It’s a spring Sunday morning in Ashland. I’m sitting in dappled shade along Hamilton Creek, keeping half an eye on my son and his friend scrambling over the rocky banks, and musing on human and natural life here and . . . there. “There” in my present imagination -- the place where my mind goes when it isn’t here -- is the Amazon. A week ago, I returned from a cruise up that unimaginably mighty river, and its relentless waters seem to be flowing through me still.

Folded in the embrace of an Oregon spring, I’m dizzy with the softness of nature’s touch. The leaves of the snowberries are tender and tremulous, the wren songs that fill the woods are sweet, and the breeze that brushes my cheek is cool, then warm, like a questioning caress. Soon enough the heat of July will curl the leaves, subdue the stream, silence the birds – but today, nature speaks only of youth and hope, of life on the verge of being lived.

On the banks of the Amazon, there are no such moments of transcendental innocence. There, nature sings songs of experience. The Amazon is about what life can do, given world enough and time. For a naturalist, the spectacle is exhilarating, mystifying, awe-inspiring, and ultimately very, very humbling. As my companions and I nosed our small boat up narrow creeks and into the flooded forest, there was so much to see that I literally didn’t know where to look. There an iridescent blue Morpho butterfly flapped buoyantly just above the water. Here perched a trogon, a dignified bird soberly dressed in red and black, which suddenly opened its beak and barked like a dog. Up ahead, gigantic fruits hung down from a sprawling vine; but wait - was that the sound of monkeys crashing through the trees? Suddenly a pair of macaws flew over, their harsh shrieks ripping apart the still air – and what’s this?! -- a spider the size of my hand has dropped into the boat from an overhanging limb, and . . . You get the idea.

In the rain forest, nothing is as it seems, and the sheer abundance of life compounds its mystery. My normally irrepressible urge to classify and to understand was quickly defeated, but rather than causing frustration, this fostered wonder. Life in the tropics is so various, so fluid, so intertwined, that it is fundamentally beyond our power to specify. Like the Amazon itself, it changes faster than it can be described.