IN ROBOTICS there is something called the "uncanny valley." The idea is that as a robot starts to resemble a human, humans like it more and more. This continues up to a point, at which we become repulsed by a device that looks and acts almost like us, because we recognize something as lifelike, but not alive.

Fiction is a similar exercise. The novels of Peter Carey (True History of the Kelly Gang, Oscar and Lucinda, and many others) seem purposefully to toe that line: Characters are realistic and credible, but often mimic even the act of reading their own lives as stories.

In his newest, The Chemistry of Tears, two stories commingle. In one, Catherine Gehrig, a museum horologist—she specializes in clocks—whose lover has just died, is given a mysterious automaton to restore, accompanied by a box of journals.

The journals are by Henry Brandling, an English semi-nobleman. He's a bumbler, but so hopelessly dedicated to his dying son as to commission a toy for him—a clockwork duck (with working digestion)—from a probably mad clockmaker in a small village in the Black Forest in 1854.

To complicate matters, Henry begins to transcribe the autobiography of "his German," the mad clockmaker Sumper. This leads to the miasma of Catherine reading Henry's summation of Sumper's life. Carey brilliantly intertwines the three voices: Catherine, drunk on vodka and grief; Henry, desperate not to lose his son; Sumper, insistent on the existence of higher forms of life (yes, aliens).

In one scene, a Victorian "genius" explains that his computing machine has not been mistaken in finding the sum of 2 and 102 to equal 171. Rather, he has installed a mechanism to force an error in its calculation. "In nature," he says, "we would call this a miracle and I, who predicted it, would be called a prophet."

The natures of fallibility and falsity are central to The Chemistry of Tears. Henry and Catherine suffer the same unwillingness to see what is in front of them. Each often assumes some truth, only to immediately be proven wrong. And as Henry doubts Sumper, Catherine doubts Henry, and the reader is left to doubt all three.

The emotional impact of the novel connects because of the intellectual disconnect between the stories. It leaves the novel feeling like the clockwork duck—or, by story's end, swan: "creepily sinuous and sensuous." It's lifelike, not alive, but not less than alive, either.