PSC482G, Spring 2000
Answers to Assignment 4
Critical thinking 4
Read: “Science, pseudo-science, and falsifiability,” by Karl Popper, and “A modified scientific method for the JFK assassination.”
Answer these
questions:
Let us have a practice run on using the pattern of critical thinking described
at the end of the essay on the modified scientific method. For basic data, we
will use the 25 pieces of evidence from Assignment 3. I give you the question
and the evidence, and you do everything else. By “everything else,” I mean
taking the evidence through as many of the steps of the modified scientific
method as you can, recognizing that you are still in the very early stage of
studying the assassination and how to think about its evidence. Good luck!
1. The question: Who killed John F. Kennedy?
2. List all preconceived answers, now matter how bizarre or biased.
a. Lee Harvey Oswald acting alone.
b. Lee Harvey Oswald as part of a conspiracy.
c. Unknown person acting alone.
d. Unknown conspirators without Oswald.
3. List all relevant evidence. (Use this partial list. Feel free to supplement it with other evidence you may know.)
1. Three spent cartridges were found in the sniper’s nest on the sixth floor of the Depository.
2. One entrance wound was found in the rear of JFK’s head; one in his back.
3. The Zapruder film shows that Kennedy’s head moved forward, then back.
4. Immediately after the shooting, police and the crowd rushed up the grass toward the picket fence.
5. Many witnesses recalled hearing shots from the direction of the grassy knoll.
6. Many witnesses heard shots from the direction of the Depository.
7. Howard Brennan saw a sniper fire the last shot from the Depository.
8. Metal fragments in JFK’s head formed a cone opening from the small rear wound to the large missing area of skull on the right side.
9. The area of the limousine in front of the Kennedys was covered with blood and tissue.
10. Most witnesses heard between two and five shots.
11. At least two persons in Dealey Plaza smelled gunpowder at ground level.
12. Extreme enlargement of Mary Moorman’s Polaroid photo shows two or three figures behind the picket fence on the knoll.
13. As William Morrow wrote in his two books, he bought three identical Mannlicher-Carcano rifles for use in the assassination.
14. Of the three large bullet fragments recovered, two were traceable ballistically to Oswald’s rifle to the exclusion of all other rifles.
15. The bullet recovered from the stretcher in Parkland Hospital is both traceable to Oswald’s rifle and pristine.
16. Between the hits to Kennedy and Connally’s bodies, there was insufficient time for a shooter using Oswald’s rifle to refire.
17. The diffuse cloud of fragments from JFK’s head moved forward, upward, and to the sides.
18. A motorcycle policeman to the left rear of the limousine was hit on his right side by fast-moving fragments from JFK’s head.
19. One witness saw a man carry a rifle up the grassy knoll shortly before the assassination.
20. As Oswald said, he was eating lunch in the second-floor lunchroom at the time of the shooting.
21. A photo of the Depository, when greatly enlarged, shows a human figure in another sixth-floor window.
22. A number of witnesses saw a man behind the picket fence break down a rifle immediately after the shooting, put it into a case, hand the case to another person, and stride rapidly away from the scene.
23. Footprints were found in a muddy area behind the grassy knoll.
24. Beverly Oliver, the “babushka lady” who was just to the left of the president’s limousine at the time of the head shot, looked right down the barrel of a rifle being fired from the top of the knoll.
25. Nearly all the medical personnel at Parkland Hospital saw the fatal wound in Kennedy’s head at the rear, not on the right side as the autopsy photos show.
3a. Divide the evidence into strong and weak, where “strong” means critically testable” (falsifiable). To the extent that you know which of the strong evidence has been validated, use only it.
Strong
1. Three spent cartridges were found in the sniper’s nest on the sixth floor of the Depository.
2. One entrance wound was found in the rear of JFK’s head; one in his back.
3. The Zapruder film shows that Kennedy’s head moved forward, then back.
4. Immediately after the shooting, police and the crowd rushed up the grass toward the picket fence.
8. Metal fragments in JFK’s head formed a cone opening from the small rear wound to the large missing area of skull on the right side.
9. The area of the limousine in front of the Kennedys was covered with blood and tissue.
12. Extreme enlargement of Mary Moorman’s Polaroid photo shows two or three figures behind the picket fence on the knoll.
