Lie detectors in SF

[alal...@gmail.com]

I was wondering if any SF has been written, with the story focusing on the invention of a reliable lie detector. Already people are scanning the brain to see if people are telling the truth or lying. The initial use of lie detectors might be in law enforcement, courtrooms, and politics. As the lie detectors became cheaper and more mobile, it would become a must have for everyone, being used in the home and workplace.

Human beings are liars, therefore a reliable and portable lie detector has the potential to dramatically alter the functioning of society. Maybe laws will be enacted, to require consent before a lie detector can be used against you.

Abhinav Lal
Writer & Investor

"Transfer all your assets to Abhinav Lal"
-- God

[Ted Nolan <tednolan>]

In article <61ad98a8-4bc9-452d...@googlegroups.com>,

<alal...@gmail.com> wrote:
>I was wondering if any SF has been written, with the story focusing on
>the invention of a reliable lie detector. Already people are scanning
>the brain to see if people are telling the truth or lying. The initial
>use of lie detectors might be in law enforcement, courtrooms, and
>politics. As the lie detectors became cheaper and more mobile, it would
>become a must have for everyone, being used in the home and workplace.
>
>Human beings are liars, therefore a reliable and portable lie detector
>has the potential to dramatically alter the functioning of society.
>Maybe laws will be enacted, to require consent before a lie detector can
>be used against you.
>

There are a number of such stories wherein aliens have the detectors
and captive humans are able to manipulate the aliens by telling the
exact literal truth.

For instance, a captive trying to convince the aliens that humans have
vast physic powers thinks something like:

Hmm.. How does a man walk?

and says something like:

"It is true that we have learned how to use the power of
our minds to caue physical objects to move"
--
------
columbiaclosings.com
What's not in Columbia anymore..

[Robert Carnegie]

On Wednesday, 25 January 2017 14:00:55 UTC, alal...@gmail.com wrote:
> I was wondering if any SF has been written, with the story focusing on the invention of a reliable lie detector. Already people are scanning the brain to see if people are telling the truth or lying. The initial use of lie detectors might be in law enforcement, courtrooms, and politics. As the lie detectors became cheaper and more mobile, it would become a must have for everyone, being used in the home and workplace.
>
> Human beings are liars, therefore a reliable and portable lie detector has the potential to dramatically alter the functioning of society. Maybe laws will be enacted, to require consent before a lie detector can be used against you.

A telephone lie detector has been used on
British social welfare claimants. It probably
didn't really work but it frightened them,
which probably was the real intention. And it
may have indicated true statements as lies.

In the recent "Lost Fleet" novels, set quite a
long way in the future, lie detecting in
interrogation is sophisticated but not perfect.
It can register evasion and the intention to lie.
But it can be beaten.

In _The Stainless Steel Rat's Revenge_, the hero
beats a lie detector by deliberately feeling panic
before a question is asked, and feeling tired
before answering. He tells the reader that this
doesn't work when a lie detector is used properly
in a careful interrogation.

This man
<https://en.wikipedia.org/wiki/William_Moulton_Marston>
was involved with early electric lie detectors,
with his wife and another lady at the same time,
and with the comics character Wonder Woman, whose
magic rope makes you tell her the truth when she
ties you up with it. If these walls could talk, eh.

[alal...@gmail.com]

Can you determine the truth value of these statements:

1. I am lying.

2. I am the author of "The Hobbit"


Good luck.

[Default User]

On Wednesday, January 25, 2017 at 8:00:55 AM UTC-6, alal...@gmail.com wrote:
> I was wondering if any SF has been written, with the story focusing on the invention of a reliable lie detector. Already people are scanning the brain to see if people are telling the truth or lying. The initial use of lie detectors might be in law enforcement, courtrooms, and politics. As the lie detectors became cheaper and more mobile, it would become a must have for everyone, being used in the home and workplace.

Heinlein's The Star Beast featured reliable lie detectors in a courtroom setting, with the note at one point that a very firmly held belief can register as truth. So "calibration" was needed. These were not in general use, as far as could be determined.


