Barthes writes: the binary classification of concepts seems frequent in structural thought, as if the metalanguage of the linguist reproduced, like a mirror, the binary structure of the system it is describing. However, on the level of the discourse, it is usually a tripartite classification of concepts which operates. Here are some examples from historiography:
The sources of England’s wealth must be sought in i) her extensive domestic circulation of goods, ii) in her advanced division of labour, and iii) in the superiority of her machines.
Louis Simond 1812
So far the history of Europe has been dominated by the three great forces of i) Hellenic civilisation, ii) the Roman empire, iii) the Christian religion, the first two clearly interlinked, but the last deriving from the east and challenging at many crucial points the i) conduct, ii) beliefs and iii) interests of the ancient world.
H.A.L. Fisher 1935
Industrialization prospers when it is introduced to low income areas – as can be seen today by looking at i) South Korea, ii) Hong Kong and iii) Singapore.
This tripartite ordering of concepts has a certain kind of natural symmetry about it (Father Son, Holy Ghost; Centre, Left and Right). However, it risks at the same time imposing an artificial structure on the world, risks oversimplifying it, tidying it up. Were there really only three sources of English wealth in the 19th century? Were there really only three forces which dominated European history up until the Germanic invasions of the 3rd Century? Are there really only three examples of areas with rapid industrialisation? Or have these trinities been selected by the discourse in its drive for explicatory convenience, in its search for rhetorical order? What criteria influence their selection? What does this structural imperative of the discourse leave out, and (how) does it effect the way we see the world?
We see what we bring. Henry Adams.