Fixing Time For The Stars
Howard Brazee
don't remember how much acceleration was in most of the trip - anybody
remember?
At any rate - how do we fix Time For The Stars, keeping the premise of
instantaneous twin communication?
Dorothy J Heydt
Um ... how about fixing instantaneous twin communication first?
Not to mention marriage WELL within the forbidden degrees of
consanguinity.
--
Dorothy J. Heydt
Vallejo, California
djheydt at gmail dot com
Should you wish to email me, you'd better use the gmail edress.
Kithrup's all spammy and hotmail's been hacked.
Tim Little
> In article <kiai26dn8p72hlhpl...@4ax.com>,
> Howard Brazee <how...@brazee.net> wrote:
>>At any rate - how do we fix Time For The Stars, keeping the premise of
>>instantaneous twin communication?
>
> Um ... how about fixing instantaneous twin communication first?
Yes, that is really the big problem for Relativity.
> Not to mention marriage WELL within the forbidden degrees of
> consanguinity.
What? That's perfectly consistent with "Special Relatives".
- Tim
Derek Lyons
>Not to mention marriage WELL within the forbidden degrees of
>consanguinity.
That depends on who is doing the forbidding doesn't it?
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Erik Max Francis
> Heinlein's Time For The Stars doesn't fit Special Relativity.
Care to hum a few bars?
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
To lead an uninstructed people to war is to throw them away.
-- Confucius, ca. 6th C. BC
Dorothy J Heydt
That must be a very clever pun, but I don't get it.
Jonathan Schattke
> Heinlein's Time For The Stars doesn't fit Special Relativity. I
> don't remember how much acceleration was in most of the trip - anybody
> remember?
If I recall correctly, the acceleration was 1G for most of the trip. I
think R.A.H. did the calcs for that, assuming some magical reaction drive.
The "problem" is that the traveling twin perceives his stationary twin
as speeding up, using instant communication. If you work out the
implications of instant communication, you will find this is exactly
what must happen. The paradoxical special relativity result of observer
and traveler both seeing the other slow is due to light speed delays.
> At any rate - how do we fix Time For The Stars, keeping the premise of
> instantaneous twin communication?
You don't. You assume R.A.H. could think and knew the science.
Wayne Throop
: Heinlein's Time For The Stars doesn't fit Special Relativity. I don't
Not sure what would fix it. The instantaneous communication thing
seems pretty hard to retain, and keep special relativity. But if
it's kept... then there'd need to be scenes showing that simultaneity
(and thus instantaneous-ness) is relative, not absolute. And that each
twin thinks the other one is slowing down (though the stay-at-home
slows down a bit more), until turnover. Presuming the physics of
instantaneousness is as per Rindler coordinates, and that I'm visualizing
the axis rotations correctly.
Note that you quickly get a situation where you can receive a reply
to a message before you send it.
Now, iirc, if you want to fix the time rate issues and keep an absolute
standard of simultaneity (ie, rejecting relativity of simultaneity,
hence rejecting one of the most important issues of special relativity,
what with it being the very first relativistic gedanken published), you no
longer have decades worth of time difference for survivable accelerations.
You either have to add magic inertial compensation (as Anderson did in
Tau Zero), or put up with less time differences to the nearer stars.
Wayne Throop thr...@sheol.org http://sheol.org/throopw
Wayne Throop
: The "problem" is that the traveling twin perceives his stationary twin
: as speeding up, using instant communication. If you work out the
: implications of instant communication, you will find this is exactly
: what must happen. The paradoxical special relativity result of
: observer and traveler both seeing the other slow is due to light speed
: delays.
IMO it is extremely misleading to say it's "due to" lightspeed delays.
Because the symmetry of the effect still occurs if one reckons clock
ticks with coordinates with lightspeed delay removed. Or put another
way, the symmetry of time dilation is "due to" the lorentz transform
(in the sense of being derivable from it), and lightspeed delay has
nothing at all to do with the lorentz transform.
Dorothy J Heydt
Jonathan Schattke <wiz...@gmail.com> wrote:
>On 6/28/2010 6:06 PM, Howard Brazee wrote:
>> Heinlein's Time For The Stars doesn't fit Special Relativity. I
>> don't remember how much acceleration was in most of the trip - anybody
>> remember?
