[Cross-posting to soc.history.science, because it has stuff about history
of science. If that group were alive, it could contribute useful criticism
to this discussion.]
On Sun, 10 Feb 2008 05:53:44 UTC, "Society" <Society@[EMAIL PROTECTED]
>
wrote:
>
> "PolishKnight" <marek1@[EMAIL PROTECTED]
> wrote in message
> news:marek1-6448F6.19502409022008@[EMAIL PROTECTED]
> >...
>
> >> > I'm reminded of Galileo's conclusion about a heliocentric
> >> > solar system versus a geocentric one. It turns out that
> >> > he was right
>
> Bzzzt!!! Wrong. Galileo was wrong. Like Copernicus, who
> a generation before Galileo had proposed a heliocentric
> solar system, Galileo's system assumed that the planets
> followed a circular path around the sun. Any astronomer
> with the mathematical tools and observational data of the
> day could -- and did! -- demonstrate that Galileo, like his
> predecessor Copernicus, was wrong.
This is complete and unadultered bosh. Its bogosity is a little bit
complex, though, so a bit of explanation is in order.
>
> >> > but had errors in his scientific proof
>
> Bzzzt!!! Wrong, wrong, wrong. Galileo's errors were
> not mere boo-boos in some complicated calculations.
> One of his basic assumptions, that planets followed
> circular paths (an assumption, btw, that he shared with
> Ptolemy), was just plain wrong. Also, Galileo made
> other mistakes in his arguments for heliocentrism.
First, let's just analyze it a little. First, it's claimed that the
approach of Copernicus and Galileo was obviously wrong. Then it turns out
that Ptolemy was wrong in the same way.
What a great reason for rejecting Galileo in favor of Ptolemy!
Or is the idea that everyone should have stuck to Aristotle? Oops:
circles! Or Plato? Oops again.
And of course, Ptolemy's system was actually good, for the time, at
predicting the observed motions of the planets. He developed it because
the older ideas, like Aristotle's, were impossibly far off.
Now to business.
The tiny core of fact in those claims that it was indeed possible to
observe errors in a really simple set of circular orbits. In fact, it was
possible in antiquity; and it was done; and in the first century AD
Ptolemy came up with a system that corrected for those problems.
We now attribute those problems to the fact that the orbits are not
circular. Ptolemy worked around them with epicycles and things.
You've heard of epicycles. There are the famous big ones that were used to
account for the fantastically irregular way in which planets reverse
course in what Kepler called a "pretzel" across the sky. Copernicus got
rid of those by showing it was simply an effect of parallax.
But apart from that, there are a lot of speedings and slowings and
deviations left over. Ptolemy handled those with eccentrics, equants, and
more epicycles. There's a story going around the Copernicus had more
epicycles than Ptolemy! And it's true: he decided to eliminate the
equants, replacing them with epicycles. Same effect.
And the effect, for Ptolemy *and* for Copernicus, was that the oddities
caused by elliptical orbits got accounted for. It's all in Copernicus. It
is absolutely ridiculous to say that his system was wrong (observationally
wrong) because of not accounting for these irregularities, because it did
account for them, in much the same way as Ptolemy did.
So why didn't Galileo talk about these things? Perhaps because he was not
writing a treatise on astronomy and how to predict planet's movements; he
was writing a comparison of two methods of accounting for the heavens.
There's a very subtle effect here, which I'll try to state tersely:
When two systems encounter the same problem and handle it in the same way,
that does not constitute a difference between the systems.
This may account for Galileo's not writing about it among the differences.
He described the systems as boiled down to the differences, rather than
cluttering his little book (450 pages, in English) with irrelevancies.
If anyone suspects I'm quibbling, here's a simple way of answering me:
Find the people who said *at the time* that Galileo and Copernicus were
wrong because they didn't handle these perturbations of the all-circular
system. Better yet, because more relevant: find where the Church said
that.
We're waiting for the citations.
Meanwhile in this universe, that's not what happened. Everyone who was
involved in astronomy knew about the complexities in Ptolemy's system, and
everyone who looked at Copernicus knew about the same in his system; and
Galileo was writing about the *differences*.
>
> >> > and was rejected by the academic consensus of
> >> > the day.
>
> Darn those Jesuit astronomers, undermining a guy like
> Galileo. ;-)
Actually, the Jesuit astronomers, as a whole, didn't cause him much
trouble about the system. After being highly skeptical about the matters
in the Starry Messenger (1610), they managed to get good enough
telescopes, and changed their minds like good scientists (or
philosophers). They weren't fighting with him in 1616, and after that they
mostly avoided the subject as being dangerous. Some people believe that
they were secretly behind the persecution in 1633, because of his feud
with the Jesuit Scheiner; others don't.
>
> >> > No nobel prize for him! :-) (Of course, there were no nobel
> >> > prizes in those days if you feel urged to point that out.) :-)
> >>
> >> I guess that example shows that people who don't get the details
> >> right are not likely to convince others to believe in them.
> >
> > Yeah, that's why we all believe that the sun revolves around
> > the Earth today! :-)
> >
> > Galileo made a typo and reasoned minds were able to see past it.
