To celebrate my son’s very first day of preschool, as well as my daughter’s first Monday in fourth grade, this morning I listened to an interview with geophysicist Xavier Le Pichon from Krista Tippett’s website “On Being.”

If you’re not familiar with the website or the radio show of the same name, I highly recommend both. Formerly known as Speaking of Faith,  Tippett’s program features interviews with spiritual leaders, as well as scientists, artists and politicians who offer valuable perspective on the life of the spirit.

Entitled Fragility and the Evolution of Humanity, Pichon’s interview reveals the insights of a man who – as a pioneer in the field of Plate Tectonics – has given much thought to the role that fragility and weakness play in both geological and human evolution.

His main thesis is that – just as the earth’s surface reached its current configuration when stresses on weak spots below the surface caused land to shift and create the continental masses – humanity also evolved, and can only continue to evolve, through a fluid relationship between the weak and the strong.

As early as the Neolithic Age, he points out, our ancestors were caring for the disabled  – not leaving them to die, as would be expected if only the fittest could survive.

Drawing on such history, as well as  personal experiences in communities caring for the poor  and the sick, Pichon has observed that a community which is flexible enough to accommodate the weak will evolve, while a community unable or unwilling to do so will only be changed through crisis and revolution.

Humanity at its best, Le Pichon concludes,  is not something we are born with: nor is it something that is arrived at and done with. It is a quality that must be nurtured – individually and socially – throughout a lifetime and throughout history.

This rich interview with Le Pichon offers a  profound teaching that can be carried into any life: whether the weakness we are meant to accommodate and care for is our children’s, our parents’, our spouse’s, our friends’ – or our own.