>
>If I recall correctly, the acceleration was 1G for most of the trip. I
>think R.A.H. did the calcs for that, assuming some magical reaction drive.
On huge sheets of butcher paper spread all over the kitchen
table? Possibly.
Wayne Throop
:: reaction drive.
: djh...@kithrup.com (Dorothy J Heydt)
: On huge sheets of butcher paper spread all over the kitchen table?
: Possibly.
Assuming he did calculate, I wonder if he calculated based on the
assumption that the acceleration remained 1g in the original rest frame.
Or something. Because I think the book contains time rate discrepancies
quite a lot larger than a 1-g-in-instantaneously-comoving-frame would
imply. But I haven't gone back to check numerically...
But... it'd still be interesting to know exactly what the OP thought
needed fixing. Especially since a reveal towards the end of the book
is that relativity is Just Plain Wrong. So, making the various effects
consistent with relativity seems pretty moot.
Greg Goss
>Heinlein's Time For The Stars doesn't fit Special Relativity. I
>don't remember how much acceleration was in most of the trip - anybody
>remember?
Did they use 1 G accelleration all the time, or did they blast up to
relativistic speed then spin the ship?
The Ortega torchships in TFTS are descended from the rocket-powered
ships of Farmer In The Sky, where the room fittings were moved from
one wall to another when the ship switched from boosting to spinning.
>At any rate - how do we fix Time For The Stars, keeping the premise of
>instantaneous twin communication?
The whole point of relativity is that you don't KNOW which twin is
moving. "Simultaneous" is meaningless under relativity.
--
Tomorrow is today already.
Greg Goss, 1989-01-27
Carey
> In article <kiai26dn8p72hlhpl...@4ax.com>,
> Howard Brazee <how...@brazee.net> wrote:
>> Heinlein's Time For The Stars doesn't fit Special Relativity. I
>> don't remember how much acceleration was in most of the trip - anybody
>> remember?
>>
>> At any rate - how do we fix Time For The Stars, keeping the premise of
>> instantaneous twin communication?
>
> Um ... how about fixing instantaneous twin communication first?
>
> Not to mention marriage WELL within the forbidden degrees of
> consanguinity.
She was his great grandniece I believe?
First off, this means she is not a direct descendant (which disqualifies
a couple for marriage in California regardless of the number of
generations).
Looking at the matter genetically, psychic-space-guy has a 1/2 chance of
inheriting a lethal recessive from one of his parents, while
psychic-Earth-GGNiece has a 1/16 chance. Their children have a 1/4
chance of getting said gene from Dad and a 1/32 chance from Mom, so they
have a 1/128 chance overall.
This is a degree of genetic risk roughly midway between second and third
cousin marriage. Second cousin marriage is allowed everywhere in the
world, and third cousins actually have a better-than-normal fertility
rate. (Even first cousin marriage being widely outlawed is unique to the
U.S., it is allowed most everywhere else and is common in some cultures.)
So - Heinlein did his homework here too.
Erik Max Francis
It's simpler than that. He's used the phrase "instant communication."
Never mind that faster-than-light travel/communication is a no-no in
special relativity unless you want to deal with unpleasant (and
apparently unintended, according to this story) consequences, such as
causality violation and time travel.
Instead, just ask this: Instant communication according to whom?
Schattke is once again asserting absolute simultaneity, which special
relativity explicitly dissolves. So we're back to his core confusion
about relativity.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Gods are born and die, but the atom endures.
-- Alexander Chase
Dorothy J Heydt
Paul Colquhoun
| Dorothy J Heydt wrote:
|> In article <kiai26dn8p72hlhpl...@4ax.com>,
|> Howard Brazee <how...@brazee.net> wrote:
|>> Heinlein's Time For The Stars doesn't fit Special Relativity. I
|>> don't remember how much acceleration was in most of the trip - anybody
|>> remember?
|>>
|>> At any rate - how do we fix Time For The Stars, keeping the premise of
|>> instantaneous twin communication?
|>
|> Um ... how about fixing instantaneous twin communication first?
|>
|> Not to mention marriage WELL within the forbidden degrees of
|> consanguinity.
|
| She was his great grandniece I believe?
|
| First off, this means she is not a direct descendant (which disqualifies
| a couple for marriage in California regardless of the number of
| generations).
