Arch and Resilience

An architecture professor shared this quote with us during a structural engineering seminar back at École des Ponts.

Once the final stone is in place (the "keystone"), an arch stands on its own. No need for nails, concrete, or supports. Not only does it stand, but it can also bear weight. Hence this quote from Primo Levi:

"Why, I asked myself, doesn't the arch collapse, when it has no support? It holds, I answered, because all the stones want to fall in the same motion. This thought brought me great comfort, and I keep it with me for the decisive moment, hoping that I, too, will know how to hold on when everything inside me wants to collapse."
– Primo Levi, The Truce

An unexpected application of the stress tensor to human resilience.