Contributions to Quantum Theory: Cause and Effect Still Apply

1. The challenges of quantum mechanics Quantum mechanics introduces us to an unfamiliar and at times puzzling reality. Experimental results suggest that sub-atomic particles can behave in ways that violate classical laws of physics; in quantum entanglement, wave-particle duality, quantum jumps and superposition, to mention only some. A number of interpretations and theories have been offered as attempts to explain such phenomena. Sometimes those interpretations remain openly perplexing, perhaps suggesting that we have to be content with a theory of the world that is deeply counterintuitive. In the extreme case, it might be admitted that the theory makes no sense but is nevertheless true. Philosophers are interested in quantum mechanics but perhaps not primarily because of the challenges it poses for the classical laws of physics. On a more fundamental level, quantum mechanics confronts some of our most basic beliefs about the world. If things can move without passing through intermediate places, or affect one another instantaneously over vast distances, then we must seriously reconsider our assumptions about identity, continuity and causation. If we adopt the naturalistic approach to metaphysics, as more recently defended by Ladyman and Ross (2007), and conclude directly from physical theory to metaphysics, then quantum mechanics seems to challenge some core tenets of our basic ontology. Against such scientific naturalism, we maintain that the physical theory comes already equipped with metaphysical assumptions that we have reasons to reject (see also Andersen and Becker Arenhart 2016). This essay focuses specifically on the notion of causation. There is a line of argument that quantum mechanics is not a causal theory (for one example, see Feynman 1967: 147, though we offer more below). In contrast, we argue that this is not a purely empirical matter but an ontological and conceptual one. To say what causation is would then be a task for philosophy. Certainly, this does not mean that the philosopher can ignore the debates in physics. If a notion of causation has no real application, our ontology might be better off without it. Some do indeed argue that the concept of causation is too confused or ambiguous to be applicable to exact quantum phenomena (Skyrms 1984: 284, Healey 1992: 193). Here, we will first take a closer look at the original debate over causation from classical quantum mechanics. This is because, before accepting quantum mechanics as a counterexample to the central role of causation in science, we should be clear about what it is exactly that is at stake. We then move on to present our preferred theory of causation, based on an ontology of dispositions, and show how this remains unchallenged by arguments from classical quantum mechanics. The dispositional modality plays a crucial part in this argument.

American Journal of Physics, 1963

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Kriterion, 2020

Most philosophers of physics are eliminativists about causation. Following Bertrand Russell's lead, they think that causation is a folk concept that cannot be rationally reconstructed within a worldview informed by contemporary physics. Against this thesis, I argue that physics contributes to shaping the concept of causation, in two ways. 1. Special Relativity is a physical theory that expresses causal constraints. 2. The physical concept of a conserved quantity can be used in the functional reduction of the notion of causation. The empirical part of this reduction makes the hypothesis that the transference of an amount of a conserved quantity is a necessary and sufficient condition for causation. This hypothesis is defended against several objections from physics: that amounts of energy do not possess the appropriate identity conditions required for being able to be transmitted, that there is no universal principle of the conservation of energy in General Relativity, and that there are at least two types of physical systems in which causation does not involve any transference: entangled systems in quantum mechanics and the Aharanov-Bohm effect. In order to show that physics provides means to elaborate the concept of causation it is important to avoid certain misunderstandings. In particular, the claim that there is causation in a physical world does not mean that causation is an additional ingredient of the "furniture" of the world, over and above the ingredients identified by physics.

Synthese, 1963

The Statement "x is the cause of y" is usually taken to mean one of two things - either, in common-sense contexts, that the occurrence of x is a "jointly-sutticient condition" 1 for the occurrence of y, where x and y are distinct events (eg the throwing of a stone and the breaking of a ...

Knowledge and Values, ed. Adam Świeżyński, Wyd. UKSW, Warszawa 2011, pp. 73–94., 2011

The paper revisits the old controversy over causality and determinism and argues, in the first place, that non˗deterministic theories of modern science are largely irrelevant to the philosophical issue of the causality principle. As it seems to be the ‘moral’ of the uncertainty principle, the reason why a deterministic theory cannot be applied to the description of certain physical systems is that it is impossible to capture such properties of the system, which are required by a desired theory. These properties constitute what is called ‘the state’ of a system. However, the notion of a state of a system is relative: it depends on a particular theory which one would like to use to describe given kinds of phenomena. This implies that, even in the case where the desired state of a system is fundamentally impossible to be captured, neither ontological nor epistemological determinism may be excluded. Some following critical considerations are also offered with regard to the claim that uncertainty is “rooted in the things themselves”. The cradle of modern discussions about causality and determinism is, of course, quantum mechanics. Because, as it appears, a judgment on deterministic or non˗deterministic character of a theory can be made only after some interpretation of this theory has been given, the paper briefly reminds some chosen interpretations of quantum mechanics (Schrödinger's, probabilistic, statistical, Copenhagen, and the interpretation of quantum ensembles). Many of such interpretations, offered in the past, have now been rejected, and some gained more credibility than the others. Nonetheless, even the claim that indeterminism is irremovable from the description of the micro-world doesn't imply the rejection of the most general formula of the philosophical causality principle. There is no direct implication between theses of the epistemology of scientific knowledge and those of the ontology of the real world.

