Humanist Discussion Group, Vol. 17, No. 181.
Centre for Computing in the Humanities, King's College London
www.kcl.ac.uk/humanities/cch/humanist/
www.princeton.edu/humanist/
Submit to: humanist@princeton.edu
[1] From: tgelder@trinity.unimelb.edu.au (182)
Subject: latest additions to Critical Thinking on the Web
[2] From: kotlas@email.unc.edu (22)
Subject: CIT Infobits -- july 2003
--[1]------------------------------------------------------------------
Date: Tue, 05 Aug 2003 06:12:10 +0100
From: tgelder@trinity.unimelb.edu.au
Subject: latest additions to Critical Thinking on the Web
21 July
in Textbooks
<http://www.as.wvu.edu/~sbb/comm221/primer.htm>Steve's Primer of Practical
Persuasion and Influence by Steve Booth-Butterfield
An online textbook on persuasion, influence and attitude. Developed for
use in a university course. Very "bare bones" (no pictures) but written in
a very accessible, colloquial style. [21 July 03]
18 July
in The Enlightenment
<http://www.nytimes.com/2003/07/12/opinion/12DENN.html>The Bright Stuff by
Daniel Dennett
Come out as a bright. "What is a bright? A bright is a person with a
naturalist as opposed to a supernaturalist world view. We brights don't
believe in ghosts or elves or the Easter Bunny or God." Being a bright is
not quite the same as being a critical thinker, but they are closely
aligned. (Yes, I count myself a bright.) [18 July 03]
5 July
in Guides
<http://vm.uconn.edu/~wwwphil/logic.pdf>A Quick Introduction to Logic by
Scott Lehmann
A 29 page document (pdf file) covering the basics of logic. Too succinct
and technical to be much use the first time you try to learn about logic,
but may be handy for someone wanting to refresh on core topics. [5 Jul 03]
24 Jun
in The Enlightenment (new section)
<http://www.boston.com/dailyglobe2/173/focus/Sweep_of_reason+.shtml>Sweep
of reason By Darrin M. McMahon
Reviewing the Encyclopedia of the Enlightenment is just the pretext for
this excellent, highly compact overview of the Enlightenment and reactions
to it. [24 Jun 03]
in Experts and Expertise - Literary Critics, and Language and Thought
<http://www.theatlantic.com/issues/2001/07/myers.htm>A Reader's Manifesto
by B.R. Myers.
Scathing attack on the sloppy thinking behind the pretentiously literary
style of today's acclaimed fiction, and on the goggle-eyed idiocy of
critics who applaud it. "Nothing gives me the feeling of having been born
several decades too late quite like the modern "literary" best
seller...Clumsy writing begets clumsy thought, which begets even clumsier
writing. The only way out is to look back to a time when authors had more
to say than "I'm a Writer!"; when the novel wasn't just a 300-page caption
for the photograph on the inside jacket." [24 Jun 03]
18 Jun
in Guides
Guide for the U.S. Customs Service Critical Thinking Skills Test (Word
document)
You may well find this useful even if you're not applying for promotion in
the US Customs Service. Much of the document consists of a fairly
technical introduction to basic logic. Working through this study guide
would probably be good preparation for a range of standard tests involving
logical thinking, eg the LSAT. [18 Jun 03]
14 Jun
in Language and Thought
<http://www.dc.com/bullfighter/>Bullfighter
"Stripping the bull out of business." This program works like a
spell-checker, but helps you remove consultant-speak (leverage, mindshare,
etc.) from your documents. From Deloitte Consulting, who were partly
responsible for creating the problem in the first place. At least they're
giving it away free. [14 Jun 03]
----------
Hans Farkas sent the following interesting query. It is not about critical
thinking as such, but it does involve applying critical thinking. Please
respond directly to Hans, hfarkas@yahoo.com
I would like to know if anyone has come across
information describing the fallacies of "ballistics
experts" testifying that they can positively identify
a gun via comparison of the markings on a test bullet
fired from that gun, and a bullet recovered from the
scene of the crime.
I have never seen a challenge to these claims, but
from what I know about how guns are manufactured,
specifically, how the rifling (i.e., grooves and
lands) is cut into the barrel, the "expert" claims of
being able to match a specific gun to a crime have got
to be wrong. Here's why.
The rifling is cut into the barrel via a hardened
cutter die, called a button, which has the design
ground into it, and when it is pulled or pressed
through the barrel's smooth bore, it cuts the high
and low spirals (called rifling) into the barrel. Now
this cutter die (i.e., button) is either made from
hardened tool steel, or perhaps tungsten carbide. At
any rate, the same button is used to cut the rifling
into many barrels. How many times a specific button
can be used before it is worn out depends on a number
of factors, and a tungsten carbide cutter will last
considerably longer than a tool steel cutter.
But certainly a significant number of barrels are
rifled by the same button. And the number of barrels
a specific button can rifle is probably in the
hundreds, and perhaps even in the thousands, before it
has to be replaced.