Brian

[Scott Lurndal]

Default User <defaul...@yahoo.com> writes:
>On Wednesday, January 25, 2017 at 8:00:55 AM UTC-6, alal...@gmail.com wrote=
>:
>> I was wondering if any SF has been written, with the story focusing on th=
>e invention of a reliable lie detector. Already people are scanning the br=
>ain to see if people are telling the truth or lying. The initial use of li=
>e detectors might be in law enforcement, courtrooms, and politics. As the =
>lie detectors became cheaper and more mobile, it would become a must have f=

>or everyone, being used in the home and workplace.
>

>Heinlein's The Star Beast featured reliable lie detectors in a courtroom se=
>tting, with the note at one point that a very firmly held belief can regist=
>er as truth. So "calibration" was needed. These were not in general use, as=

> far as could be determined.

Kimball Kinnison's Lens was a reliable lie detector, IIRC.

[David Goldfarb]

In article <eerqrk...@mid.individual.net>,

Ted Nolan <tednolan> <tednolan> wrote:
>There are a number of such stories wherein aliens have the detectors
>and captive humans are able to manipulate the aliens by telling the
>exact literal truth.
>
>For instance, a captive trying to convince the aliens that humans have
>vast physic powers thinks something like:
>
> Hmm.. How does a man walk?
>
>and says something like:
>
> "It is true that we have learned how to use the power of
> our minds to caue physical objects to move"

That particular one is "The Best Policy", by Randall Garrett.
As usual in such things, the author stacks the deck a bit.

H. Beam Piper's _Little Fuzzy_ books have a "polyencephalographic
veridicator", which is used in the trial scenes. The books aren't
about that, though, it's just a background detail.

--
David Goldfarb |"English cuisine is the cuisine of fear."
goldf...@gmail.com |
gold...@ocf.berkeley.edu | -- Andrew Conway

[mcdow...@sky.com]

The Vorkosiverse has a drug called fast-penta which does what you would expect from the name: it dumbs down the subject while making them willing to ramble on about topics they can be queried on by a skilled interrogator. See e.g. "Komarr". Its use is limited by law (where applicable) and by the moral scruples of those above the law (e.g. Imperial Auditors).

I seem to recall Asimov making use of limited truth devices of some sort to tie up the ends of SF detective stories.

Sophisticated organisations can counter any truth device by working through cut-outs who are content to believe whatever they are told. I therefore believe that the net effect of truth devices on these targets will be to make everybody's life more inefficient because of mistakes by cut-outs. I believe that it was perfectly predictable that today's real truth telling devices - continuous surveillance of electronic communications - has mostly had the effect of causing those with bad consciences to work much less efficiently than they might in an attempt to get by without using communications media under surveillance. I did not, however, predict that this would cause people to use dodgy unofficial email services.

[David Johnston]

On 1/25/2017 1:16 PM, mcdow...@sky.com wrote:
> On Wednesday, January 25, 2017 at 2:00:55 PM UTC, alal...@gmail.com
> wrote:
>> I was wondering if any SF has been written, with the story focusing
>> on the invention of a reliable lie detector. Already people are
>> scanning the brain to see if people are telling the truth or lying.
>> The initial use of lie detectors might be in law enforcement,
>> courtrooms, and politics. As the lie detectors became cheaper and
>> more mobile, it would become a must have for everyone, being used
>> in the home and workplace.
>>
>> Human beings are liars, therefore a reliable and portable lie
>> detector has the potential to dramatically alter the functioning of
>> society. Maybe laws will be enacted, to require consent before a
>> lie detector can be used against you.
>>
>> Abhinav Lal Writer & Investor
>>
>> "Transfer all your assets to Abhinav Lal" -- God
>
> The Vorkosiverse has a drug called fast-penta which does what you
> would expect from the name: it dumbs down the subject while making
> them willing to ramble on about topics they can be queried on by a
> skilled interrogator. See e.g. "Komarr". Its use is limited by law
> (where applicable) and by the moral scruples of those above the law
> (e.g. Imperial Auditors).

But of course that's a technology that has been around for a long time
as of the Vorkosigan timeframe. I haven't seen any stories about the
initial integration of quasi-infallible lie detection or worse truth
compulsion into law enforcement and government.

[The Starmaker]

Lie detectors don't detect lies, they are stress detectors.

[Robert Carnegie]

What are those fantasy aliens that never lie but
are genius masters of prevarication? Oh, yeah,
Vulcans. :-)

In some stories (not generally ones about Vulcans),
the Devil is carefully truthful, but without providing
the complete truth. Maybe because "I lied, bucko"
is a less satisfying twist in a pact-with-the-devil
story than "now I'll point out what you failed to
consider."