arXiv (Cornell University), 2006

It is argued here that the Copenhagen interpretation of quantum mechanics violates the tenets on which both Galileo's and Einstein's theories of relativity are based. It is postulated that the "building blocks" of the universe are not "particles" but are holistic wave-entitities which act and interact with other wave-entities as one would expect from waves. A new approach to model the free electron is presented. It is argued from Coulomb's law that the electromagnetic quantum-field energy is not part of an electric field surrounding the electron, but is localised, so that it is wholly equal to the mass of the electron. It is found that an energy component must also exist along a fourth spatial dimension which could be the origin of the "dark energy" in the universe and which, in turn, should be responsible for "vacuum-fluctuations" as governed by Heisenberg's uncertainty relationship for energy and time. The possible consequences of this approach are analysed and discussed.

Foundations of Physics, 2009

The paper makes a case for there being causation in the form of causal properties or causal structures in the domain of fundamental physics. That case is built in the first place on an interpretation of quantum theory in terms of state reductions so that there really are both entangled states and classical properties, GRW being the most elaborate physical proposal for such an interpretation. I then argue that the interpretation that goes back to Everett can also be read in a causal manner, the splitting of the world being conceivable as a causal process. Finally, I mention that the way in which general relativity theory conceives the metrical field opens up the way for a causal conception of the metrical properties as well.

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Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2018

Causality has never gained the status of a ‘law’ or ‘principle’ in physics. Some recent literature has even popularized the false idea that causality is a notion that should be banned from theory. Such misconception relies on an alleged universality of the reversibility of the laws of physics, based either on the determinism of classical theory, or on the multiverse interpretation of quantum theory, in both cases motivated by mere interpretational requirements for realism of the theory. Here, I will show that a properly defined unambiguous notion of causality is a theorem of quantum theory, which is also a falsifiable proposition of the theory. Such a notion of causality appeared in the literature within the framework of operational probabilistic theories. It is a genuinely theoretical notion, corresponding to establishing a definite partial order among events, in the same way as we do by using the future causal cone on Minkowski space. The notion of causality is logically completel...

Erkenntnis, 2013

I argue that the Causal Markov Condition (CMC) is in principle applicable to the Einstein-Podolsky-Rosen (EPR) correlations. This is in line with my defence in the past of the applicability of the Principle of Common Cause to quantum mechanics. I first review a contrary claim by Dan Hausman and Jim Woodward, who endeavour to preserve the CMC against a possible counterexample by asserting that the conditions for the application of the CMC are not met in the EPR experiment. In their view the CMC is inapplicable to the EPR correlations-i.e. it neither obtains nor fails. The view is grounded upon the non-separability of the quantum state, and the consequent unavailability of interventions. I urge that whether interventions are available in EPR-and why-is a complex and contextual question that does not have a unique or uniform answer. Instead, I argue that different combinations of causal hypotheses under test, and different interpretations of quantum mechanics, will yield different answers to the question. 1. The Principle of Common Cause and the Causal Markov Condition Hans Reichenbach first expressed the Principle of the Common Cause (PCC) as a statement regarding the existence of causes underlying what he called 'improbable coincidences'. As part of his effort to define the direction of time in relation with that of open conjunctive forks, Reichenbach first of all asserted that: "if an improbable coincidence has occurred, there must be a common cause". Without any further stipulation, and without any definition of a common cause, this statement remains essentially a postulate. It stipulates the existence of such a cause when a coincidence between two token events has occurred that is improbable in the sense that it is both lawlike and unexpected (i.e. it arises out of a correlation between the types, and it does not result from any causal relation between the tokens), then there must be some underlying event that causally explains away the coincidence. Let us refer to this general statement, which forms the first part of the PCC, as the postulate of the common cause (Suárez, 2007). The PCC is not exhausted by the postulate, however, but it is typically combined with a specific criterion of the common cause providing a characterisation of common causes-and an essentially methodological as opposed to metaphysical guide to causal inference from statistics. Reichenbach's own criterion was the very well known screening off condition, which took common causes to necessarily screen off their joint effects from each other. We say that c screens off a from b if and only if: € P a b & c