6/13/2001 4:55PM
Dr. Rahn:
The Warren Commission’s "conclusion" that Lee Harvey Oswald, acting alone shot and killed President John F. Kennedy on November 22, 1963 at 1230PM CST, in Dallas, Texas has long been disputed.
You teach a course, purported to be on "critical thinking", which uses the assassination and the controversy surrounding the conclusions as its vehicle.
You once told me in an e-mail correspondence that you were "agnostic" as to your beliefs in whether or not the Warren Commission conclusions were accurate. The syllabus of the course includes a "ten-step" plan to analyze and evaluate the physical evidence of this case in a critical manner, not unlike a scientist would do when establishing a working hypothesis.
Based on your "further thoughts" it appears that, in contrast to your statement to me, you have indeed drawn the conclusion that Oswald acted alone. I assume that your hypothesis was/is based on a critical review of all pertinent physical evidence and scientific theory.
As a scientist, you are no doubt aware that any such hypothesis needs to withstand critical scientific and mathematic examination to determine its probability of being true and accurate.
In March, 2001, Dr. Donald B. Thomas reevaluated the acoustics data obtained by the House Select Committee on Assassinations. His work was peer-reviewed before being published in the British Forensic Science’s journal.
As you know, Dr. Thomas’ conclusions were that there was a statistically significant 96% probability that the fatal shot came from the area known as the "grassy knoll", thus being in conflict with the Warren Commission conclusions. As of the publishing of that article, there is now scientific evidence in the public domain that the Warren Commission conclusions were incorrect.
Based on Dr. Thomas' conclusions, on what scientific basis are you still maintaining the assumption, outlined in your "further thoughts" that..."There is an overwhelming absence of evidence that anyone else was involved?"
If you now concede that your assumption was/is incorrect, where does that place your hypothesis and the conclusions you've drawn?
E C Dorsch, Jr.
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Sent: Wednesday, June 13, 2001 10:14 PM
Subject: Re: Kennedy Assassination
Mr. Dorsch,
The borderline-snide tone of your message really turned me off. Nevertheless, I will answer it because it is so easy to deal with. The acoustic evidence cannot be taken seriously because it is so uncertain, so indirect and not backed up by anything truly physical. First, its origin is strongly in doubt. The purported motorcyclist wasn't even allowed to hear "his own" recording. It contains apparent crosstalk and sounds not from Dealey Plaza. Second, it is a series of clicks and pops that have to be deeply analyzed by computer to get anywhere. Shots cannot be heard by ear. There are too many blind steps between noise and alleged shots. Third, it results in an invisible shooter firing a disappearing weapon that left no bullets or fragments to be found. That is no way to prove a conspiracy.
One of the things I emphasize in my class is that a chain of logic can be no stronger than its weakest link. In this case, the weak link is the recording. It does no good to overanalyze something whose origin is unknown, especially when that something yields conclusions not supported by any other physical evidence.
Ken Rahn
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Thursday, June 14, 2001 12:55 AM
Dr. Rahn:
You explanation is amazing, though hardly unexpected. I merely asked what scientific basis you had to maintain your hypothesis. Your answer did not appear to address anything scientific. I am merely seeking to understand. My original query merely stated known or assumed facts. I have no idea why you would consider it "snide."
Addressing your response:
You do seem to believe it important having the motorcycle officer "hear his own recording", since you mention it.
For what purpose would his opinion be used?
That being asked, why should that testimony be more valid than that of any of the other witnesses, including those who observed anything having to do with shots from elsewhere, like the "knoll"? Footprints found physically place someone there. Witness testimony backs a shooter there. Films show photographic evidence consistent with smoke near that area immediately afterward, and the acoustics evidence supports a shooter there to a mathematically significant probability.
But, according to you, all this should be "critically" dismissed, because no one left a weapon or casings behind.
One would wonder how law enforcement could ever reconstruct a crime if the guilty party used a revolver or knife and took it with them.
On the other hand, based on the true and complete "physical" evidence, one cannot state without a "leap of faith" that any bullet coming from the recovered casings and fired from the weapon entered into evidence as the assassination rifle ever actually impacted with Kennedy, since no ballistically identifiable fragments were recovered during the autopsy, and the fragments/bullets that were ballistically traced to that weapon retained no physical evidence of passing through the body of John F. Kennedy.
How do you deal with that small flaw in the physical evidence, while maintaining the same scrutiny that is applied to "critical thinking?"
The validity of the acoustics evidence itself was not questioned by either the HSCA nor the NRC, yet you believe it to be strongly in doubt. Somehow, such an "opinion" on your part does not sound objective, scientific nor critical to me. It sounds subjective and convenient, especially given that you are not an acoustics expert.
