Evidence is accidental: Items are transformed into evidence by their involvement in a crime regardless of their source or mode of production. By becoming evidence, their normal meaning is enhanced and expanded. Evidence is initially categorized much as the real world. Forensic science adds to this classification to further enhance or clarify the meaning of evidence relevant to the goals and procedures of the discipline. Most evidence, including DNA, has value at the class level, although it can be exceedingly specific in its classification. While uniqueness may be assumed, individualization in an inherently nonprovable claim; statistical interpretations of evidence may be required.