Forensic Pathology News
“‘A flotation test and microscopic examination of the lungs was consistent with a live birth,’ the autopsy read. The baby, the medical examiners concluded, died of asphyxia and exposure from being left in the closet.”
[Note: You might think the problem has to do with an old-fashioned forensic test: “If the lungs floated, the theory behind the test holds, the baby likely was born alive. If they sank, the baby likely was stillborn.”
In truth, the problem is not the lung flotation test. The problem is the Sherlock Effect.
Sherlock Holmes would look at clues and use his intuition to describe the past events that led to those clues. Medical examiners saw lungs floating in water and imagined a temporarily living, breathing infant suffocating and being cold in a plastic bag in a closet. Both Sherlock and the ME’s look at clues and imagine past events from them.
That is not the same as figuring out if lung flotation is a good test. It is not nearly as good as the Inferential Test.
What should the ME’s have done instead?
Listen to what the woman said. She knew she was pregnant but decided to carry the baby to term without anyone knowing she was pregnant. She had contractions and, after having a strong urge to use the toilet, delivered the baby into the toilet.
She said at no time was the baby breathing. She pulled the baby from the toilet, wrapped him in a towel, carried him into the bedroom, and cut the umbilical cord with scissors. Then she “scanned the room and spotted a large Ziplock bag meant to store her daughter’s clothes. She placed her baby in the blue bag, and she put the bag in the closet.”
What were the clues? Blood soaking the carpet and smeared on the bathroom floor. Stains on the bathtub, closet door and hallway. A placenta still in the mother with a cut umbilical cord protruding from her. A well-developed term baby without injuries. Lungs that were pink in some areas but not in others. And, of course, the float test.
Then ask if the physical evidence could have resulted from what she said? If what she said could have happened the way she said it, we should accept it because she was there and we weren’t. We shouldn’t imagine events that were never witnessed.
And don’t bother to put the lungs in water to see if they float.]
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.”