When it's at its most self-aware, "Rivers and Tides" precociously tweaks the pessimist's view of art as an exercise in futility. Moving at a slow, sometimes glacial pace, the documentary traces the creative process of Andy Goldsworthy, a British artist who makes elaborate sculptures and tableaux from natural objects. In his trained hand, ice crystals are arranged into extended, snakelike formations, and simple stones become egg-shaped structures of imposing height. Almost all of this work is performed on site, so Goldsworthy's quirky forays are defined by a sense of impermanence: Even the sturdiest of his constructions will fall victim to erosion, while others will more rapidly decompose due to exposure to direct sunlight or -- in the case of the many pieces that he erects by the seaside -- the unstoppable forward motion of the waters. In many cases, the photographs he snaps of his creations soon become the only evidence that they existed at all.
Goldsworthy is reasonable enough to know how eccentric all of this looks: In one of the movie's lighter passages, he jokingly chides filmmaker Thomas Riedelsheimer to "do something useful" by abandoning his camera and helping to gather stones for a sculpture in progress. But the artist (who creates his pieces on commission) is after more than a simple race against the clock. He says his endeavors constitute an ongoing quest to understand nature -- to respect its changes and find a responsible role for mankind within them. And the fate that awaits his works is not destruction, he argues, but the transition to another plane of being.
That kind of talk can get a bit discomfiting, especially when it's accompanied by footage of a diligent Briton assembling rocks like a kid wrestling with Lego blocks. One attempted tower collapses in a heap a full four times (two of which are captured on camera), bringing the normally stoic Goldsworthy to the brink of his patience. Yet at such moments, "Rivers and Tides" momentarily puts its finger on the quantity that separates a great doc from a glorified short: the ability to use a discovered curiosity as a metaphor for something bigger.
In this case, that something bigger exists beyond the confines of the subject's own personality. Though there's some talk of the personal concerns that compel Goldsworthy -- the death of his younger brother's wife, he says, intensified a pre-existing interest in human transience -- the film fails to pinpoint where the intellectual fire came from in the first place, or why he chose this particular outlet for it. (While the prevalence of hole-shaped images in his work would give a Freudian psychologist material for a year, he says that they merely signify "entrances" into new stages of life. Oh, right.)
It's the importance you the viewer invest in Goldsworthy's work that gives the movie any significance. In the collapse and reconfiguration of those stone still lifes, one can detect the echoes of centuries' worth of philosophical hand-wringing over the pitfalls of ambition. To take the most recent example, there's the almost Biblical self-critique America experienced over the wrecking of the Twin Towers: In our forward-charging hubris, did we build them too big to begin with? And dare we pile anything that high again?
To Goldsworthy, of course, the risk of comeuppance lies not in other men but in the routine motions of the Earth itself. Early in the film, he remarks that the forces that give his creations life are also those that must bring about their deaths. Oh, Mother Nature; you always hurt the one you love.