Pietro Donà^*

• Aix-Marseille Université, Université de Toulon, CNRS, CPT, Marseille, France

Hal M. Haggard^†

• Physics Program, Bard College, 30 Campus Road, Annandale-on-Hudson, New York 12504, USA

Carlo Rovelli^‡

• Center for Space, Time and the Quantum, 13288 Marseille, France; Department of Philosophy and Rotman Institute, Western University, London N6A 3K7, Ontario, Canada; Aix-Marseille Université, Université de Toulon, CNRS, CPT, Marseille, France; and Perimeter Institute, 31 Caroline Street North, Waterloo N2L 2Y5, Ontario, Canada

Francesca Vidotto^§

• Department of Physics & Astronomy, Western University, London N6A 3K7, Ontario, Canada and Department of Philosophy and Rotman Institute, Western University, London N6A 3K7, Ontario, Canada

• ^*pietro.dona@cpt.univ-mrs.fr
• ^†hhaggard@bard.edu
• ^‡crovelli@uwo.ca
• ^§fvidotto@uwo.ca