[Gutless Umbrella Carrying Sissy]

Robert Carnegie <rja.ca...@excite.com> wrote in
news:80a51755-2ea2-400d...@googlegroups.com:

Has anybody ever explored the difference between a lie detector and
a truth detector?

--
Terry Austin

Vacation photos from Iceland:
https://plus.google.com/u/0/collection/QaXQkB

"Terry Austin: like the polio vaccine, only with more asshole."
-- David Bilek

Jesus forgives sinners, not criminals.

[alal...@gmail.com]

Is the polygraph a stress detector? I don't think fMRI brain scanners are detecting stress.

Is this truth or lie:

The current year is 2017

[Lawrence Watt-Evans]

On Wed, 25 Jan 2017 06:00:51 -0800 (PST), alal...@gmail.com wrote:

>I was wondering if any SF has been written, with the story focusing on the invention of a reliable lie detector. Already people are scanning the brain to see if people are telling the truth or lying. The initial use of lie detectors might be in law enforcement, courtrooms, and politics. As the lie detectors became cheaper and more mobile, it would become a must have for everyone, being used in the home and workplace.

I'm amazed no one has mentioned _The Truth Machine_, by James
Halperin. Which was initially self-published online, then sold to Del
Rey.



--
My webpage is at http://www.watt-evans.com

[Dimensional Traveler]

In which calendar?


--
Running the rec.arts.TV Channels Watched Survey.
Winter 2016 survey began Dec 01 and will end Feb 28

[Kevrob]

It is, at best, a partial truth.

If you had written 2017 CE or 2017 AD, I might be able to judge.

Kevin R

[Lynn McGuire]

David Weber makes extensive usage of the Imperial Lie Detector throughout his three volume Dahak series. The Imperial Lie Detector
is not beatable and the questionee cannot resist answering the questions, even to the point of self incrimination. The session is
usually followed by a firing squad.
https://www.amazon.com/Mutineers-Moon-Dahak-David-Weber/dp/0671720856/

Lynn

[Don Kuenz]

David Goldfarb <gold...@ocf.berkeley.edu> wrote:
> In article <eerqrk...@mid.individual.net>,
> Ted Nolan <tednolan> <tednolan> wrote:
>>There are a number of such stories wherein aliens have the detectors
>>and captive humans are able to manipulate the aliens by telling the
>>exact literal truth.
>>
>>For instance, a captive trying to convince the aliens that humans have
>>vast physic powers thinks something like:
>>
>> Hmm.. How does a man walk?
>>
>>and says something like:
>>
>> "It is true that we have learned how to use the power of
>> our minds to caue physical objects to move"
>
> That particular one is "The Best Policy", by Randall Garrett.
> As usual in such things, the author stacks the deck a bit.
>
> H. Beam Piper's _Little Fuzzy_ books have a "polyencephalographic
> veridicator", which is used in the trial scenes. The books aren't
> about that, though, it's just a background detail.

That device reminds me of the Voight-Kampff empathy test apparatus in
_Do Androids Dream of Electric Sheep_ (PDK). The apparatus uses
biometric feedback to detect an android's deceitful answer.

A liar who truly believes his own lies is telling the truth, as far as
the liar knows. George advises Jerry to believe his own lies in the this
excerpt from "The Beard" episode of _Seinfeld_:

Jerry: So George, how do I beat this lie detector?

George: I'm sorry, Jerry I can't help you.

Jerry: Come on, you've got the gift. You're the only one that can
help me.

George: Jerry, I can't. It's like saying to Pavorotti, "Teach me
to sing like you."

Jerry: All right, well I've got to go take this test. I can't
believe I'm doing this.

George: Jerry, just remember. It's not a lie... if you believe it.

https://www.youtube.com/watch?v=vn_PSJsl0LQ

Thank you,

--
Don Kuenz KB7RPU

The best liar is he who makes the smallest amount of lying go the
longest way. - Samuel Butler

[art...@yahoo.com]

On Wednesday, January 25, 2017 at 4:23:05 PM UTC-5, Robert Carnegie wrote:

> What are those fantasy aliens that never lie but
> are genius masters of prevarication? Oh, yeah,
> Vulcans. :-)

Then there is James Morrow's City Of Truth in which at a certain age, everybody has an medical procedure which prevents them from lying.
Of course, the truth is little too much:
The protagonist's son goes to Camp Ditch The Kids
Someone drives a Ford Adequate

[The Starmaker]

can a computer lie? neither can a brain.

