Abstract
The aim of this paper is to refute the hypothesis that the observer’s consciousness is necessary in the quantum mechanics measurement process. In order to achieve our target, we propose and investigate a variation of the Schrödinger’s cat thought experiment called “DAP”, short for “Dead-Alive Physicist”, in which a human being replaces the cat. This strategy enables us to logically disprove the consistency of the above hypothesis, and to oblige its supporters either to be trapped in solipsism or to rely on an alternative interpretation of quantum mechanics in which the conscious observer plays the sole role of acknowledging the experimental results. Our analysis hence provides support to clarify the relationship between the observer and the objects of her/his experimental observation; this and a few other implications are discussed in the fourth section and in the conclusions.
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13 April 2021
A Correction to this paper has been published: https://doi.org/10.1007/s10701-021-00451-y
Notes
There are two main theses arguing that consciousness and quantum mechanical measurement are connected to each other: one thesis (von Neumann, London and Bauer, Wigner, Stapp; see Refs 3,4,5 and 22) holds that the observer's consciousness causes the collapse of the wave function, thus claiming to complete the quantum-to-classical transition, while the other thesis (Penrose; Penrose and Hameroff; see Refs [18, 20, 21]) aims at demonstrating the opposite, i.e. that consciousness emerges from the so called "Orchestrated Objective Reduction".
We don't know how consciousness works and do not have any idea of its nature. Nonetheless we are undoubtedly certain to possess it as the intimate and the most familiar of our experiences. In general, consciousness is defined as the faculty that allows a human subject to be aware of her/his self and of her/his mental activities, as well as the faculty to learn from the perception of external events to which these activities are directed. Leading contemporary scientists in the field have tried to lay the foundations for a science of consciousness, but none of them has yet been able to boast a promising theoretical approach. The Australian philosopher of the mind David J. Chalmers argues that, to open a window towards the understanding of consciousness, it would be required to solve the so called "difficult problem", consisting in finding a correlation between the functional mechanisms engendered by the neural activity of the brain and conscious experience, i.e. the phenomenon that allows the owner of that brain to feel specific effects in the first person.
In such a mechanism a battery is supplying electric power.
This rule, introduced by Max Born in 1926, states that in QM experiments the probability of obtaining any possible outcome, after a measurement/observation, is equal to the square of the corresponding probability amplitude.
Wigner's friend, here called “F”, is a physicist left alone inside a laboratory with the task of checking attentively whether or not a detector has emitted a flash (has registered the arrival of a photon or not). Wigner is waiting outside and suspects that F (as well as all other human beings) may have weird perceptions and be in the superposition of macroscopically distinct states|F has perceived a flash > + |F has not perceived a flash > . Finally, Wigner enters the lab and asks F whether or not he perceived a flash. His reply (yes or no) should remove any doubt as to whether the wave-function collapse has occurred. However, Wigner will question whether it is acceptable or not to establish that the collapse into one only of the two possible alternatives is determined by his action (his request and reception of an unambiguous answer). He poses this question since his initial way of interpreting the state of the system gives rise to a rather embarrassing paradox, from which he has three possible ways of escape: (1) accept a relative form of solipsism, in the sense that he believes to be, among all living creatures, the only one who has unambiguous perceptions, (2) assume that QM is an incomplete theory, (3) assume that QM is not applicable to human beings; he refutes solipsism and, being a firm supporter of QM completeness, opts for the last solution, assuming that there are beings, at least human beings, endowed with consciousness that constitutes an ultimate reality and plays an active role in determining the measurement process by rules that are not susceptible to scientific description.
The question of causality is problematic, since it requires a distinction between the subjective and the objective aspects of this concept. Causality entails another (arguable) question called "cause and effect simultaneity", which has been discussed and investigated in depth by several philosophers, such as I. Kant, D. Hume, G.W. Leibniz and, recently, by Donald Gillies, Jay F. Rosenberg, Sylvain Bromberger et al.; for a detailed understanding see Buzzoni M.: The Agency Theory of Causality, Anthropomorphism, and Simultaneity, Sect. 6, published online: 29 Jan 2015, https://doi.org/10.1080/02698595.2014.979668.
There are two different forms of solipsism: one is described in note 2 as a relative solipsism, the other (associated to an inflexible belief in the CCCH) would lead to an absolute solipsism, that is to say "I believe to be the only thinking entity, while an external reality (including my body), being a product of my mind, does not exist".
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Acknowledgments
Our special gratitude goes to the late Giancarlo Ghirardi Professor Emeritus of Physics, Università di Trieste, Carlo Rovelli Professor of Physics, Université de Aix-Marseille, Art Hobson Professor Emeritus of Physics, University of Arkansas, Gianni Battimelli Professor of Physics, Università La Sapienza di Roma, Enrico Marchetti, Professor of Economic Policy, Università degli Studi di Napoli Parthenope, and Lorenzo Stella Professor of Physical Chemistry, Università di Roma 2, for reading and commenting on the manuscript. Finally, we have to thank Susan Beswick for her scrupulous control of the English language of the text.
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CR devised the thought experiment, both CR and BRS wrote the article.
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Bruno Raffaele Stella—Currently retired from Dipartimento di Fisica, Università Roma Tre and INFN Roma Tre, Rome, Italy.
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Roselli, C., Stella, B.R. The Dead-Alive Physicist Experiment: A Case-Study Against the Hypothesis that Consciousness Causes the Wave-Function Collapse in the Quantum Mechanical Measurement Process. Found Phys 51, 21 (2021). https://doi.org/10.1007/s10701-021-00427-y
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DOI: https://doi.org/10.1007/s10701-021-00427-y