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Date:      Sat, 3 Feb 2001 12:03:57 +0100
From:      Rahul Siddharthan <rsidd@physics.iisc.ernet.in>
To:        Terry Lambert <tlambert@primenet.com>
Cc:        j mckitrick <jcm@FreeBSD-uk.eu.org>, freebsd-chat@FreeBSD.ORG
Subject:   Re: quote about open source
Message-ID:  <20010203120357.B94275@lpt.ens.fr>
In-Reply-To: <200102022305.QAA16383@usr08.primenet.com>; from tlambert@primenet.com on Fri, Feb 02, 2001 at 11:05:58PM %2B0000
References:  <20010202151744.O38235@lpt.ens.fr> <200102022305.QAA16383@usr08.primenet.com>

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Terry Lambert said on Feb  2, 2001 at 23:05:58:
> > By that reasoning, there can't be innovation in science either,
> > because it's always been "open source" -- share your ideas, publish
> > them, etc.  The idea of patenting scientific discoveries is pretty
> > recent, and even so, the equivalent of "closed source" (hide your
> > methods, reveal only your results) just doesn't exist -- because
> > people know such things cannot be taken seriously.  
> 
> You are aware that both Feynman and Dyson used Clifford Algebras
> to do much of their ground breaking work, but did not share this
> tool with their collegues, right?  Most of the early QED (Quantum
> Electro Dynamics) work they did appeared to "skip steps" for most
> of their contemporaries, who lacked these tools.  There was a lot
> of "the proof is left to the student", which seemed like hand
> waving.  Even today, unless you take your QED classes from an
> extremely enlightened professor, you are likely to not ever hear
> about Clifford algebras, and even get a theoretical physics
> degree, without laying your hands on this important tool.
 
Well, I haven't read the early QED papers and don't know very much
about the subject anyway (I'm not in high energy physics); I'll come
back to the subject of Feynman below.  But yes, what goes into the
paper isn't necessarily how you yourself arrived at the results.
However, the paper should make at least enough sense for the referee
to believe the answers...

It's pretty common even in "open source" for someone to work on
something alone, without telling anyone, and then spring it on to the
world when it's in a working state.  The linux kernel is itself an
example.  My point was, you know a scientific claim works when you
know all the steps of the theoretical reasoning or the experiment; you
know a program works correctly (and no back doors, etc) when you have
the source code in front of you.  You are pointing out that there may
be several ways to arrive at a scientific result, and scientists may
keep some method to themselves.  That is true, but they still publish
*some* method to satisfy the rest of the world.  I'm not sure there's
an analogue for this in programming: if you want to verify that a
program works as it should, you'll want the source to *that* program,
not the source to some other program which gives you identical
results.  

The correctness of computer programs can actually be a problem in
physics too, given the reliance on computer simulations these days.
Most people don't publish the source code to their simulation
programs: the only way to verify the correctness of a simulation is
for someone else to write their own code for the same problem, and
compare the results.

Coming back to Feynman -- his major contribution to physics was surely
the idea of path integrals, which led to a diagrammatic way of doing
perturbation theory, called "Feynman diagrams".  Many of his results
in QED were derived by Schwinger and others algebraically, but Feynman
could do them much faster and much more intuitively.  But the whole
reason for accepting his methods was that he published them, and
explained them, and they made sense to everyone.  Compare a
mathematician of the early 20th century: Srinivasa Ramanujan.  He 
was not trained in the Western way, and had a habit of doing his
calculations on a slate, rubbing them out, and only writing his
results in a notebook; and people are still trying to prove those
results today.  His notebook was sufficiently interesting for people
to make the effort to prove it all, but nothing he says can be trusted
without proof.  In a few cases he's been shown wrong, in fact.
Now, the proofs that have been published may not be what he had in
mind (and he may not have had a rigorous proof in mind at all), but
any proof, if rigorous, will do.  Most conventional
mathematicians/scientists justify everything they say properly in
their papers, but the arguments they actually write may not be the
ones they originally used to arrive at their results.

> I am aware of a number of physicists who are working on what
> I consider absolutely brilliant ideas, and who have made very
> significant progress in predicting phenomena, going down their
> roads less travelled, but who are completely unwilling to share
> their work, except in a very small circle of trust, until they
> have pushed it much farther.  One of these physicists literally
> predicted the existance of the W particle _from theory_, and,
> further, calculated its energy _on the nose_, back in the
> early 1970's, and _still_ has only published bits and pieces.
> 
> 
> As a more contemporary example, the Taniyama-Shimura conjecture
> (that all elliptic curves have modular forms), which if proven,
> proved Fermat's last theorem, was worked on by the mathematician
> involved in total silence and isolation, until he believed he
> had solved the problem.
> 
> 
> Perhaps my favorite example is when Sir Edmund Halley went to
> Newton, described his concept of a "comet", and asked Newton
> to help him figure out what shape the orbit would take.  Rather
> than embarking on a long project over many years, Newton thought
> about it for a few minutes, seemingly considering whether to
> undertake a project that would cost him a large chunk of his
> adult life, and stated "an ellipse".  Newton, of course, did
> not bother to tell Halley that he had earlier invented calculus.

Newton did, of course, eventually publish his results.  I'm not really
familiar with the other stories.  My point is, in science you nearly
always have to publish compelling arguments to support any claim you
make; and the more surprising the claim, the more thorough the
arguments required.  Your point about "trade secrets" which are not
actually revealed in published work is correct, but as far as I am
aware, in today's world at least, the published work should contain
some alternative argument.  Another reason to hide such "trade
secrets" is that the people concerned may not be convinced about their
correctness -- they are tricks that work, but their answers must be
verified in other ways.  Newton, for example, took many years to prove
that two spheres attract each other in the same way as two point
masses located at their centres; until he had a satisfactory proof, he
did not want to publish it, but this was quite crucial to calculating
planetary orbits and so on.  Feynman had problems convincing older
physicists of the correctness of the diagram approach (How can you
draw a line representing an electron?  What about the uncertainty
principle?...)  

The works of people like L D Landau and P W Anderson (probably the
people most responsible for whatever we know about "condensed matter"
today) are generally brilliantly argued and very persuasive, but you
get the feeling that they somehow "knew" all these things intuitively,
and the arguments came only later.  Maybe such people have "trade
secrets" of their own.

None of these situations seem to arise in programming.  But the
fundamental requirement, that in order to be satisfied about the
correctness you have to see the inner working, is still there.  And
it is quite possible for someone to work alone, and "publish" the
program only when sure of its correctness.

- Rahul


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