Zenith Grant Awardee

Howard Wiseman

Griffith University

Co-Investigators

Antoine Tilloy, Max-Planck-Institut fur Quantenoptik

Project Title

Quantum and consciousness: paths to experiment, and implications for interpretations

Project Summary

Quantum theory seems to work perfectly for predicting the outcomes of laboratory experiments, but at the expense of dividing the world into an observer (experimenter) and the observed (system). In 1961, Eugene Wigner asked: what happens when one conscious observer treats another (his ‘friend’) as a system? Wigner concluded that quantum theory must break down in this situation, but he did not formulate his argument precisely, nor suggest any way his conclusion could be tested experimentally. Recently, there has been a surge of interest in doing both these things, with arguably the most powerful result being developed by two of us. However, our work raises many further questions which we aim to answer in this project. First, what sort of ‘friends’ could be incorporated into experiments of increasing complexity, to what extent they would be conscious, and exactly what would each experiment prove? Second, if these experiments are performed, what will that mean for the various proposals that have been made for making sense of the system–observer divide in quantum theory? Third, what new ideas for making sense of quantum theory are suggested by these results? Answering these will reveal much about consciousness and the physical world.

Technical Abstract

Interest in “Wigner’s friend”––especially the extended scenario with entangled ‘friends’ whose state can be manipulated––has resurged recently amongst quantum physicists and philosophers. The starting point for our proposal is the new no-go theorem proven by two of us, that for experimentalists (‘Wigners’) with sufficient power to manipulate the quantum state of their friends, the predictions of standard quantum mechanics contradict the conjunction of three metaphysical assumptions: Absoluteness of Observed Events, Locality, and No-Superdeterminism. This result suggests new questions about Consciousness in the Physical World that we will address through three aims. The first aim is to adapt our theorem so that it directly addresses the issue of consciousness, with all the technical, philosophical, and experimental ramifications of doing so. The second aim is to consider the implications of the new theorem (or, as we expect, theorems, given multiple possible technical and experimental scenarios) when formulated in terms of consciousness, for all the major existing versions of quantum mechanics. The third aim is to explore whether these results suggests new versions of quantum mechanics, in particular those that expressly refer to consciousness, that resolve at least some of the no-go theorems in a different way from all previous versions.