What this means is that essentially all the barrels of
a specific manufacturing run that are cut by the same
button, are going to have the same rifling pattern.
Undoubtedly, assuming that the same button can be used
on 1,000 barrels, there might be a microscopic
difference in the sharpness of the cut when comparing
the first barrel with the thousandth one. But surely
there is no practically distinguishable difference
between between the first 100 barrels with each other,
or between the last hundred with each other. In other
words, while one might distinguish a microscopic
difference between the first barrel as compared to
barrel number 999, surely the difference between the
first barrel and the second barrel, etc., are
virtually indistinguishable.
If this is true, then the "experts" claiming that a
positive identification was made are actually only
able to say (in the best case, assuming they have made
a careful comparison) that the bullet recovered at the
scene of the crime probably came from a gun
manufactured by the same button as the gun in
question. In other words, instead of claiming it is
the same gun, they are only able to state (if they are
honest and competent) that one of hundreds of guns
from the same manufacturing run could be the actual
gun. Furthermore, it is probable that even if
multiple buttons are used in a specific manufacturing
run (i.e., same model and year of manufacture), each
button is made to the same close tolerances and
design. This would make it impossible to distinguish
the grooves made even from a group of buttons, from
each other, certainly by the relatively crude methods
of comparison (low-power microscopic alignment of
rifling) used by these experts.
Realistically, it is one thing to distinguish between
a bullet from a Smith & Wesson 38 caliber, from a Colt
38 caliber since each manufacture is making his own
buttons, undoubtedly to different designs. And
probably different models of the same caliber from the
same manufacture, or from different years of
manufacture are distinguishable. But to distinguish
between any one of a thousand barrels rifled by the
same button is probably not possible in the way these
"experts" do their comparison. Undoubtedly on a
theoretical basis, say with very high magnifications
of electron microscopes it might be possible to
actually distinguish, for example barrel number 48
from barrel number 49, by seeing extremely minute
changes in the button due to wear. But that is not
how these "experts" practice their craft.
It is one thing to use this type of comparison to
exclude a gun, but quite another to be able to state
with certainty it is the same gun. For example, if
the gun is a 38 caliber and the bullet recovered from
the crime scene is a 44 caliber, it is easy to be
certain that they are mutually exclusive. Similarly,
in the case of the same caliber comparison, if the
rifling does not match (perhaps because the grooves
are of a different number, or the depths are
different, or the widths differ), exclusion can be
done with certainty. But if everything matches, the
best that can be stated is that they are similar
enough to be from the same make and model, or even
from the same manufacturing run. But that may mean
there are thousands of other guns from that make,
model, caliber and year that are essentially
identical. But where is the expert that ever states
such caveats?
With DNA analysis, we used to hear that either a
suspect was cleared because the markers didnt match,
or that there was a 1 in 50,000 (or 1 in 10,000,000,
etc.,) chance that this was indeed the guilty person.
Of course this also meant that, however remote, a
certain number of other individuals would also match
the DNA evidence. But we dont hear such things from
the ballistics experts.
But has anyone actually come across information to
validate these shortcomings? If so, please let me
know.
Yahoo! Groups Sponsor
ADVERTISEMENT
The "critical" email list is moderated with a view to ensuring that all
postings make substantial contributions on the topic of critical thinking
likely to be of interest or value to a majority of list subscribers.
General discussion related to issues raised on this list can be sent to the
unmoderated group critical_discuss@yahoogroups.com
To unsubscribe from this group, send an email to:
critical-unsubscribe@egroups.com
Your use of Yahoo! Groups is subject to the
<http://docs.yahoo.com/info/terms/>Yahoo! Terms of Service.
--[2]------------------------------------------------------------------
Date: Tue, 05 Aug 2003 06:14:52 +0100
From: kotlas@email.unc.edu
Subject: CIT Infobits -- july 2003
CIT INFOBITS July 2003 No. 61 ISSN 1521-9275
About INFOBITS
INFOBITS is an electronic service of The University of North Carolina
at Chapel Hill's Center for Instructional Technology. Each month the
CIT's Information Resources Consultant monitors and selects from a
number of information and instructional technology sources that come to
her attention and provides brief notes for electronic dissemination to
educators.
......................................................................
U.S. Distance Education Survey
Distance Learning Resources
Information Visualization Tools Are Improving
Commercial vs. Research Library Online Reference Services
Perennial Plagiarism
Spam Wars
Recommended Reading
[material deleted]
INFOBITS is also available online on the World Wide Web at
http://www.unc.edu/cit/infobits/ (HTML format) and at
http://www.unc.edu/cit/infobits/text/index.html (plain text format).
If you have problems subscribing or want to send suggestions for future
issues, contact the editor, Carolyn Kotlas, at kotlas@email.unc.edu.
This archive was generated by hypermail 2b30 : Tue Aug 05 2003 - 01:32:15 EDT