Page 2 of 2
Re: "Infinite Variation"
Posted: Wed Jan 06, 2010 10:06 am
by Gerald Clough
Dr. Dror wrote:Not sure how this interesting theoretical discussion on 'infinite' is going to help.... but the answer to the discussion of 'infinite' maybe resolved (or at least move forward) if we recognize that 'infinite' is not one thing; there are different kinds of 'infinite'. See for example, numerable infinite vs innumerable infinite (also called countably infinite. vs uncountably infinite), and Cantor's distinctions and classic theorem of 'infinity of infinities'.
Hope this helps,
Itiel
Very true. No one's ever observed infinity. It's a hugely powerful concept, essential to the calculus, arguably the most significant development ever, after the concept of "zero," the concept of the infinitely small (can't see zero, either), where we can "approach" infinity, getting closer to zero distance, but never get there. And so often, when we try to get there, we run into that dang quantum uncertainty thing. (Number Theory was my favorite course.)
A Turing machine for gods: "Show me infinity." We probably wouldn't survive the demonstration.
Re: "Infinite Variation"
Posted: Wed Jan 06, 2010 12:53 pm
by briano
'To Infinity and Beyond'
Buzz Lightyear
Re: "Infinite Variation"
Posted: Thu Jan 07, 2010 6:12 am
by David Fairhurst
I too am unsure about where this topic came from or is giong to.
We must remember that the only variation we can use is variation between sources that can be reproduced and observed in a latent print and is persistent within the source. Beyond the magintude of a ridge unit the cellular, molecular, atomic and quantum structure of the skin is not persistent and cannot be determined from latent print anyway.
So, given where we came from and how we got here, where are we going with this?
Re: "Infinite Variation"
Posted: Thu Jan 07, 2010 8:28 am
by Gerald Clough
The topic has to do with two related issues. One is the claim, still made by some examiners, that their conclusion states an absolute reality that the person identified is the one and only individual capable of having made the impression. Regardless of opinions on what amount of information is sufficient to support a conclusion, this can only be true if every sufficient portion of friction ridge skin is unique, and a condition of absolute uniqueness is infinite variation. We have, from time to time, been at cross-purposes over what one or another meant by infinite variability. You accurately stated the fact that we don't have to worry about whether or not the skin is infinitely variable at some minute level, because, for our purposes, that skin consists only of the features we can observe in an impression.
This issue regularly also arises in discussions of application of probability to fingerprints, since, if one cannot hold that each and every possible fingerprint is unique, the likelihood of duplication is a very real interest, if such a thing can be determined. This may all seem obvious to you. Clearly, it doesn't become spontaneously obvious to everyone, nor, in fact, is it going to be accepted by everyone, for all sorts of reasons. Since this is a discussion group generally interested in developing ideas and sharing views, about the only thing that doesn't "go" anywhere is writing off those who differ with, "Oh. Those fools. Forget them." Even if they're challenged, they're all special here.

Re: "Infinite Variation"
Posted: Thu Jan 07, 2010 10:10 am
by kevin
lol! We're fingerprint examiners so there's room for all of us and our viewpoints on that bus

Re: "Infinite Variation"
Posted: Thu Jan 07, 2010 2:16 pm
by Pat A. Wertheim
kevin wrote:lol! We're fingerprint examiners so there's room for all of us and our viewpoints on that bus

With a high clearance and 4WD to get us through the quagmire!
Re: "Infinite Variation"
Posted: Thu Jan 07, 2010 4:36 pm
by Gerald Clough
Pat A. Wertheim wrote:kevin wrote:lol! We're fingerprint examiners so there's room for all of us and our viewpoints on that bus

With a high clearance and 4WD to get us through the quagmire!
What you can't see in the photo is the low-rider type air shocks to facilitate leaps of faith.