C. Drago’s “refutation” of strong vs. weak evidence
The alleged refutation
• Take a photograph of my class with me in it.
• Years later, view the photograph and note that I am no longer in it.
• Since we all know that I was there, the “strong evidence” photographs are unreliable.
• The “weak evidence” eyewitness reports are reliable.
• Conclusion: the “weak evidence” is stronger than the “strong evidence.”
The proper sequence for comparing strong and weak evidence
• Compare a photograph of a long-ago event with the memories of eyewitnesses.
• Experience inevitably shows that human memory is far less reliable than the photograph.
The flaw in the refutation
• Drago begins by building his answer into the premises (“Since we all know that I was there…”), i.e., the eyewitness accounts of the event are accurate.
• He then uses those premises to prove a restatement of the premises (“…the photographs are unreliable”).
• He then concludes that the premises are correct (“The photographs are weaker evidence than the eyewitness accounts”).
• He then generalizes about strong and weak evidence (“The ‘weak evidence’ is stronger than the ‘strong evidence’”).
• Building his conclusion into his premises and then proving the premises is a classic example or circular reasoning (begging the question, or assuming the truth of what he is seeking to prove).
His flawed extension to the autopsy photographs:
• The photographs show the exit wound in the right side/rear of the head.
• The eyewitnesses at Parkland saw the wound in the back of the head.
• This many trained witnesses cannot be wrong.
• Therefore the autopsy photographs are faked.
• The logical flaw here is assuming that many pieces of weak evidence can overcome fewer pieces of strong evidence.
• This error is equivalent to using his flawed refutation of the strength of photographic evidence.
His flawed extension to the back wound:
• There are many eyewitness reports of a low back wound, including a write-up by the president’s personal physician.
• These multiple eyewitness reports constitute far-stronger evidence than the objective measurements by Dr. Boswell of the high wound that he recorded on the face sheet.
• His reasoning: multiple weak evidence outweighs single pieces of strong evidence.
• The flaw: same as for the autopsy photographs.