Overlooking the fact that the original brothers were identical twins, so
he was genetically identical to her ancestor.
| Looking at the matter genetically, psychic-space-guy has a 1/2 chance of
| inheriting a lethal recessive from one of his parents, while
| psychic-Earth-GGNiece has a 1/16 chance. Their children have a 1/4
| chance of getting said gene from Dad and a 1/32 chance from Mom, so they
| have a 1/128 chance overall.
Shouldn't you be adding these chances instead of multiplying? Giving
9/32, only slightly worse than the 8/32 (= 1/4) chance from him alone.
| This is a degree of genetic risk roughly midway between second and third
| cousin marriage. Second cousin marriage is allowed everywhere in the
| world, and third cousins actually have a better-than-normal fertility
| rate. (Even first cousin marriage being widely outlawed is unique to the
| U.S., it is allowed most everywhere else and is common in some cultures.)
|
| So - Heinlein did his homework here too.
--
Reverend Paul Colquhoun, ULC. http://andor.dropbear.id.au/~paulcol
Asking for technical help in newsgroups? Read this first:
http://catb.org/~esr/faqs/smart-questions.html#intro
Carey
> On Mon, 28 Jun 2010 22:16:11 -0700, Carey <care...@gmail.com> wrote:
> | Dorothy J Heydt wrote:
> |> In article <kiai26dn8p72hlhpl...@4ax.com>,
> |> Howard Brazee <how...@brazee.net> wrote:
> |>> Heinlein's Time For The Stars doesn't fit Special Relativity. I
> |>> don't remember how much acceleration was in most of the trip - anybody
> |>> remember?
> |>>
> |>> At any rate - how do we fix Time For The Stars, keeping the premise of
> |>> instantaneous twin communication?
> |>
> |> Um ... how about fixing instantaneous twin communication first?
> |>
> |> Not to mention marriage WELL within the forbidden degrees of
> |> consanguinity.
> |
> | She was his great grandniece I believe?
> |
> | First off, this means she is not a direct descendant (which disqualifies
> | a couple for marriage in California regardless of the number of
> | generations).
>
>
> Overlooking the fact that the original brothers were identical twins, so
> he was genetically identical to her ancestor.
Oh, right - yes I was (silly of me). Makes a big difference.
>
>
> | Looking at the matter genetically, psychic-space-guy has a 1/2 chance of
> | inheriting a lethal recessive from one of his parents, while
> | psychic-Earth-GGNiece has a 1/16 chance. Their children have a 1/4
> | chance of getting said gene from Dad and a 1/32 chance from Mom, so they
> | have a 1/128 chance overall.
>
>
> Shouldn't you be adding these chances instead of multiplying? Giving
> 9/32, only slightly worse than the 8/32 (= 1/4) chance from him alone.
No, I shouldn't - but I should have explained it correctly. I was
calculating the chances of getting two copies of the lethal recessive,
not one (the only case that causes bad results).
The additive calculation would be for a dominant lethal/disease gene
(like the famous hemophilia gene
But doing it with the identical twin fact gives a 1/32 chance overall.
> | This is a degree of genetic risk roughly midway between second and third
> | cousin marriage. Second cousin marriage is allowed everywhere in the
> | world, and third cousins actually have a better-than-normal fertility
> | rate. (Even first cousin marriage being widely outlawed is unique to the
> | U.S., it is allowed most everywhere else and is common in some cultures.)
And let me point out that I also miscounted generations (to make for a
thoroughly bollixed post - don't try doing this stuff in your head at 11
pm just before you retire for the night). The relationship degree I
calculated (incorrectly - forgetting the identical twin relationship)
was between that of first and second cousins.
Taken together these corrections yield a consanguinity that is somewhat
closer than first cousins. It is genetically the same as regular
uncle-niece marriage.
This is certainly alarming territory for cousin-marriage-squeamish
Americans, but this degree of relatedness is still permitted in much of
the world. Australia for example permits uncle-niece marriage, and as do
cultures where first cousin marriage is common (not just legal). And
since the formal (not genetic relationship) is more remote that
uncle-niece it probably escapes prohibition in most places where
uncle-niece marriage is not allowed.
And in terms of actual genetic hazard - an uncle-niece relationship
gives an increased chance of disease around 1.7-2.8% over background
(that is a small incremental increase, not some gross multiple of
background rates which Americans seem to assume is the case for 2nd and
3rd degree marriage).
