Constructor theory

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As formally introduced by Physicists David Deutsch in 2012, Constructor theory "seeks to express all fundamental scientific theories in terms of a dichotomy between possible and impossible physical transformations – those that can be caused to happen and those that cannot."[1]


Constructor Theory recognises that "the empirical content of a scientific theory is in what it forbids." This respects the way scientific principles (e.g. of the conservation of energy) allow us to rule conceivable transformations (counterfactuals) as either conceivable or as simply incompatible with what we understand about how the universe works.

The theory is being brought into Naturalising Sense-Making through Substrate-Independence Theory.

Key Concepts

The language of Constructor Theory breaks significantly with traditional physics. Key concepts include:

Tasks and Counterfactuals

At the heart of Constructor Theory we find Tasks. These are possible (or impossible) physical transformations. A counterfactual is simply an imagined physical transformation (specifying a task which would need to be completed).


For Physicists David Deutsch and Chiara Marletto, constructors are identified functionally by their capacity for catalysing some form of transformation and of remaining able to cause new (further) transformations.


In Constructor Theory, anything which can be transformed features as substrate. Any task must, by definition, transform some substrate from a prior state to a transformed state. Specifying any task therefore requires identification of some input attribute of a substrate and some output attribute of a substrate.

Constructor Theory of Information

David Deutsch and Chiara Marletto talk of knowledge as an "abstract constructor." For discussion see The Constructor Theory of Information.

The Constructor Theory of Probability

See The Constructor Theory of Probability.

The Constructor Theory of Life

See The Constructor Theory of Life

Constructor Theory of Cognition

In cognitive context, the constructor is a subject who thinks. A subject for example can simply think, or he can make a choice or give an answer: all these situations cause a transition of belief. In other situations, the interaction is with an external system, also called environment, like for example another subject or an object. The subject is able to perform again cognitive processes leaving unchanged such ability, of course with human limits imposed by attention and physical resources.

— Riccardo Franco, First steps to a constructor theory of cognition, arXiv:1904.09829 [cs.AI]

See First steps to a constructor theory of cognition.


Deutsch, D. Constructor theory. Synthese 190, 4331–4359 (2013). The Constructor Theory of Life

Method card material

This material will be extracted for the method cards

Possible symbols or illustrations

Front page description

Phase shift

Back of card summary

A process or activity designed to change the nature of interactions (constraints) over time to shift something between Cynefin domains. For example, a method to reduce options to allow linear iteration would be a shift from Complex to liminal complex-complicated. When mapping constraints, we will find examples that have emerged over the years. They may be formal processes or softer things like rituals.

How can it be used?

for diagnosis

for analysis/understanding

for intervention

Method Properties - Ratings

Represented by symbols - interpretation/voting scales are:

COST & RESOURCES: How resource-intensive is the Method in terms of materials and tools required, and thus costs?

  1. Requires only common office equipment (eg paper and pens)
  2. Requires simple facilitation materials (special hexies, printouts, whiteboards etc)
  3. Requires some inexpensive but specific tools and materials
  4. Requires moderate investment in tools or software to apply
  5. Requires significant investment in software or other specialist tools

COMPLEX FACILITATION SKILL: How much training and skill in complex facilitation does the Method require?

  1. No complex facilitation experience is required
  2. Some complex facilitation experience needed - practice in a safe space
  3. Should be mentored while developing complex facilitation skill
  4. Requires Mentoring until proven, familiarity with theory critical
  5. Advanced, requires deep knowledge of theory and experience

ENGAGEMENT GRADIENT: How challenging is engagement of participants into the Method likely to be?

  1. Ad hoc technique - can be used in multiple contexts with relative ease
  2. Requires time commitment but overall, engaging and not difficult to achieve
  3. Mild uncertainty or discomfort, may need work to keep people engaged
  4. Indirect/ambiguous method, requires engagement through sustained levels of uncertainty
  5. Challenging method – may incur resistance if people expect a more traditional approach