Rossella Lupacchini is Associate Professor of philosophy of science at the University of Bologna. Her research has been primarily concerned with the philosophy of physics and the philosophy of mathematics. Her interests extend over various aspects of mathematical forms, with a focus on the role played by complex numbers in quantum theory and its computational structures.

John Stillwell is Professor of Mathematics at the University of San Francisco, where he has been since 2002. Prior to that he was at Monash University in Australia from 1970, following a Ph.D. at MIT. During his career his interests have ranged from logic to geometry, with a constant interest in the history of mathematics.

Ulrich Majer is Extraordinary Professor at the *Philosophisches Seminar* of the University of Göttingen. His research interests include the philosophy of mathematics and the natural sciences. He is particularly interested in the epistemology of Husserl and Kant, as well as in nineteenth and twentieth century philosophy. Under the auspices of the *Deutscher Forschungsgesellschaft*, he is editing David Hilbert's posthumous writings on the foundations of mathematics and the natural sciences.

Miklós Rédei is professor in the Department of Philosophy, Logic and scientific Method of the London School of Economics. His field of research is philosophy of modern physics, especially foundational problems of quantum mechanics and quantum field theory. He is the author of the book *Quantum Logic in Algebraic Approach* (Kluwer, 1998), and editor of *John von Neumann: Selected Letters* (American Mathematical Society, 2005). **[End Page 161]** He also has published on general philosophy of science. For more details see his webpage: http://phil.elte.hu/redei/

Chiara Marletto is a quantum physicist, doing research for a DPhil in Quantum Computing at the Mathematical Institute, University of Oxford. Her latest research has been focused on the nature of information and on its status within physics. One of the issues she is currently investigating, together with David Deutsch, is how to apply the recently proposed Constructor Theory to provide a fundamental theory of information within Physics. Another line of her research is about how to find effective ways to transfer and copy information from one quantum medium to another—a task on which Quantum Theory imposes strict constraints. This has recently led her to address the deep problem of how the logic of self-replication can be consistent with Quantum Theory.

Mario Rasetti is Professor Emeritus of Theoretical Physics at the Politecnico (technical university), and President of the ISI Foundation in Torino, Italy. He studied in Italy and Sweden, and spent a large fraction of his professional life in the United States. His contributions to science were mostly in theoretical and mathematical physics, mathematics, information science and complexity science: solid state, statistical mechanics, theory of non-linear dynamical systems and chaos, quantum mechanics and quantum optics, quantization, quantum information and computation, topological quantum field theory, topological methods in data science, knot theory, quantum and super algebras.

Vito Michele Abrusci is Full Professor of Logic at the University "Roma Tre", where he heads the research group in "Logic and geometry of Cognition". He has been Dean of the "Facoltà di Lettere e Filosofia" at the University "Roma Tre" and President of the Italian Society for Logic and Philosphy of Science. His main scientific interests are linear logic and its developments, proof theory, history and philosophy of logic.

Wilfried Sieg is Patrick Suppes professor of philosophy at Carnegie Mellon University and a fellow of the American Academy of Arts and Sciences. He joined Carnegie Mellon's faculty in 1985 as a founding member of the University's Philosophy Department and served as its Head from 1994 to 2005. He is internationally known for his mathematical work in proof and computation theory, historical work on modern logic and mathematics, and philosophical essays on the nature of mathematics. A collection of essays joining the three aspects of his research was published under the title *Hilbert's Programs and Beyond* (Oxford University Press, 2013). **[End Page 162]**