The exaggerated American abhorrence of consanguineous marriage seems to
have arisen due to incorrect 19th century "research" claims about "bad
blood" (at this same time false claims about hereditary criminality were
being made). And it seems to be preserved in part by hick-mockery,
backwoods folk did not get the (wrong) word about cousin-marriage in the
19th century and so preserved historical marriage patterns. (In a
similar vein hill billies get derisive treatment for preserving
Elizabethan speech patterns.)
James Nicoll
>Jonathan Schattke <wiz...@gmail.com> wrote:
>>On 6/28/2010 6:06 PM, Howard Brazee wrote:
>>> Heinlein's Time For The Stars doesn't fit Special Relativity. I
>>> don't remember how much acceleration was in most of the trip - anybody
>>> remember?
>>
>>If I recall correctly, the acceleration was 1G for most of the trip. I
>>think R.A.H. did the calcs for that, assuming some magical reaction drive.
>
>On huge sheets of butcher paper spread all over the kitchen
>table? Possibly.
I think that was one of the interplanetary stories.
The trip times in TFTS tend to be too short for the given accelerations
and distances.
--
http://www.livejournal.com/users/james_nicoll
http://www.cafepress.com/jdnicoll (For all your "The problem with
defending the English language [...]" T-shirt, cup and tote-bag needs)
James Nicoll
Greg Goss <go...@gossg.org> wrote:
>Howard Brazee <how...@brazee.net> wrote:
>
>>Heinlein's Time For The Stars doesn't fit Special Relativity. I
>>don't remember how much acceleration was in most of the trip - anybody
>>remember?
>
>Did they use 1 G accelleration all the time, or did they blast up to
>relativistic speed then spin the ship?
One G+ all the time. If they'd coasted the trip times would have been
even more incorrect than they were.
There's a pattern with the Heinlein juveniles that the later they are,
the softer the science is:
1. Rocket Ship Galileo, 1947
2. Space Cadet, 1948
3. Red Planet, 1949
4. Farmer in the Sky, 1950
5. Between Planets, 1951
6. The Rolling Stones aka Space Family Stone, 1952
7. Starman Jones, 1953
8. The Star Beast, 1954
9. Tunnel in the Sky, 1955
10. Time for the Stars, 1956
11. Citizen of the Galaxy, 1957
12. Have Space Suit.Will Travel, 1958
In fact, there's a really nice divide between #6 and #7, where you
go from Hohmann orbits and trip times of years to get around
the inner system and out to the asteroid belt to ships that accelerate
forever, right up to the speed of light (which seems to be treated as
a sort of escape velocity for the universe).
Later in when the tools to calculate these thigns were more available,
the less likely RAH was to have a setting that required more than a
quick S = 1/2at^2.
Wayne Throop
: 4. Farmer in the Sky, 1950
: 5. Between Planets, 1951
: 6. The Rolling Stones aka Space Family Stone, 1952
: 7. Starman Jones, 1953
: 8. The Star Beast, 1954
: from Hohmann orbits and trip times of years to get around the inner
: system and out to the asteroid belt to ships that accelerate forever,
: right up to the speed of light (which seems to be treated as a sort of
: escape velocity for the universe).
The divide isn't all *that* nice, since the fancy magic reactionless
drive used in 7 was invented in 5 (iirc... they were "Conrad-Horst
impellers", right?).
James Nicoll
And Ortega's Torch shows up in FARMER, although they don't use it to
its full potential.
Howard Brazee
>And in terms of actual genetic hazard - an uncle-niece relationship
>gives an increased chance of disease around 1.7-2.8% over background
>(that is a small incremental increase, not some gross multiple of
>background rates which Americans seem to assume is the case for 2nd and
>3rd degree marriage).
>
>The exaggerated American abhorrence of consanguineous marriage seems to
>have arisen due to incorrect 19th century "research" claims about "bad
>blood" (at this same time false claims about hereditary criminality were
>being made). And it seems to be preserved in part by hick-mockery,
>backwoods folk did not get the (wrong) word about cousin-marriage in the
>19th century and so preserved historical marriage patterns. (In a
>similar vein hill billies get derisive treatment for preserving
>Elizabethan speech patterns.)
I doubt if that research is the reason. But there are plenty of
societies with much more tight definitions of incest. Easter Island
is one, and it makes sense, with such a small, highly isolated
population.
