Can an 'Expert' testify about what 'probably is true'?

Drewbot

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Drewbot
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What follows is a quote from Bill Munns, the recently anointed costume expert of Bigfootry, who believes the famous Patterson Bigfoot film is of a creature, and not a person in a suit. The in thread post can be found here: http://www.forums.randi.org/showpost.php?p=6905801&postcount=5401


In this quote he is citing the expertise of a person from Dwayne's Photo, 'the last film lab in the USA to actually process Kodachrome'. The person is supposed to be answering the question of the drying time for K-12 process film, however, the expert says "I don't know" for Kodachrome II, and instead cites that K-14 took about 50 minutes.

My question is this; Can an experts testimony be cited as a reasonable argument, if the expert is speculating about something he claims he does not know?

(My bolding)
Bill Munns said:
Processing Kodachrome film, (from Dwayne's Photo, the last film lab in the USA to actually process Kodachrome:

Dwayne's Photo said:
"Here is some information from our V.P. of Operations:
I don’t know for Kodachrome II - that was the K-12 process. But for the more modern K-14 process the “Dry to Dry Time” – from when the film goes onto the processor to when it takes up after the dryer is about 50 minutes. I doubt it was a lot different for K-12 and it certainly would not have been more than 15 minutes different either way. He also needs to understand that how long the entire film takes to process depends on how many total feet of film there are to process. The answer above is for a given piece (you could think of it as a given foot) of film. That time is fixed by the type of film process (in this case Kodachrome) and does not change based on the speed of the individual film processing equipment. If there are thousands of feet of film to run then how long it takes the entire film to be processed is governed by how fast the processor runs. For example, if the processor runs at 50 feet per minute and you have 5,000 feet of film to develop it will take 100 minutes to feed the entire 5,000 feet of film into the processor and 150 minutes for it all to take up at the dryer.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" />
If this is confusing – I’ll be happy to talk to the customer and explain it.
-(Name Removed by Drewbot)"
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As usual, the members of this forum are just spouting false facts, like a claim it takes 36 hours to process Kodachrome film.*

Bill
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I find it particularly ironic that he put this statement in at the end.
 
Drewbot said:
What follows is a quote from Bill Munns, the recently anointed costume expert of Bigfootry, who believes the famous Patterson Bigfoot film is of a creature, and not a person in a suit. The in thread post can be found here: http://www.forums.randi.org/showpost.php?p=6905801&postcount=5401


In this quote he is citing the expertise of a person from Dwayne's Photo, 'the last film lab in the USA to actually process Kodachrome'. The person is supposed to be answering the question of the drying time for K-12 process film, however, the expert says "I don't know" for Kodachrome II, and instead cites that K-14 took about 50 minutes.

My question is this; Can an experts testimony be cited as a reasonable argument, if the expert is speculating about something he claims he does not know?

(My bolding)


I find it particularly ironic that he put this statement in at the end.
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For my money someone who is an expert and states " i don't know" should have avoided mentioning the subject all together.

It is a huge red flag to me, because of its ability to modify data. And i see it used all the time , especially in regards to people claiming woo.

Usually it goes much like in your op " I don't know about X but i do know about something that i can assure you works just like X." Well, wait a ******* minute, if you don't know about X how do you know that the thing that works just like X actually works just like X?

I don't know if this type of fallacy has been specifically named yet, but if not i leave the honor to you.
 
You can usually say "I don't know" but still make an educated guess. In the specific case if you know the development time of similar films for example, and you know that no other film in the industry *ever* took that much time, you can guesstimate the time.

So the question now can be returned to those stating the claim that the film took 36h of dev (and make no mistake : it is a positive claim made by skeptic, therefore the burden of proof is on them) . If you have reference of such film taking similar time, then you can show those reference and the expert don#t really count since his primary response is "i don#t know".

OTOH if you don't have reference, and no similar film showing such dev time of 36h, I would go with the expert by default as first approximation, *OR* go neither way (dev time cannot then be taken into account in any argument whatsoever).

But the bottom line is that I will tend to agree partially with Munns, that if you claim the 36h , the burden of proof is on you, especially since expert guessestimate oder of magnitudes lower than the 36h.
 
To my knowledge (as an ex-photographic technician). The only time it would ever take 36 hours to develop and process a film would be if you measured it from the moment you dropped it off at the lab until when you were told to come pick it up again.

Yes genuinely, when we used to state "24 hour processing" some peple used to think it actually took that long to go through the machine! :confused:
 
Aepervius said:
You can usually say "I don't know" but still make an educated guess. In the specific case if you know the development time of similar films for example, and you know that no other film in the industry *ever* took that much time, you can guesstimate the time.