>
> Bzzzt!!!
>
> Galileo's errors were no mere "typo". Those "reasoned minds"
> were _not_ able to "see past it" precisely because Galileo's
> errors included some that were fundamental mistakes about
> the nature of heavenly bodies. Tycho Brahe spent a lifetime
> trying to collect better observational data and he too took for
> granted the idea of circular paths. He tried to patch up the
> well-known flaws in the Copernican system with his
> geo-heliocentric model, in which the other planets orbited
> the sun which itself circled the earth.
No. The "well-known flaws" were two: the lack of stellar parallax, and the
fact that the Earth was considered to be moving. The latter isn't really a
flaw, except as a matter of circular argument. The former was never a good
argument, because anyone who knew his Euclid could see that it was a
matter of the size of the Universe. (Speaking of knowing your Euclid:
Archimedes knew this, and he hadn't studied Euclid at a university.) So,
logically, the problem was that Copernicus required the universe to be
bigger than some people wanted it to be.
>
>
<http://en.wikipedia.org/w/index.php?title=Tycho_Brahe&oldid=189765046#Tycho.27s_Geo-heliocentrism>
>
> Johannes Kepler, using Tycho Brahe's observational data,
> was able to show that the paths of the planets -- including
> Earth -- fit well with the assumption that they went around
> the sun in _elliptical_ paths. Abandoning the assumption
> that heavenly bodies moved in circles, as Kepler did, was
> IMO an intellectual leap comparable to Einstein's rejection
> of earlier views that space and time are absolutes and
> independent of the motion of a body. Some scientists,
> including the aging Galileo, did not accept Kepler's ideas
> about planets following elliptical paths.
Kepler's work on elliptical orbits was one of the most brilliant pieces of
science ever done, and not least because of its rejection of what everyone
had always known.
By the way, if you want a laugh, think about how much better Galileo's
book would have been received by those Church authorities who supposedly
hated his bad science, if he had done it better by using Kepler's work:
"Oh, I see it now! The planets don't move in perfect circles the way
Aristotle, the Master of Those Who Know, said. No, the perfect Heavens are
built on bulging ellipses, inelegant and very hard to compute with. Now it
makes sense, and we must admit that Galileo's doing good philosophy. And
get this -- the joke's on us -- we've been misinterpreting Scripture all
this time! A-ha-ha-ha-ha!" [Sounding like the laughing bishop in Brecht's
play]
No, I don't think so. Improving the science would have helped about as
much as citing Saint Augustine. (We're getting to that.)
>
> > What this example proves is that people who don't get the
> > details right, and only use details, are not likely to convince
> > others to discard their faith and strong prejudices. But then
> > again, even if Galileo had gotten all his details right that's
> > no guarantee the Vatican would have changed its mind
> > right away.
>
> I doubt that -- remember, Galileo had been enjoined not
> to teach speculations as fact and _that_ is what he had done
> in his _Dialogue on the Two Chief World Systems_.
> (Mocking the Pope in that book didn't help Galileo's cause
> either. One could say that Galileo wasn't a people person,
> a charge often levied against academics -- especially
> scientists, and most especially against physicists.)
A very complex case, reduced here to some popular stories. The mocking of
the Pope consists of his publi****ng a notion that the Pope ordered him to
publish, and putting it in the mouth of the wrong person. A large
mythology has been built around that.
>
> Had Galileo been able to prove his claims correct, he
> would have had sup****t in the theological writings of
> among others, Saint Augustine,
-- whom Galileo quoted extensively, but it didn't do him any good, just
getting him in more trouble, until the 1990s when Pope John Paul admitted
that the Church authorities had been wrong about this --
who had argued against
> what today we know as fundamentalist Protestant bible
> literalism. St. Augustine taught that if an interpretation
> of the words of the Holy Bible appear to contradict
> other known truths, then it is that _interpretation_ of the
> bible -- not the bible itself or those other truths -- that
> is in error.
Which was the point Galileo made extensively, and with citation of
Augustine, and much good it did him.
So, the Church would not have had as much
> trouble accomodating its teachings to new scientific
> discoveries as today's critics of the Church suppose.
It *did* have a great deal of trouble. Would you like to cite some part of
the Inquisition's findings that criticizes his science? Would like to see
a part that says that "the doctrine of the earth's motion and sun's
stability is contrary to Holy Scripture and so can be neither
defended nor held"? Congratulations, you've just seen it, from the
do***ent that found him quilty of vehement suspicion of heresy. Want
another, to the same effect? Supplied upon request.
> You'll notice that it's not the Church but Protestants
> and atheists who have had trouble reconciling the
> theories of biological evolution and the big bang
> theory* with their dogmas.
Dogma, schmogma. (Referring, of course, to atheists and other scientists
who have had trouble with Big Bang; the Fundies can take care of
themselves, and if fact are too successful at it.) There are serious
philosophical problems with Big Bangs and giant singularities; sadly,
there are equally serious ones with the infinitely old Steady State, which
violates conservation laws. But I don't what, if anything after the 1970s,
is being referred to as atheists' dogmatic problems with BB.
>...
--
Dan Drake
dd@[EMAIL PROTECTED]
|
