Cairns are a kind of public-spirited communication using stones instead of words. Up in the mountains, beyond the tree line, the soil thins out and you may find yourself walking across bare fields where the trail is in danger of being lost. Hikers have long preserved a record of a trail by stacking stones to serve as a marker. Sometimes these towers are beautiful or extravagant, but always they are meant to help a stranger who follows later. You gain nothing for yourself by building or rebuilding a cairn except the knowledge that you are part of civil society where one person pitches in on behalf of others. In that sense cairns are an emblem of the shared responsibility of citizenship. Young people who grow up not knowing about cairns, or at least about the principle behind them, enter adulthood ignorant of one of the central workings of civil society. Walking miles from the nearest town, you see a cairn and know that you are still wrapped in the care of others, including people you will never meet, people who you can never pay or repay. It is not a money economy, but it is essential to life as we know it. If all the cairns have fallen, if we forget to maintain them, then soon we are on our own in a wilderness without hope of an ally, whether we are speaking metaphorically or literally, either one. [Image by Tinelott Wittermans]