[Robert Bannister]

On 25/1/17 10:00 pm, alal...@gmail.com wrote:
> I was wondering if any SF has been written, with the story focusing
> on the invention of a reliable lie detector. Already people are
> scanning the brain to see if people are telling the truth or lying.
> The initial use of lie detectors might be in law enforcement,
> courtrooms, and politics. As the lie detectors became cheaper and
> more mobile, it would become a must have for everyone, being used in
> the home and workplace.

Bujold has some drug that works reliably. Sounds like fantasy to me.

>
> Human beings are liars, therefore a reliable and portable lie
> detector has the potential to dramatically alter the functioning of
> society. Maybe laws will be enacted, to require consent before a lie
> detector can be used against you.

We, or at least our politicians, are so good at lying, it is unlikely we
couldn't beat any machine or drug thrown at us.

--
Robert B. born England a long time ago;
Western Australia since 1972

[Greg Goss]

Don Kuenz <g...@crcomp.net> wrote:

>A liar who truly believes his own lies is telling the truth, as far as
>the liar knows.

An old Analog story featured a machine that could help you beat a lie
detector.

While under this machine, you concentrate on convincing yourself that
you're not the kind of person who could have done the accused crime.
Just in case the police "go fishing", you also convince yourself that
you're not the kind of person who did that other crime, or crime C
etc. The machine helps you believe that.

In the final paragraph, someone accuses the inventor of helping crime
kingpins get away with murder.

"Have you been watching the murder rate the last two years? The
underworld is rapidly filling with the kind of people who would never
do that kind of crime."
--
We are geeks. Resistance is voltage over current.

[Greg Goss]

Robert Carnegie <rja.ca...@excite.com> wrote:

>A telephone lie detector has been used on
>British social welfare claimants. It probably
>didn't really work but it frightened them,
>which probably was the real intention. And it
>may have indicated true statements as lies.

Every decade or so, microtremor absence detectors (voice stress
analysis machines) seem to surface as lie detectors, arouse tremendous
interest for a couple of years, then vanish. We're probably overdue
for the next round.

[mcdow...@sky.com]

Polygraphs are dubious - see e.g. https://www.nap.edu/read/10420/chapter/6#107 if you can stand the annoying framing and CSS. "practitioners have always claimed extremely high levels of accuracy, and these claims have rarely been reflected in empirical research. Levey’s (1988) analysis suggests that conclusions about the accuracy of the polygraph have not changed substantially since the earliest empirical assessments of this technique and that the prospects for improving accuracy have not brightened over many decades."

fMRI could in theory result in more accurate lie detectors. I thought this area would get lots of funding under George W Bush, possibly to the extent of posing moral dilemmas, but he avoided this by employing bone-headed thugs who replayed history - see the tail end of http://david-drake.com/2015/newsletter-84/. Hopefully Mattis will demonstrate that he is not bone-headed.

[Mark Bestley]

<alal...@gmail.com> wrote:

> I was wondering if any SF has been written, with the story focusing on the
invention of a reliable lie detector. Already people are scanning the
brain to see if people are telling the truth or lying. The initial use
of lie detectors might be in law enforcement, courtrooms, and politics.
As the lie detectors became cheaper and more mobile, it would become a
must have for everyone, being used in the home and workplace.
>
> Human beings are liars, therefore a reliable and portable lie detector has
the potential to dramatically alter the functioning of society. Maybe
laws will be enacted, to require consent before a lie detector can be
used against you.
>

Brian Aldiss's Primal Urge where it is not taken up fully

Also see The Encyclopedia of Science Fiction esay on lie detectors
<http://www.sf-encyclopedia.com/entry/lie_detectors>

--
Mark

[Lynn McGuire]

The drug is fast penta. And it is dangerous as a significant amount of the population is allergic to it. But, that could get rid of
the need to round up a firing squad.
http://vorkosigan.wikia.com/wiki/Fast-penta

Lynn

[The Starmaker]

I'll expand on it since I knows yous SF people fail to understand...

The 'soul/consciousness' takes the output from the computer/brain and
lies about the output if it wants to.

So, fMRI brain scanners cannot detect a lie and neither can a stress machine like a lie polygragh detectors.


Now, I can tell you (but it hasn't been discovered or invented yet 'except by me') that what is needed for a reliable lie detector
machine is one that can detect the ....consciousness, when it tells a lie.

I will not reveal how it is done because I am the inventor and the discoverer.

