Constructor Theory of Information

The purpose of this project is to discover the single underlying explanation for all distinctive properties of information in Physics and beyond, which is at once the root of both the familiar properties of information, such as transcending specific embodiments, and its apparently paradoxical quantum-mechanical ones.

Our main innovative tool for addressing this is Constructor Theory, recently proposed by David Deutsch. This theory expresses all scientific theories in terms of a dichotomy between possible and impossible physical transformations - an audacious departure from existing fundamental physics (whose dichotomy is between what happens and what does not, given initial conditions).

Applying the constructor-theoretic approach to information theory, we have established the result that a simple constructor-theoretic property of the laws of quantum physics implies all the disparate features that distinguish quantum information from classical, thus revealing the hitherto mysterious connection between them. (Deutsch and Marletto, 2014)

Building on these results (Marletto, 2015), we have also addressed the issues of whether and how certain properties of living entities, such as the ability to self-reproduce and replicate, can be possible under no-design laws of physics. One shows that they can, provided that those laws allow, in addition to enough resources, information media, as characterised in the constructor theory of information.

Our work is now focussed on two projects,“Constructor Theory of Testability” and “Constructor Theory of Probability”. The latter generalises the well-known arguments to show how the Born Rule can emerge in unitary quantum mechanics, un-augmented with additional probabilistic postulates. Our constructor-theoretic generalisation depends on fewer and much simpler axioms, which are better motivated physically and are now expressed in an information-theoretic form. The Constructor Theory of Testability uses this argument to show that Unitary Quantum Theory is testable against rival theories. A new strand of research in the direction of investigating the properties of superinformation media has also emerged, using the information-theoretic tools of constructor theory to explore the information-theoretic properties of quantum media – chiefly, the possibility of teleportation  – regarding quantum systems as a special case of superinformation media.