There are societal advantages in marrying outside of one's closest
culture as well as genetic.
--
"In no part of the constitution is more wisdom to be found,
than in the clause which confides the question of war or peace
to the legislature, and not to the executive department."
- James Madison
care...@gmail.com
> On Tue, 29 Jun 2010 06:26:46 -0700, Carey <carey...@gmail.com> wrote:
> >And in terms of actual genetic hazard - an uncle-niece relationship
> >gives an increased chance of disease around 1.7-2.8% over background
> >(that is a small incremental increase, not some gross multiple of
> >background rates which Americans seem to assume is the case for 2nd and
> >3rd degree marriage).
>
> >The exaggerated American abhorrence of consanguineous marriage seems to
> >have arisen due to incorrect 19th century "research" claims about "bad
> >blood" (at this same time false claims about hereditary criminality were
> >being made). And it seems to be preserved in part by hick-mockery,
> >backwoods folk did not get the (wrong) word about cousin-marriage in the
> >19th century and so preserved historical marriage patterns. (In a
> >similar vein hill billies get derisive treatment for preserving
> >Elizabethan speech patterns.)
>
> I doubt if that research is the reason.
Have you a better explanation how these laws and attitudes came into
being then?
They aren't a reflection of the British Isles predecessor cultures
(which allowed cousin marriage), or contemporary Victorian society
(which allowed the same), and the "bad blood" pseudo-science hysteria
of the 19th century is well established, and had a large role in
giving rise to the eugenics follies in the early 20th century. And
current U.S. law (not in all states) against cousin marriage is a
definite outlier in world marriage patterns and laws.
I will accept a better explanation if someone has one.
Derek Lyons
>On Tue, 29 Jun 2010 06:26:46 -0700, Carey <care...@gmail.com> wrote:
>
>>The exaggerated American abhorrence of consanguineous marriage seems to
>>have arisen due to incorrect 19th century "research" claims about "bad
>>blood" (at this same time false claims about hereditary criminality were
>>being made). And it seems to be preserved in part by hick-mockery,
>>backwoods folk did not get the (wrong) word about cousin-marriage in the
>>19th century and so preserved historical marriage patterns. (In a
>>similar vein hill billies get derisive treatment for preserving
>>Elizabethan speech patterns.)
>
>I doubt if that research is the reason. But there are plenty of
>societies with much more tight definitions of incest. Easter Island
>is one, and it makes sense, with such a small, highly isolated
>population.
Which doesn't explain why a large and non isolated population like the
hill folks of the Applachian represents an island in the larger
society around them.
Howard Brazee
>> I doubt if that research is the reason.
>
>Have you a better explanation how these laws and attitudes came into
>being then?
>
>They aren't a reflection of the British Isles predecessor cultures
>(which allowed cousin marriage), or contemporary Victorian society
>(which allowed the same), and the "bad blood" pseudo-science hysteria
>of the 19th century is well established, and had a large role in
>giving rise to the eugenics follies in the early 20th century. And
>current U.S. law (not in all states) against cousin marriage is a
>definite outlier in world marriage patterns and laws.
>
>I will accept a better explanation if someone has one.
I don't think society generally uses scientific papers to define its
mores. That isn't what happened in Easter Island and other places
with strong incest taboos. The U.S. was built up with colonies.
Different immigrant groups moved into insular communities where they
can support each other. When this happens, there is a
counter-pressure to make sure they aren't *too* insular.
Dan Goodman
> I don't think society generally uses scientific papers to define its
> mores.
However, it's been known to use bad science to define its mores. And
this definitely happened with eugenics; forced sterilizations, for
example.
--
Dan Goodman
"I have always depended on the kindness of stranglers."
Tennessee Williams, A Streetcar Named Expire
Journal dsgood.dreamwidth.org (livejournal.com, insanejournal.com)
Dorothy J Heydt
Howard Brazee <how...@brazee.net> wrote:
>On Tue, 29 Jun 2010 06:26:46 -0700, Carey <care...@gmail.com> wrote:
>
>>And in terms of actual genetic hazard - an uncle-niece relationship
>>gives an increased chance of disease around 1.7-2.8% over background
>>(that is a small incremental increase, not some gross multiple of
>>background rates which Americans seem to assume is the case for 2nd and
>>3rd degree marriage).