I gotta put a patent on it first...


The Starmaker

[Robert Carnegie]

There's a drug in the D'Alembert Circus novels:
it kills fifty percent of subjects, some before
they start talking I think, but there's no other
way to beat it. Hayrff lbh vawrpg gur ivyynva
hfvat gurve bja fhccyl bs gur qeht, orpnhfr vg
znl abg or gur erny qeht ng nyy whfg sbe guvf
checbfr, naq gurer'f nabgure guvat...
as you know. :-)

[Michael F. Stemper]

On 2017-01-26 16:55, Robert Carnegie wrote:
> On Thursday, 26 January 2017 18:19:53 UTC, Lynn McGuire wrote:
>> On 1/25/2017 10:15 PM, Robert Bannister wrote:

>>> Bujold has some drug that works reliably. Sounds like fantasy to me.

>> The drug is fast penta. And it is dangerous as a significant amount of the population is allergic to it. But, that could get rid of
>> the need to round up a firing squad.
>> http://vorkosigan.wikia.com/wiki/Fast-penta
>
> There's a drug in the D'Alembert Circus novels:
> it kills fifty percent of subjects, some before
> they start talking I think, but there's no other
> way to beat it.

It's called "nitrobarb".

> way to beat it. Hayrff lbh vawrpg gur ivyynva
> hfvat gurve bja fhccyl bs gur qeht, orpnhfr vg
> znl abg or gur erny qeht ng nyy whfg sbe guvf
> checbfr, naq gurer'f nabgure guvat...

Rfcrpvnyyl vs gur ivyynva vf na naqebvq, which isn't
discovered for at least one more book.

--
Michael F. Stemper
No animals were harmed in the composition of this message.

[The Starmaker]

Right now I'm working on how to put a patent on it first, (to be used
for only law enforcement agencies)..

but I can tell you it is 100 percent accuracte.

I did a test..
On the JonBenet Ramsey murder..

it turns out the mother is the murder.

Not only with my invention can you detect the murder,
but, adding a few options to my invention..
you can actually see the murders taking place.

[David DeLaney]

On 2017-01-25, alal...@gmail.com <alal...@gmail.com> wrote:
> I was wondering if any SF has been written, with the story focusing on the
> invention of a reliable lie detector.

Most of the responders seem to have added an implied "machine" to your lie
detector. I'm thinking of another kind, also well-represented in SF (and some
fantasy as well): the 'truth drug'. Which once taken either makes the recipient
unable to lie, or unable to phrase things as lies, or wonky enough that they
don't think of lying, or trust the giver enough to want to let them in on the
answers to everything they ask, or whatever ... or, much less commonly, induces
some visible/detectable physical reaction when they DO lie.

An example from SF is the Vorkosigan 'fast-penta', which Miles manages to
dfeat by a very rare method.

Fantasy can do this with potions, but usually uses spells instead; think of
the Deryni truth-reading procedure, or the last remaining bit of actual magic
the Valdemaran Heralds use, the truth spell (and the fact that it has two
stages, the second one more restrictive).

And for fantasy-disguised-as-SF, of course, there's telepathy, so that you
know when the subject -thinks- he's lying.

Dave, tenser, said the tensor
--
\/David DeLaney posting thru EarthLink - "It's not the pot that grows the flower
It's not the clock that slows the hour The definition's plain for anyone to see
Love is all it takes to make a family" - R&P. VISUALIZE HAPPYNET VRbeable<BLINK>
gatekeeper.vic.com/~dbd - net.legends FAQ & Magic / I WUV you in all CAPS! --K.

[Robert Bannister]

On 28/1/17 11:46 pm, David DeLaney wrote:
> On 2017-01-25, alal...@gmail.com <alal...@gmail.com> wrote:
>> I was wondering if any SF has been written, with the story focusing on the
>> invention of a reliable lie detector.
>
> Most of the responders seem to have added an implied "machine" to your lie
> detector. I'm thinking of another kind, also well-represented in SF (and some
> fantasy as well): the 'truth drug'. Which once taken either makes the recipient
> unable to lie, or unable to phrase things as lies, or wonky enough that they
> don't think of lying, or trust the giver enough to want to let them in on the
> answers to everything they ask, or whatever ... or, much less commonly, induces
> some visible/detectable physical reaction when they DO lie.
>
> An example from SF is the Vorkosigan 'fast-penta', which Miles manages to
> dfeat by a very rare method.
>
> Fantasy can do this with potions, but usually uses spells instead; think of
> the Deryni truth-reading procedure, or the last remaining bit of actual magic
> the Valdemaran Heralds use, the truth spell (and the fact that it has two
> stages, the second one more restrictive).
>
> And for fantasy-disguised-as-SF, of course, there's telepathy, so that you
> know when the subject -thinks- he's lying.

