Even our most successful and advanced theories of foundational physics – general relativity and quantum theory – have so far been unable to give a complete account of the universe. Meanwhile, philosophy continues to wrestle with questions of knowledge and consciousness. Might constructor theory provide an answer to both?

Constructor theory is a relatively nascent idea in fundamental physics that proposes to underlie all other currently known theories, not to mention those yet to be known, and to solve problems across a host of fields in science and beyond.

Logan Chipkin joins Oxford physicist and constructor theorist Chiara Marletto to discuss what constructor theory is, how it might point the way to a successor to quantum theory, and how it might allow physics to tackle some of philosophy’s most perplexing puzzles.

Chipkin: What is constructor theory?

Marletto: Constructor Theory was originally proposed by David Deutsch in 2012. The program was to try to recast the whole of physics in different terms. Instead of using the ‘dynamical laws + initial conditions’ approach, David suggested an approach which is rooted in the quantum theory of computation, but extended to the rest of physics. The approach is to use statements about what tasks are forbidden/impossible, and what tasks are possible, and why. When we started working together we realized that the theory actually had a much wider applicability than it had originally seemed. I came in by applying constructor theory to various open problems in quantum information, in quantum thermodynamics, in the foundations of quantum physics, and so on.