While you are entitled to that opinion, I do not believe that you possess the necessary expertise to adequately validate nor invalidate the evidence itself. Therefore, you must be accepting a conclusion drawn by someone else with, we'll assume, the necessary expertise. However, that conclusion is disputed by another expert or panel of experts in the field who actually did a study of it.
Critically thinking, on what scientific basis is the conclusion you support the valid one?
The recording was analyzed by a scientific team of experts, and a study was undertaken, using known and validated theory and procedure (as part of the peer review of Dr. Thomas' article, the procedures/findings from the original study were again validated by an acoustics expert in the United Kingdom), yet again, in your "opinion" it is not valid because there is nothing "physical" to back it up...
Scientifically speaking, since the alleged assassination sequence and conclusions you support have never been duplicated, the hypothesis cannot be validated, nor other hypotheses ruled out.
Scientifically speaking, when a hypothesis cannot be validated, what are we to assume?
I tend to believe that your course undertakes the assassination from the wrong perspective. Rather than trying to disprove a conspiracy existed, it would seem more accurate to attempt to validate the original hypothesis first, using the same methods you apply to any conspiracy theory. When one understands that the Warren Commission hypothesis cannot be validated, one also understands that a conspiracy hypothesis is no less valid.
Ed Dorsch
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No response from Dr. Rahn
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Dr. Rahn:
6/22/2001
12:49PM
I forwarded your answers to my recent query about the acoustics evidence to Dr. Donald B.Thomas, the recent article's author. He has responded and granted me permission to forward those comments to you for further clarification and response. In an effort to eliminate the non-essential areas and concentrate on the differences, I have taken the liberty of editing both e-mails and doing a comparison of the points of non-agreement. If either of you feels the "edited" version is inaccurate, please let me know and I will post both e-mails verbatim:
Rahn/Thomas Exchange
June, 2001
RAHN: First, its origin is strongly in doubt. The purported motorcyclist wasn't even allowed to hear "his own" recording.
THOMAS: That McLain was not allowed to hear his own recording, if so, is irrelevant. McLain testified that he was probably on channel one and that he had trouble with a sticky microphone.. He identified himself in pictures as a motorcycle in the motorcade. Those are relevant points. What would be gained by having him listen or not allowing him to listen to the tape? He doesn't make any oral broadcast so what is the point? (see bottom for HSCA excerpts)
RAHN: It contains apparent crosstalk and sounds not from Dealey Plaza.
THOMAS: Yes it does (contain crosstalk), thankfully. That is how we know that the alleged gunshot sounds on the tape are exactly synchronous with the shooting. Why does that make the evidence invalid? I know of no such evidence (sounds not of Dealey Plaza). It is often alleged that the carillon bell on the recording is not in Dealey Plaza, but it has long been known that a carillon bell was audible in Dealey Plaza, at least it was in 1964 (it was captured on tapes made by news teams visiting the site on Nov 22, 1964) and Gary Mack spoke to a witness who claims that on the day of Kennedy's visit it was "playing hail to the chief." Apparently it was in a bank about 12 blocks away. I don't know what other sounds he means. It would help if Dr. Rahn's criticisms were more specific.
RAHN: Second, it is a series of clicks and pops that have to be deeply analyzed by computer to get anywhere. Shots cannot be heard by ear.
THOMAS: I am a little confused here. The clicks and pops are audible and they are the alleged gunshots. The sounds were analyzed by spectrograph and oscillograph. They were also digitized and fed into a computer. I don't understand specifically why he thinks the analysis done by BBN and WA was not adequate. The NRC panel didn't do anything that BBN had not already done. Again Dr. Rahn needs to be specific.
RAHN: There are too many blind steps between noise and alleged shots.
THOMAS: The proper way to determine if a recorded sound is, or is not, a gunshot is to record a gunshot under the same environmental conditions as the suspect sound was allegedly recorded, and then compare the physical characteristics of those sounds: e.g. the amplitude, frequency, waveform and the time-history of the impulsive components of those sounds. That is what BBN and WA did and no one knowledgeable of acoustic science, including the NRC panel, has ever criticized the methods used by the HSCA experts as Rahn is apparently doing. He should be more explicit in his criticism. What "blind steps" is he talking about? As a point of fact the same methods (echo location) have been applied in other cases of recorded gunfire to determine the position of the shooter, the most notable being the Kent State shooting and the Commie-Klan shoot out in Greenville, North Carolina.
