Forensic Pathology News
“In his new book, Wrongfully Convicted: Guilty Pleas, Imagined Crimes, and What Canada Must Do to Safeguard Justice, Roach dissects the blinkered legal system that has upheld and induced these miscarriages of justice in Canada for decades. One case changed the course of his career: Donald Marshall Jr., who spent over 11 years in prison for a murder he did not commit. ‘Marshall was a crash course in wrongful convictions and how they happen,’ Roach says. ‘I teach it every year, and I get mad about it again every year.’”
[Note: Author Kent Roach may get mad every year, but I doubt his book mentions the Inferential Test. It should. Everybody should understand the basic logic behind the IT, but people either ignore it or fail to understand it. In case you forgot it, the IT is: One can be reasonably certain if witness accounts of the past are consistent or not consistent with physical evidence in the present, but one cannot reliably surmise past events from physical evidence unless there is only one plausible explanation for that evidence.
Look at the Marshall case, for example. Seale and Marshall encountered Ebsary and MacNeil. With a knife, Ebsary slashed Marshall in the arm and fatally stabbed Seale in the stomach, but the police and the court charged Marshall with the crime instead of Ebsary.
Marshall provided a witness account consistent with the physical evidence, including being slashed in the arm, but the police and the court ignored that account, preferring other testimony that was not consistent with the slash in Marshall’s arm. Why did they believe the inconsistent testimony? Because the physical evidence of Marshall’s race allowed the police and the court to surmise the past events of Marshall murdering Seale.
The IT lays bare the stupidity, but year after year, not only Canadians but also others throughout the world repeat unrecognized stupidity. Authors may write books and talk about crash courses, but we could learn more from the IT than from any book or crash course.]
Whenever an expert states the past events that occurred on the basis of looking only at the physical evidence without reference to eyewitness statements, he or she is Affirming the Consequent for Complex Past Events. This is not only logically invalid and unsound, it never works in practice, Sherlock Holmes, CSI and Bones notwithstanding. Whenever ACCPE is listed in my comments to a news article, recognize one more tragic example of how this fallacy can destroy lives. ACCPE can also be understood as “backward reasoning, “effect-to-cause reasoning,” or “abductive inference.”