Can't lawyers and mathematicians just get along? Last week the Guardian reported that an appeals judge in London threw out a murder conviction because he objected to an expert witness's use of a statistical tool. In the original trial, a footwear expert had been summoned to determine whether a shoeprint found at the crime scene could have been produced by a pair of sneakers found at the defendant's home. The expert's stilted conclusion: It was "somewhat unlikely that the observed correspondence would have been obtained as a result of mere coincidence."

He'd...