So the question now can be returned to those stating the claim that the film took 36h of dev (and make no mistake : it is a positive claim made by skeptic, therefore the burden of proof is on them) . If you have reference of such film taking similar time, then you can show those reference and the expert don#t really count since his primary response is "i don#t know".

OTOH if you don't have reference, and no similar film showing such dev time of 36h, I would go with the expert by default as first approximation, *OR* go neither way (dev time cannot then be taken into account in any argument whatsoever).

But the bottom line is that I will tend to agree partially with Munns, that if you claim the 36h , the burden of proof is on you, especially since expert guessestimate oder of magnitudes lower than the 36h.
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The thing is though, the " i don't know about X" comment, can , and usually is simply obfuscation.

I could say " I don't know about a katana, but the average length for a kukri is about 9 inches." now assuming your talking to someone that does not have much knowledge of weaponry, your point is that the katana is approximately 9 inches. And as long as they don't have that information, it is going to be fairly easy to convince them.

It would be much more honest to say " Well i don't know, i guess we should do the research on it and find out. " It not only encourages research, but eliminates the ability to use your " non knowledge" as an easy way to prove a point.
 
Drewbot said:
My question is this; Can an experts testimony be cited as a reasonable argument, if the expert is speculating about something he claims he does not know?
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Quick answer : yes, but you have to weigh it against how little he actually knows.

The Federal Rules of Evidence (if you're talking "testimony," you're talking "rules of evidence") state that:

FRE_702 said:
If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise, if (1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.
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So, he's expressed an opinion, based on the facts/data as he knows them from his experience (one of those facts being that K-12 is not that different from K-14, no more than 15 minutes different either way).
 
sadhatter said:
The thing is though, the " i don't know about X" comment, can , and usually is simply obfuscation.

I could say " I don't know about a katana, but the average length for a kukri is about 9 inches." now assuming your talking to someone that does not have much knowledge of weaponry, your point is that the katana is approximately 9 inches. And as long as they don't have that information, it is going to be fairly easy to convince them.

It would be much more honest to say " Well i don't know, i guess we should do the research on it and find out. " It not only encourages research, but eliminates the ability to use your " non knowledge" as an easy way to prove a point.
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It depends on what's under debate. If someone is trying to sell you a 6 inch katana, it would be perfectly valid to say, "I don't know a lot about a katana, but the average length of a kukri is about 9 inches and I believe a katana is longer, so this doesn't sound right."
 
I don't even know wher the 36 hr claim came from. I do know that in Long's Making of Bigfoot, an exec at Kodak labs said it took at least two hours just to get the chemicals up to the proper temperature. I would think the 36 hour claim might include driving from Yakima to Seattle and back to Yakima for processing. But like I said, I am not sure where the 36 hour claim has been made.
 
Hitch said:
It depends on what's under debate. If someone is trying to sell you a 6 inch katana, it would be perfectly valid to say, "I don't know a lot about a katana, but the average length of a kukri is about 9 inches and I believe a katana is longer, so this doesn't sound right."
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That is kind of the opposite of the situation i am speaking of though. In that case, it is simply holding off judgment until one has the information and using information one does have to make an decision. There is no convincing trying to take place.

It is all in how it is used, really. Once it is used to assert a positive versus when it is used to question a premise, is when the problem arises.
 
Drewbot said:
My question is this; Can an experts testimony be cited as a reasonable argument, if the expert is speculating about something he claims he does not know?
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As far as the law goes, no one can testify about anything they do not know.

An expert may give an opinion but only if that opinion would be helpful to the court and there's some reason to believe the person actually has expertise in the area.

In this case, this expert claims two things: 1) he doesn't know; and 2) he knows a lot about film that causes him to believe something about the subject. In case 1, the expert clearly cannot give an opinion. In case 2, he may possibly be able to. However, the person has to establish some expertise in how he is able to guess. Additional facts that would make his testimony admissable might be: that he has decades of experience in film and newer processes are always faster than older ones; that kodak launched its newer film process with a big campaign about it being faster than the old process; that all wet film processes have always taken this amount of time (because the limiting factor is thechemistry of the reagents or something other than the composition of the film); etc.

But, on the testimony given, I would rule the opinion inadmissible and send the attorney back to lay a better foundation with the witness.
 
Drewbot said:
My question is this; Can an experts testimony be cited as a reasonable argument, if the expert is speculating about something he claims he does not know?
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I think this question isn't precise enough to answer.

