A wheel is important because by turning it turns other things too. An axle is just as important because otherwise, the wheel would be, well, freewheeling, going everywhere and nowhere. Without a linchpin, however, neither the wheel nor the axle would accomplish anything. The wheel may turn on the axle, but not for long.
There are linchpins in any system which requires stability and continuity. There are linchpins in modern organisations where the division of learning and labour keeps going up. The marketing guru Seth Godin has a thing or two to say about those linchpins.
There are also linchpins we never think of. Like the cultural-survival linchpin. There were many occasions in the history of Western Europe where the transmission of the past – the transmission of past knowledge, art, skills, ways of being, speaking, behaving – was threatened to the point that the channeling of past cultural capital to future generations would shut down altogether. This happened when the Late Antiquity (3rd-6th century AD) became very late and the early Middle Ages too early.
Authors like Boethius, Cassiodorus and Isidore of Seville scrambled to bundle up the written culture of the ancient world in a way that could be transmitted to a radically different future. In Boethius’ ‘Consolation of philosophy’ (written around 524 AD), Cassiodorus’ Institutions of divine and secular readings (composed in the 550s) and Isidore’s Etymologies (published in the early 600s AD), the hiatus menacing the survival of classical culture was more or less averted. In these works (and several others), continuity was rescued by a band of cultural linchpins. They also became some of the most influential figures of the emerging medieval world, shaping its culture decisively.