Thinking the unthinkable

Tomas Petricek, Alan Turing Institute | | @tomaspetricek

Founding of natural sciences

A story about incommensurability

Founding of natural sciences

The Order of Things
Michael Foucault (1966)

  • Ulisse Aldrovandi (1522 - 1605)
  • Comte de Buffon (1707 - 1788)

Founding of natural sciences

Buffon was [astonished by Aldrovandi's] mixture of exact descriptions, reported quotations, fables, remarks dealing indifferently with an animal’s anatomy, its use in heraldry, its habitat, its mythological values or the uses to which it could be put in medicine or magic.


Two theories do not share a basis that would
allow evaluating them using a common metric.

Appears in multiple forms

  • Foucault's episteme
  • Kuhn's paradigms
  • Lakatos' research programmes
  • Polanyi's personal knowledge

Hidden assumptions in programming

Episteme, paradigms & research programmes

Programming is error-prone. It is even worse when programming a quantum computer (...) because human intuition is much better adapted to the classical world than to the quantum world.

How can we build automatic tools for verifying correctness of quantum programs? A logic for verification of both partial correctness and total correctness of quantum programs was developed (...).


Algol research programme

One of the goals of the Algol research programme was to utilize the resources of logic to increase the confidence that it was possible to have in the correctness of a program.

Science of Operations
Mark Priestley (2012)

Episteme, paradigm or research programme

Change what questions we ask

What does the PL community assume?

What does the PPIG community assume?

Mathematization of computer science

The rise of theoretical computer science was anything but inevitable. (...) Advocates of theoretical computer science pursued a strategy that served them well within the university, but increasingly alienated them from their colleagues in the industry.

The Computer Boys Take Over
Nathan Ensmenger (2012)

Thinking the unthinkable

What else could programming research be?

Foucalt's classical episteme

Museums and encyclopedias

Collections of species as they are

Organized according to taxonomy

Programming and sample species?

Common Law is founded on precedent. (...) Courts [today] will follow the example of other courts which have decided similar cases in the past.

This procedure recognizes the principle (...) that practical wisdom is more truly embodied in action than expressed in rules of action.

Personal Knowledge
Michael Polanyi (1958)

Renaissance episteme

Resemblances between signs

Across all areas of knowledge

Programming with signs?

Resemblances between signs

Animal's anatomy, its habitat and the
uses to which it could be put in magic.

Programming with signs?

Resemblances between signs

Programming tool's theory and the
uses to which it could be put in practice.

Programming with signs?

Stories, metaphors and analogies bridge the
boundaries across different forms of knowledge

If a subject does not permit exactness,
it is not sufficient to be exact about something else.

Personal Knowledge, Michael Polanyi (1958)


Animal's anatomy and its uses in magic


Programming tool anatomy its uses in magic


During the 18th century the French Academy of Sciences
stubbornly denied the evidence for the fall of meteorites.

We no longer consider falling of meteorites to be incompatible with the scientific world view. But other doubts, which we now sustain as reasonable have only our beliefs to warrant them.

More information

More philosophy of science

Current PPIG paper draft

What I'm also working on :-) | | @tomaspetricek