Bytrial and error - trying things, making mistakes, andlearning from those mistakes - wehave figured out how to makeelectric light, to paint the ceiling of the SistineChapel, to fly.
Instead, to judge by the most comprehensive study on the reliability of forensic evidence to date, the error rate is more than 10% in five categories of analysis, including fiber, paint and body fluids. (Meaning: When the expert says specimen X matches source Y, there's a 10% probability he's wrong.) DNA and fingerprints are more reliable but still not foolproof.