38. Objections and responses

Does not incorporate the blur analysis of the Z-film
Perhaps the major objection to this work could be that it takes Josiah Thompson's measurements of Kennedy's motions at face value and does not deal with the recent claims that the blurred image in frame 313 hides the fact that the head did not snap forward quickly at that time. Thompson has recently supported this view, claiming that he is now convinced that his original measurements were wrong. He based his conclusions on "A Motion Blur Analysis of the Zapruder Film" by David Wimp, which appears at the time of this writing on Ron Hepler's web site (http://server3002.freeyellow.com/rhepler).
There are several reasons why this view is incorrect. It is also largely irrelevant to the calculations presented here. The first reason why it is wrong is the simplest—you can see clearly that the head did indeed snap forward. You can even see the angle of the back of Kennedy's head shift to the right. To the extent that frame 313 is blurred, it will mean that the head snapped even farther forward than the frame appears to show (and as confirmed by the calculations). The second reason is that the head had to snap forward—neutron activation analysis (NAA) of the fragments in the brain matches them to the large fragment in the front seat, and ballistics traces this fragment to Oswald's rifle. As shown in great detail in earlier sections here, the forward speed of the snap and the distance traveled can be easily estimated from the mass of the bullet and its entrance and exit velocities, and they are completely consistent with the measurements. If anything, they exceed the measurements. It all fits into a coherent picture that cannot be denied.
Most importantly, however, the motions around frame 313 do not have to be known precisely because the calculations of the lurch essentially skip over them—they predict the velocity of the lurch after the snap is finished and do not use the values of the snap in that calculation. A clear speed of -0.8 ft s-1 can be seen in 314–315, quite independent of anything that happened in 312–314. So the conclusions of this work remain valid no matter what one thinks of the snap's existence or nonexistence.

Expanded discussion of the noneffect of blurring

Assumes that the Z-film is genuine
Obviously, this work assumes that the Zapruder film is genuine. It is ludicrous to think that it is anything else. Thompson has effectively destroyed the myth of alteration in a brilliant essay that is posted here.

Accepts the NAA uncritically
This monograph accepts the neutron activation data on the lead fragments only after the exhaustive analysis that appears elsewhere on this web site.

Accepts the other physical evidence uncritically
The basic physical evidence in this case is not accepted uncritically. On the contrary, it has been examined carefully and repeatedly and found to be self-consistent and multiply redundant. The simple, direct picture provided by this evidence has been challenged many times, but never successfully, nor has an alternate picture ever been successfully provided.

Does not provide a standard for accepting or rejecting physical evidence
It is true that this monograph does not provide a codified procedure for validating physical evidence. Instead, it validates by example. I hope to formalize these procedures in the near future.