what constitutes a successful application of a scientific theory, and of the quantum theory in particular. In the first part of the Thesis, I argue against a standard conception of scientific theory-application. This standard conception, which is often presupposed in the philosophical discussions of quantum mechanics, takes the applications of a scientific theory to constitute its domain of empirical adequacy. I argue that, on the contrary, a scientific theory can be applied to phenomena that it does not subsume. I present a case study in the history of superconductivity to illustrate and to motivate this claim. In the second part, I argue that the problem of measurement can be construed as the impossibility of applying the quantum theory to measurement interactions. I then argue that Arthur Fine's proposed solution to the measurement problem implicitly abandons the standard conception of application. Finally I look at quantum correlation phenomena. Bas Van Fraassen has claimed that the EPR correlations fit no causal model. The correctness of this claim depends on what probabilistic constraints a causal model is taken to have to satisfy. I argue, following Nancy Cartwright, that Van Fraassen's constraints on common-cause models are too strong; and I describe a direct-cause model that, I urge, constitutes a successful application of the quantum theory to the EPR correlations.
This Ph.D. thesis is about causality in Quantum Mechanics, namely about the possibility to provide a causal explanation for quantum Einstein – Podolsky – Rosen (EPR) correlations.The well-known interpretation of the Bell’s Theorem by Bastian Van Fraassen, who inferred that quantum correlations cannot be embedded in any causal model, compels us to suppose that microscopic nature cannot have a causal structure and that causality is an anthropological concept.However, this interpretation is not commonly accepted and this doctoral thesis is the first general overview of some recent works about causal explanation for EPR correlations. Particularly, it analyses the possible causal explanations for the EPR/Bohm experiments by means of the Hans Reichenbach’s model, by means of backward causation models, and by means of models that imply a direct causal link. In order to do it, it pays particular attention to the Relativistic space-time features and it considers the studies in the History of Philosophy about the link between causal arrow and temporal arrow. Moreover, this work aims to endorse the idea that the best way to explain EPR/Bohm correlations causally is to adopt an indeterministic non-Reichenbachian common cause model, particularly Cartwright’sgeneral forksmodel.My conclusion is that causal models for quantum correlations remain viable, and that there is no contrast between genuinely indeterministic interpretation of Quantum Theory and causal explanation, with the philosophical implication that the Causal Realism is still acceptable.
In his recent work, Michael Redhead (1986, 1987, 1989, 1990) has introduced a condition he calls robustness which, he argues, a relation must satisfy in order to be causal. He has used this condition to argue further that EPR-type correlations are neither the result of a direct causal connection between the correlated events, nor the result of a common cause associated with the source of the particle pairs which feature in these events. Andrew Elby (1992) has used this same condition as a premise in an independent argument for the conclusion that EPR-type correlations cannot be causally explained (except, perhaps, by a nonlocal hidden variable theory). I wish to argue here that robustness is itself too fragile a notion to support such conclusions.
There has been an intense discussion, albeit largely an implicit one, concerning the inference of causal hypotheses from statistical correlations in quantum mechanics ever since John Bell’s first statement of his notorious theorem in 1966. As is well known, its focus has mainly been the so-called Einstein-Podolsky-Rosen (“EPR”) thought experiment, and the ensuing observed correlations in real EPR like experiments. But although implicitly the discussion goes as far back as Bell’s work, it is only in the last two decades that it has become recognizably and explicitly a debate about causal inference in the quantum realm. The bulk of this paper is devoted to a review of three influential arguments in the philosophical literature that aim to show that causal models for the EPR correlations are impossible, due to Bas Van Fraassen, Daniel Hausman and Huw Price. I contend that all these arguments are inconclusive since they contain premises or presuppositions that are false, unwarranted, or at least controversial. Five different common cause models are outlined that seem perfectly viable for the EPR correlations. These models are then employed to illustrate various difficulties with the premises and presuppositions underlying Van Fraassen’s, Hausman’s and Price’s arguments. In all these cases it is argued that the difficulties cut deep against these authors’ own theories of causation and causal inference. My conclusions are that causal models for the EPR correlations remain viable, that philosophical work is still required to assess their relative virtues, and that in any case the mere theoretical conceivability and empirical possibility of these models sheds doubts over Van Fraassen’s, Hausman’s and (important elements in) Price’s theories of causation and causal inference.