Fish gotta swim. Birds gotta fly. What doesn't gotta happen is what an Alsatian man named Rémy Bricka likes to do—walk on water. In March  Bricka began what he hoped would be a walk, on buoyant ski-length footgear, across the Pacific Ocean. Because it is there, presumably.
Bricka already holds a place in the Guinness World Records by virtue of a previous tromp across the Atlantic in 1988. Normal journalistic practice would include an attempt to reach Bricka for a first-person account. That idea ground to a halt upon contemplation of the words of linguistic philosopher Ludwig Wittgenstein: “If a lion could talk, we would not understand it.”
Just as the uniquely leonine experience imposes a worldview that would make meaningful communication impossible, the Bricka experience probably placed him beyond my comprehension. My father really is a carpenter who really is named Joseph, but any messiah complex I may have is too puny to help me figure out why somebody wants to walk on water. And I haven't even mentioned that Bricka takes leave from his job as a one-man band to take his walks.
Actually, lots of guys walk on water all the time. They are called hockey players. But restricting the discussion to water in the liquid phase, your average human makes a poor pond pedestrian. Bricka's passion, however, made me wonder about the creatures—none great, all small—that truly can keep their feet above water.
Such animals exploit various physical principles to stay afloat. Biologist Robert B. Suter has studied one such critter, the aptly named fishing spider. He explains that its legs produce tiny dimples on the water thanks to surface tension, the slight attraction of water molecules to one another that becomes a Brobdingnagian factor at Lilliputian scales. “What makes the dimple stay intact is surface tension, and a lot of the force that holds the spider up is surface tension,” Suter says. Add the water's drag, and when the spider drives a leg against its dimple, voilà, it's walking.
Although there are characteristics of rowing involved here, and despite the fact that the dimples also act as hulls and impart an additional slight buoyancy, this process seems much like the kind of walking with which we humans are familiar. A leg pushes against a surface that pushes back. So while I hate to burst his bubble, Bricka's walks seem misclassified. He is actually a conventional sailor sailing unconventional vessels: two boats that happen to fit on his feet.
On the other hand, Bricka could become a genuine water walker through modified gear that would allow surface tension to work its magic. He needs to get edgier, the edge in question being where water, air and foot meet and where surface tension does its stuff. Calculations, for freshwater, by Mark W. Denny of Stanford University show that a 110-pound person could walk on water using footwear with a total perimeter of about 6.7 kilometers (4.2 miles). Laces surely sold separately. A bigger challenge than walking the Pacific would then be wearing both shoes at the same time.
An alternative noted by Steven Vogel of Duke University is severe weight reduction. Assuming Bricka wears about a size 9, his feet alone would support him on the water if he managed to slim down to about five grams, an accomplishment that would render the ensuing Pacific walk a mere footnote.
All this advice comes too late. Bricka's march on the sea, which he had estimated would take six months, was over almost before he could wave good-bye. On day one, a storm wrecked the catamaran he towed behind him, costing him food, supplies and bed. And so his mare trek came to an end. Fortunately, he escaped unscathed and continues to walk among us. Because he didn't sink. Like a bricka.