This is not a fifth lens, only a map of where the four genuinely disagree.
The sharpest dispute is between the consensus and revisionist readings over whether Costa Rica’s early equality was real or retrospective. Both agree the colonial economy was poor and the coffee boom came in the 1830s; they disagree on what those facts mean, one treating them as evidence of a genuinely broad-based smallholding society, the other as raw material later shaped into a flattering national myth by an elite that was never as absent as the myth implies.
The clearest case of rival explanations for a single event is the 1949 abolition of the army. The cultural and consensus lenses treat it as the culmination of a long civilian, reformist tradition — a moral and political achievement in its own right. The revisionist and economic lenses treat the same act more instrumentally: a fiscal reallocation and a way of demobilizing a defeated faction’s military option, whose peaceful, principled reputation was substantially built up after the fact.
All four agree on one thing without qualification: Costa Rica diverged sharply from the militarized, land-concentrated path many of its neighbors followed across the twentieth century. They part entirely on why — geography and a poor colonial inheritance (economic lens), a genuinely distinct civic culture (cultural lens), authentic bottom-up democratic achievement (consensus), or elite strategy dressed in democratic language (revisionist).
Reference status: all eight works cited above — Molina & Palmer (2007); Bell (1971); Yashar (1997); Stone (1975); Samper (1990); Gudmundson (1986); Winson (1989); Edelman (1999) — were independently verified to exist, with authorship, title, and publication year confirmed against publisher, library, or academic-review records, before being cited here. Stone’s thesis of an unbroken conquistador-descended oligarchy is itself a contested minority position within Costa Rican historiography, presented above as a challenge to the mainstream account, not as settled fact.