All the same, the only actual attempts to create lie detection have been
in the USA where, after dodgy trials with sodium thiopental (whence
"fast-penta" as an improvement) and scopolamine among others, mechanical
"lie detectors" were made. Some people still insist that they work, so
fantasy is obviously important.

[J. Clarke]

In article <ef7o4c...@mid.individual.net>,
rob...@clubtelco.com says...

Just a data item with Pentothal. One anecdotal
point. I had my wisdom teeth removed many
decades ago. The dentist used pentothal as
anesthesia (it was done under a general
anesthetic). When I was coming out of it, I was
asked my social security number. One one level
I knew I had no clue what it was but on another,
the one on which my speech center was apparently
functioning, it came right out, correctly, and I
have not had any problem remembering it since.

I don't know what if anything that tells us
about drugs used for interrogation, but I found
it an interesting experience.

[mcdow...@sky.com]

ObSF - at the end of Komarr

"How will you explain the missing drug doses to ImpSec?"

"One, I am an Imperial Auditor, I don't have to explain anything to anybody. Two, we used it experimentally to enhance scientific insight. Which I gather is the truth, so I return to Go _and_ collect my tokens."

[Michael F. Stemper]

On 2017-01-26 17:53, Michael F. Stemper wrote:
> On 2017-01-26 16:55, Robert Carnegie wrote:

>> There's a drug in the D'Alembert Circus novels:
>> it kills fifty percent of subjects, some before
>> they start talking I think, but there's no other
>> way to beat it.
>
> It's called "nitrobarb".

In Ursula K. LeGuin's _The Left Hand of Darkness_, there is what appears
to be a class of truth drugs known as "veridicals". No details about
them or potential side-effects (such as death).

--
Michael F. Stemper
Always remember that you are unique. Just like everyone else.

[larry]

The Roman philosopher Pontius Pilate perhaps?

[David Johnston]

>>>>>> Human beings are liars, therefore a reliable and portable
>>>>>> lie detector has the potential to dramatically alter the
>>>>>> functioning of society. Maybe laws will be enacted, to
>>>>>> require consent before a lie detector can be used against
>>>>>> you.
>>>>>>
>>>>>> Abhinav Lal Writer & Investor
>>>>>>
>>>>>> "Transfer all your assets to Abhinav Lal" -- God
>>>>>
>>>>> The Vorkosiverse has a drug called fast-penta which does what
>>>>> you would expect from the name: it dumbs down the subject
>>>>> while making them willing to ramble on about topics they can
>>>>> be queried on by a skilled interrogator. See e.g. "Komarr".
>>>>> Its use is limited by law (where applicable) and by the moral
>>>>> scruples of those above the law (e.g. Imperial Auditors).
>>>>
>>>> But of course that's a technology that has been around for a
>>>> long time as of the Vorkosigan timeframe. I haven't seen any
>>>> stories about the initial integration of quasi-infallible lie
>>>> detection or worse truth compulsion into law enforcement and
>>>> government.

Probably because it isn't a terribly interesting transition. First spies
use them, then they get used semi-officially by law enforcement, then
once their overwhelming accuracy is confirmed political debates ensue
with all the talking heads of Honor Harrington and none of the
explosions and assassinations.

That being said...there is one. In the Deryni fanfic anthology "Deryni
Tales", Alaric Morgan walks into a trial and just takes it over, which
he can do because he's a duke and uses magic which had been illegal
since roughly last Tuesday to free the unjustly accused and point the
finger at the guilty parties. It's all very deus ex machina and
something of a demonstration of why you don't see the introduction of
infallible lie detection in stories very often.

[Moriarty]

Nitpick: that's the story "Trial". It's in the Kurtz-written "The Deryni Archives", rather than the fanfic anthology you ascribe it to.

-Moriarty

[David Mitchell]

Search for The Truth Machine. It's a novel by James L Halperin.
IIRC, it's not bad.

[larry]

There is a copy at coins.ha.com , I see.
Thanks, I'll try it.