14. Of the three large bullet fragments recovered, two were traceable ballistically to Oswald’s rifle to the exclusion of all other rifles.
15. The bullet recovered from the stretcher in Parkland Hospital is both traceable to Oswald’s rifle and pristine.
17. The diffuse cloud of fragments from JFK’s head moved forward, upward, and to the sides.
18. A motorcycle policeman to the left rear of the limousine was hit on his right side by fast-moving fragments from JFK’s head.
21. A photo of the Depository, when greatly enlarged, shows a human figure in another sixth-floor window.
23. Footprints were found in a muddy area behind the grassy knoll.
Weak
5. Many witnesses recalled hearing shots from the direction of the grassy knoll.
6. Many witnesses heard shots from the direction of the Depository.
7. Howard Brennan saw a sniper fire the last shot from the Depository.
10. Most witnesses heard between two and five shots.
11. At least two persons in Dealey Plaza smelled gunpowder at ground level.
13. As William Morrow wrote in his two books, he bought three identical Mannlicher-Carcano rifles for use in the assassination.
16. Between the hits to Kennedy and Connally’s bodies, there was insufficient time for a shooter using Oswald’s rifle to refire.
19. One witness saw a man carry a rifle up the grassy knoll shortly before the assassination.
20. As Oswald said, he was eating lunch in the second-floor lunchroom at the time of the shooting.
22. A number of witnesses saw a man behind the picket fence break down a rifle immediately after the shooting, put it into a case, hand the case to another person, and stride rapidly away from the scene.
24. Beverly Oliver, the “babushka lady” who was just to the left of the president’s limousine at the time of the head shot, looked right down the barrel of a rifle being fired from the top of the knoll.
25. Nearly all the medical personnel at Parkland Hospital saw the fatal wound in Kennedy’s head at the rear, not on the right side as the autopsy photos show.
3b. Proceed with the tested and validated evidence only.
The validation process removes items 12 and 21, the alleged figures in the Moorman photo and in a second sixth-floor window. That leaves the following pieces of strong evidence:
1. Three spent cartridges were found in the sniper’s nest on the sixth floor of the Depository.
2. One entrance wound was found in the rear of JFK’s head; one in his back.
3. The Zapruder film shows that Kennedy’s head moved forward, then back.
4. Immediately after the shooting, police and the crowd rushed up the grass toward the picket fence.
8. Metal fragments in JFK’s head formed a cone opening from the small rear wound to the large missing area of skull on the right side.
9. The area of the limousine in front of the Kennedys was covered with blood and tissue.
14. Of the three large bullet fragments recovered, two were traceable ballistically to Oswald’s rifle to the exclusion of all other rifles.
15. The bullet recovered from the stretcher in Parkland Hospital is both traceable to Oswald’s rifle and pristine.
17. The diffuse cloud of fragments from JFK’s head moved forward, upward, and to the sides.
18. A motorcycle policeman to the left rear of the limousine was hit on his right side by fast-moving fragments from JFK’s head.
23. Footprints were found in a muddy area behind the grassy knoll.
4. List all possible answers, however unlikely, consistent with the facts in 3b.
a. Oswald did it alone.
b. Oswald did it with help.
c. Some unknown person did it alone.
d. Unknown persons (less Oswald) did it.
(All four original explanations remain possible.)
5. Choose the simplest answer consistent with all the facts.
a. Oswald did it alone.
N.B. Answer (c), “Some unknown person did it alone,” is less simple than (a) because it involves putting someone on the sixth floor for whom there is no evidence and allowing him to fire a rifles that was not his.
6. Test your answer rigorously against its consequences (predictions) or against new evidence gathered explicitly for the purpose. (We will be doing this for the rest of the semester.)
a. Consider the answer proven if it passes the test and no other answer is possible.
Answer (a) cannot be considered proven because the other three answers remain possible.
b. Retain the answer if it passes the test but other answers are possible.
Answer (a) is retained provisionally as the required starting point.
c. Reject the answer if it fails the test. (To come?)
7. If the answer was rejected, continue testing progressively more-complex answers until one is found that survives.
N/A (yet).
8. Retain this answer as a working hypothesis until new evidence forces you to reject it.
Working hypothesis is (a) Oswald did it alone.
Note to the class: We have the rest of the semester to disprove this working hypothesis! There is much more evidence that can be brought to bear.