Let me make one thing clear: The weeklong vacation on Kauai that my husband and I just returned from was not intended as a yogic retreat. I'm five months pregnant, and so this trip was our last vacation as a twosome. We designed it as a thoroughly secular getaway, the honeymoon we were too busy to take when we got married last year.

We stayed in a condo by Poipu Beach with a view of a brilliant slice of ocean and a lawn as green and groomed as a golf course. Below our balcony, kids tossed Frisbees and kites into a gusty wind. We ate papaya and Haagen-Dazs ice cream and read swollen page-turners like James Michener's "Hawaii" (me) and Neil Stephenson's "Snow Crash" (him). We kayaked up a river past Fern Grotto, where Elvis got married, and went whale-watching on "Captain Andy's" 50-foot catamaran, The Spirit of Kauai.

But once you get on the spiritual path, you just can't help yourself: Just about everything you do runs the risk of turning into a meditation practice. On this trip, it was snorkeling.

For those of you who haven't done it, the ritual goes something like this: You stand knee-deep, and shivering, in the unexpectedly bracing ocean; you put on fins and a mask that you rinse with seawater and spit into, to keep it from fogging up. You stick one end of a plastic tube in your mouth. Then you stagger backward into the water--your fins won't let you walk forward--until you collapse gracelessly into the waves.

One minute your head is out of the water, and all you're conscious of is cold waves, blindingly blue sky, and the feeling that this has all been a terrible and chilly mistake. You'd really rather be up at the beach-side cafe eating a veggie-burger and drinking fresh-squeezed pineapple juice. Then you stick your masked face underwater, and suddenly you're in another world.

Swimming all around you, in what you thought was empty ocean, is a whole other universe of life: brilliantly gaudy fish, blazing pink and yellow, blue and orange. There are big ones and little ones, fat ones and thin ones, striped and spotted and mottled ones. There are trumpet fish, needlefish, triggerfish, butterfly fish, hogfish, and moray eels. There are sea urchins clinging like pin cushions to clumps of coral. And all of them are going about their business, feeding and reproducing, birthing and dying, quite unconcerned with you. I floated like a matronly whale, my pregnant belly a built-in flotation device, my maternity bathing suit billowing around me. Sometimes I'd just bob in one place and watch the different characters coming and going. Other times I'd follow one particular fish as it meandered along the ocean bottom. I trailed one pinktail triggerfish for five or 10 minutes as it wove through the rocks on some mysterious mission of its own, with two smaller fish swimming right behind it. Then I stuck my head out of the waves to find that I had lost my bearings and swum out past the protective reef to the place where the breakers were crashing on the rocks. I quickly paddled back to quieter waters.

All the while, I was aware of the bubble of my belly hanging below me, with my baby floating inside in his own little world. I felt how he was cradled in me, and I was cradled in the ocean, and the ocean and earth held each other in a vast embrace. All of us swam together in the vast belly of space.

As I finally hauled myself back onto the dry sand, it struck me that yoga and meditation are also a kind of snorkeling. Most of the time, I bob around on the surface of my life. But every day, when I get out my mat and my meditation cushion, I put on my psychic snorkel and mask, then dive beneath the surface to see what's there.

As any meditator knows, what you find below the surging surface of your daily life is often a surprise. Thoughts, feelings, and sensations swim about like strange and colorful sea creatures--and one of the shocks of meditation is discovering that they go about their business with wills of their own, paying no heed to the dictates of your splashing and shivering ego.

When you dive below the waves of your conscious mind, you see how much is going on without any input from the nattering little narrator you think of as "you." Your heart beats. Your stomach digests. Your hormones ebb and flow. Your senses absorb and process sounds and images and sensations. New life is conceived and grows inside you. Your body grows old and begins to unravel. Your dreams and desires swim around on their own, gaudy and strange and beautiful.

And your job, as a yogi, is not to chase after any of these phenomena. It's not to control them or change them in any way. It's simply to float and watch and marvel, bowing down to the mystery of it all, letting yourself be as spacious and mysterious as the ocean itself.