"Life lessons from swimming permeate the foundations of our society, with references in everything from the Bible to rock music. In a fourteenth-century illuminated manuscript accompanying Psalm 69, King David — naked, a crown atop his curls — swims through an ocean of blue waves ('the deep waters' of despair), praying for salvation. The Talmud says that a Jewish father must do several things for his son: circumcise him, teach him Torah, find him a wife, teach him a trade. And teach him how to swim. According to Rabbi Anne Ebersman, director of Jewish programming at New York's Abraham Joshua Heschel School, that can be interpreted two ways: First, to prevent drowning in a world where trade depended on sea travel. 'Ships were dangerous,' she explains to me. 'And probably there were stories about drowning. But swimming can also be seen more metaphorically,' she goes on, 'how to take care of yourself, knowing that you can master something by yourself. So it's a basic skill to get through life and also a metaphor to get through life.' The same point is made by an advisor to Mohammed and one of the major voices of Islam, Umar Ibn al-Khattab. 'Teach your children swimming, archery and horse-riding,' he says, a directive often interpreted as serving the soul as well as the body.

"More contemporary moral guidance comes from the bighearted blue fish named Dory in the movie Finding Nemo. When Marlin, the clownfish, gets the grumps, Dory grabs his fin, wriggles onward, and sings, 'When life gets you down, do you wanna know what you've gotta do? Just keep swimming, swimming, swimming.' "