>>
>>The exaggerated American abhorrence of consanguineous marriage seems to
>>have arisen due to incorrect 19th century "research" claims about "bad
>>blood" (at this same time false claims about hereditary criminality were
>>being made). And it seems to be preserved in part by hick-mockery,
>>backwoods folk did not get the (wrong) word about cousin-marriage in the
>>19th century and so preserved historical marriage patterns. (In a
>>similar vein hill billies get derisive treatment for preserving
>>Elizabethan speech patterns.)
>
>I doubt if that research is the reason. But there are plenty of
>societies with much more tight definitions of incest. Easter Island
>is one, and it makes sense, with such a small, highly isolated
>population.
>
>There are societal advantages in marrying outside of one's closest
>culture as well as genetic.
Well, when I brought up the seven forbidden degrees of
consanguinity I was not referring either to good genetic theory
nor to American law. It was a concept from the Middle Ages, in
which between the prospective bride and bridegroom there must be
at least seven ancestors not in common. This means that they can
have no common relative closer than a great-great-grandparent.
E.g.,
Common ancestor
_____________|_____________
| |
Great-great-grandparent Great-grandparent
| |
Great-grandparent Grandparent
| |
Grandparent Parent
| |
Parent Bridegroom
|
Bride
Here you can count eight separate ancestors linking the bride and
the bridegroom, which would put them outside the seven forbidden
degrees.
Mind you, in the case of the nobility, who were ferociously
inbred because they'd all been marrying each other since the
memory of man runneth not to the contrary, it got exceedingly
difficult to find someone you could marry who was outside the
seven forbidden degrees, and there were a lot of applications to
Rome for a dispensation (which was usually granted, since the
Pope could generally recognize the validity of "but there isn't
ANYBODY of my class in Europe who ISN'T my cousin!").
Derek Lyons
>On Tue, 29 Jun 2010 12:09:24 -0700 (PDT), "care...@gmail.com"
><care...@gmail.com> wrote:
>
>>> I doubt if that research is the reason.
>>
>>Have you a better explanation how these laws and attitudes came into
>>being then?
>>
>>They aren't a reflection of the British Isles predecessor cultures
>>(which allowed cousin marriage), or contemporary Victorian society
>>(which allowed the same), and the "bad blood" pseudo-science hysteria
>>of the 19th century is well established, and had a large role in
>>giving rise to the eugenics follies in the early 20th century. And
>>current U.S. law (not in all states) against cousin marriage is a
>>definite outlier in world marriage patterns and laws.
>>
>>I will accept a better explanation if someone has one.
>
>I don't think society generally uses scientific papers to define its
>mores.
No? Explain then the change in societies attitude towards smoking and
weight in the last forty years.
But Carey wasn't talking about scientific papers - he was talking
about pseudo scientific hysteria, which (like can scientific papers)
can and do shape both more and law.
>The U.S. was built up with colonies. Different immigrant groups moved into
>insular communities where they can support each other.
Except for the niggling problem that this doesn't actually describe
the historical United States, or account for the fact that in the
historical United States outmarriage was in fact frowned upon by the
groups that were insular.
care...@gmail.com
> In article <gjdk26lvp429up0brfbm2esrjdug7gq...@4ax.com>,
Ah, you are referring to Canon Law.
Here is an interesting link that explains this and provides some
useful observations that put this in context:
http://www.rootsweb.ancestry.com/~medieval/consang.htm
It would appear that the introduction of a strict 7th degree
separation rule AND a stricter counting procedure was of questionable
practical significance because:
1. Nobility, which maintained the genealogical records required to
enforce it, ignored this rule at there convenience;
2. Common folk did not have the records required to enforce it, nor
the attention of the upper clergy who might have cared to.
I think culture practice was not much influenced by this church law.
It is interesting that Roman Law banned first cousin marriage, but
permitted any greater separation (again, this only applied in practice
to the Better Classes, I suspect - peasantry were probably not
troubled by this prohibition).
The unworkable 7th degree separation rule reminds me also of the
Biblical curse on mamzerim (bastards) which in Deuteronomy 23:2 it is
said: "No one born of a forbidden marriage nor any of his descendants
may enter the assembly of the Lord, even down to the tenth
generation."
This 10th generation restriction was utterly impossible to apply in
practice since in a typical population group everyone is descended
from everyone else after 10 generations, and the necessary records are
generally non-existent.