RAHN: Third, it results in an invisible shooter firing a disappearing weapon that left no bullets or fragments to be found. That is no way to prove a conspiracy.
THOMAS: As far as the last comments about invisible shooter and disappearing weapon and no bullet fragments, I suggest that Professor Rahn needs to review the evidence a little more deeply. But these are non-acoustic issues so I will leave those aside.
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Excepts from the HSCA Report:
Following the hearing, the committee secured a copy of the daily assignment sheet for motorcycles from the Dallas Police Department and found that McClain had been assigned motorcycle number 352 and call sign 155 on November 22, 1963.(82) preliminary photographic enhancement of the films taken on Houston and Main Streets indicated that the number on the rear of the motorcycle previously identified as having been ridden by McLain was, in fact, 352. (83) He further stated that he was the officer in the photographs taken of the motorcade on Main and Houston Streets, and that at the time of the assassination he would have been in the approximate position of the open microphone near the corner of Houston and Elm, indicated by the acoustical analysis. (76) He did not recall using his radio during the motorcade nor what channel it was tuned to on that day. (77) He stated it usually was tuned to channel one. (78) The button on his transmitter receiver, he acknowledged, often got stuck in the "on" position when he was unaware of it, but he did not know if it was stuck during the motorcade. (79) The acoustical analysis pinpointing the location of the microphone, the confirmation of the location of the motorcycle by photographs, his own testimony as to his location, and his slowing his motorcycle as it rounded the corner of Houston and Elm (as had been previously indicated by the acoustical analysis),(92) and the likelihood that McLain did not leave the plaza immediately, but legged behind momentarily after the assassination, led the committee to conclude it was Officer McLain whose radio microphone switch was stuck open. (HSCA Report pgs 76-79) ***************************************************************
I feel that this point and exchange is worthy of mention on my website listed below, which has had in excess of 94000 hits since I began it in 1999. I am not sure at this point if we have a difference of opinion based on interpretation or a contradiction of fact. In either case, it is important that it be rectified rather than "left hanging" as too many points of contention in this event have been. Since both of you gentlemen are scientists, it would appear that specific, documented criticisms and rebuttal, rather than generalizations are in order.
I look forward to Dr. Rahn's response.
Ed Dorsch
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6/22/2001
2:03PM
Mr. Dorsch,
I am surprised and disappointed that you forwarded my comments on acoustics to Dr. Thomas, or to anyone else, for that matter, for further comment without my permission and without any indication that you intended to do so. My remarks were meant for you and you alone. We all know that we write differently depending on circumstances and recipients. I was writing to you in an aggrieved, abbreviated manner because of the tone of your previous communication to me. For you to then unilaterally forward those remarks to Dr. Thomas was a breach of etiquette. My sincere apologies to him. Why you then chose to ask permission of him without having previously asked the same of me is a mystery.
I have no idea whether I will carry on this correspondence. You certainly have put a bad taste in my mouth over the whole thing. Anyhow, I never intended to be drawn into a long back-and-forth over acoustics, which is not one of my strong areas within the JFK assassination.
Kenneth A. Rahn
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6/22/2001
3:23PM
Dr Rahn:
If your response was private, you should have so stated, up front, not after you were called on it.
I understand that there is a certain "professional courtesy" between those in the field of science. However, when you choose to disagree with someone else's published work, regardless of your forum of presentation, you are liable for your actions.
You have the opportunity here to restate your position on a more scientific basis...which is exactly the question I asked in my original query. You certainly chose to answer that; now you are stating that you do not have the knowledge to have done so...I am confused sir. Why wasn't that the answer you gave me?
To a poor layman like myself, it appears that such actions set a double-standard, dependent upon the background of the solicitor. One might consider that very prejudicial.
Am I to be treated, and given answers differently because I do not have what you would consider a "worthy" background?
Dr. Thomas did not treat me so.He explained the basis for his article and conclusions in great detail and he answered all my questions...even the "unworthy" ones...completely. And I asked his permission because we have a pre-dated agreement, stemming from our initial communications about his article. I have no such agreement with you, nor did you ask for one.
With all due respect sir, it also appears very convenient that you might seek to avoid having your argument rebutted by someone of equal stature because you weren't told he might be asked to comment. You certainly did not "fear" to address me...
It is of course your prerogative to not respond. However, I, in the essence of truth, will have to consider posting your refusal...and your reasons...on my website, so that those interested in this may decide for themselves...as you told me you promoted in your course.
I seem to remember denying you permission some time ago to utilize my website for that course, yet you still saw fit to post both my personal, biographical data, and a link to my site from yours...perhaps we both could use some training in etiquette.
Ed Dorsch