Harry Collins and Robert Evans have in their book “Rethinking Expertise” (2007) made an attempt to categorise differend types of knowledge. The periodic table of expertise that they have created is based on the idea of tacit knowledge, and names and places the different kinds of expertise. The term `tacit knowledge’ was used my Michael Polanyi to refer to those things we can do without being able to explain how. Individuals acquire expertise through being members of expert groups. It takes much time and effort to socialize into these groups. A large part of the knowledge acquired can not be explained formally. It is knowledge that is embedded in language and society. Tacit knowledge is an important part of all kind of expertises. Collins and Evans argue for a realist theory of expertise independent of the social attribution of expertise. They are critisizing the STS approach of describing the social attribution of knowledge without taking a stand (the importance of symmetry in STS). One should be able to assess who has knowledge and who not. They call it “The third way”. Still they acknowledge that the boundaries of knowledge can be difficult to draw in a strict way in real life. It is a first attempt to categorize different kinds of knowledge. A broad definition of expertise could be “to know what you are talking about”, there is no difference between knowledge and expertise. Expertise is in culture and in practice, and is found more in practice than in books. It is about doing, performing and talking. (H. Collins, R. Evans, 2007)

Interactional Expertise is fluency in the technical language associated with a specialism. The ability to expertly converse about expertise without being able to practice it. It is learned through linguistic socialisation and achieved by spending enough time with practitioners. Interactional expertise is an expertise between informal and formal knowledge – between books and practice.

To have Contributory Expertise is to know enough to contribute to the development of a specific expertise. A deep understanding. It is the “real” knowledge, the practice. (H. Collins, R. Evans, 2007)

(MH, 2010)

Could it be argued that in the design of the open international competition for architects for a design of the Norwegian Opera House (1999), there was imbedded a demand for an expertise which was suited to produce a Nordic if not even a Norwegian winner?

All of the architects participating in the competition posessed approximately the same contributory expertise as the competition only was open to architects with an approved examination under the EU’s architect directive. This means that Norwegian participants had to be civil architects or members of NAL. Foreign participants inside the EEA area had to document that they have qualifications equivalent to the European Union’s Directive. Other foreign participants had to document equivalent qualifications. However, the tacit knowledge achieved through the embedment in the Nordic/Norwegian culture of strong social democratic values, as well as interactional expertise towards the involved actors put Snøhetta in a special position probably along with the other Norwegian contributors to the competition.

It could seem that the international approach towards the competition was to a large extent encouraged and forced by the EEA  Agreement and NAL. The strong focus on the Norwegian language in the jury and also the missing internationality of the jury members, gives Snøhetta and other Norwegian/Nordic architects the advantage of tacit knowledge within the Nordic culture. It gives them an expertise which communicates with the expertise of the jury members. Snøhetta and the other Norwegian contributors were in addition closely connected to NAL through the membership of employed architects. Snøhetta posessed additional interactional expertise achieved through the collaboration with Statsbygg on the exposition “Ny opera i Bjørvika”.