What I mean is, there's different types of not knowing something. Take, for example, a civil engineer. If you ask him what load a steel I-beam can bear the answer will be "I don't know, but a standard I-beam will bend X inches over Y feet under Z static and Q impact load". He knows the applicable theory, but does not have enough information to apply that theory to this problem. In contrast, if you ask him "What is the depositional environment of the Silica Formation?" he'll look at you like you're from another planet. He doesn't know the applicable theory, so even if he knows the specifics he can't answer the question.

In the case of not knowing the specifics but knowing the thoery, the expert testimony can be used (outside of court; I have no knowledge of the court system) to constrain reasonable limits to things. They can set an upper and lower bound. That's not to say that if it exceeds what they say one way or the other we reject it, or if it doesn't we accept it, without thought--the expert's statements merely provide a quick and dirty way to assess a statement. A statement that this Brand New I-beam can hold up to one ton static load! will generally be greated with little skepticism; it's the equivalent of saying "I drank coffee this morning"; no one will be surprised (except that the number is, to my understanding, very low). If they say that the Brand New I-beam can hold a gigaton impact weight we can demand more evidence before we accept the statement.

In the case you presented in the OP, I'd take the expert's opinion as setting the limits of what's expected, and therefore what can be accepted without requiring aditional research. Specifically, any claim of a dry time between 35 and 65 minutes would fall under the category "That seems reasonable". Anything beyond would fall under the category "I'm going to need something to back that statement up".

In short, experts discussing things where they know the theory, but do not know the specific applications, are essentially establishing what is an ordinary claim requiring ordinary evidence vs. what is an extraordinary claim requiring extraordinary evidence.
 
What if I went to a computer expert and asked him how long it would take a Commodore 64 to figure out Pi to x trillion places, and he said "I didnt start working on computers until the Pentium came out, but I would assume it would be less than a second."?
 
Obviously he would be a bad expert. He wouldn't know the theory (in this case, processor speed).
 
that is my point, if you are an expert on processing of film, would you say " I don't Know about film X, but film Y is like this, therefore my claim about X must be true."?
 
Drewbot said:
What if I went to a computer expert and asked him how long it would take a Commodore 64 to figure out Pi to x trillion places, and he said "I didnt start working on computers until the Pentium came out, but I would assume it would be less than a second."?
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At least in court, the question would be why the "expert" assumes that. If the person can show a knowledge of the subject area so authoritative that his opinion can be trusted, it would be admissable. So, he might say, "I've never worked on a Commodore 64, but calculating Pi is a fundtion of processor speed and the C64 could do this many calculations per second, thus x trillion calculations would take it at least this long," it would be OK.

Since "less than a second" is clearly nonsense, your "expert" would have a hard time demonstrating the expertise necessary to give such an opinion.


ETA: My research indicates the C64 could perform fewer than 1 million calculations per second. A trillion calculations would have taken a million seconds, or eleven and a half days. I imagine the actual time would have far exceeded that.
 
that is my point, if you are an expert on processing of film, would you say " I don't Know about film X, but film Y is like this, therefore my claim about X must be true."?
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It's not a fair comparison. First, it's nearly impossible that a computer expert would fail to understand processor speed through time--even if he's vaguely aware of things like processor speed he'd assume that a C64 would take orders of magnitude longer to do a problem than a modern processor. In contrast, chemical photo development hasn't changed significantly in the lifetime of anyone posting here (or their parents).

Secondly, as I said, the computer guy you created doesn't understand the theory behind computer processing. This isn't a question of minor adjustments to similar technology; it's the difference between a horse and buggy vs. an F-22. If you're going to ask an "expert" who doesn't know the topic you're going to get bad answers. This is not comperable to someone how knows the general theory and is merely speculating on a particular application.
 
I've been qualified in a state court as an expert witness in like 5 areas. It was pretty darn easy considering I know how much I DON'T know about those subjects. I guess that actually is the hallmark of an expert - you know all the mistakes you can make because you've made them.

A good lawyer would ask "In your expert opinion, do you think such-and-such..?" But, the judge doesn't have to believe you're credible. In fact, it often comes down to credibility of the witness as a whole. If I say "I don't know", I'm being honest. It's better than speculating where you have no data to go on.
 
There is general knowledge about an area that can apply to specific cases, even when you have no direct experience with those cases.

A car expert who's never driven or worked on a particular model year can still probably give you a reasonable ballpark for the miles per gallon it gets, within a window. I know absolutely nothing about cars and I can tell you that a 1987 Ford truck probably got less than 60mpg and probably more than 4mpg.

It is very easy for someone with a basic knowledge of a process and the history of it to make an accurate educated guess.

The expert quoted above said:
it certainly would not have been more than 15 minutes different either way
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If I told you I'd never driven a 1989 Ford, but I knew the MPG for the 91 and told you it certainly wouldn't be more than 30mpg either way, isn't that reasonable?
 
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