
Doing the Impossible - lambdatronics
https://heteroskedasticblog.wordpress.com/2020/07/12/doing-the-impossible/
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MrLeap
This is a great article. I'm going to pass it on to a friend of mine. This
particular friend's life's ambition has been to build a perpetual motion /
free energy device.

Now, I imagine people's immediate reaction is to sneer and grab for their
nearest thermodynamics pamphlet. That was my initial inclination. Watching how
_industrious_ and _persistant_ this guy has been trying over the years
softened me. He's probably built 20+ prototypes. None of which have worked,
but he keeps trying.

Science is about reproducibility, and as far as I'm concerned, he's performing
guerrilla research of the kind for which there is no funding.

His primary motivation is providing energy to himself and his parents. He's
abjectly poor, and grew up that way. His circumstances have him mostly
trapped. Child support delinquency had his drivers license taken. Where he
lives was given to him, and he's an hour away from the nearest city.

He's my crystalized example of infinite intelligence, limited information,
meager childhood. I spent a few weeks teaching him python, and he got through
all the exercises in learn-python-the-hard-way faster than I did. He refuses
to believe anyone would hire a 50 year old man with no resume to do it
remotely, so he hasn't tried. He might not be wrong.

Thinking through it myself, it's hard to imagine we've _exhausted_ all lanes
of creativity generating and storing electricity. That one company that uses a
tower of concrete blocks and a crane to store energy comes to mind as a
clever, simple in hindsight ingenuity.

This article seems like a good way to get him to take a gander at
impossibility proofs/arguments from a perspective compatible with his "NOBODY
WILL STOP ME" levels of grit and persistence.

Frankly I want to coerce him into building a small personal steam engine. His
goal is 1000W, to supplement solar panels when it's cloudy. He currently has a
gas generator, but keeping it filled is onerous, even when the gas is free.

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lambdatronics
Thanks! That's an interesting story about your friend. I've met a few people
like that. It reminds me of PG's 'bus ticket theory of genius:' being
obsessive may be a necessary ingredient, because it helps with persistence.
[http://paulgraham.com/genius.html](http://paulgraham.com/genius.html)

~~~
MrLeap
Another great one! Thank you for the great reads :)

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btilly
My favorite example of an impossibility theorem being violated in practice is
rsync.

The theorem being that there is no perfectly reliable algorithm to compare two
files across a network and see if they are different that in the worst case
does not require at least as much bandwidth as transferring one file to the
other.

Lots of algorithms do better on most files we see. For example compress and
send a compressed file. But in the worst case, the compressed file can be
larger than the original and you have to transfer it.

Enter the rsync algorithm. It sends a _tiny_ amount of data. Just a hash. The
gotcha is that it has a very small chance of incorrectly concluding that two
files are the same. But the odds that it gets it wrong are in practice lower
than the odds of it getting it wrong because of a hardware failure during the
computation. (The algorithm continues doing more hashes to narrow down to just
the differences if the file needs to be updated.)

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lambdatronics
You make in interesting point. Much of algorithmic information theory seems to
be focused on the worst case, when the average behavior may be more relevant
-- and significantly more pleasant.

It brings to mind Zipf's law and optimal coding. There's a 'no-free-lunch'
theorem waiting to be discovered, I suspect -- or maybe it already exists and
I just haven't heard of it. Something along the lines that optimal encoding
maximizes the channel capacity, but makes the worst case error exponentially
disastrous.

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lambdatronics
Ahh, I just remembered another quote I should have mentioned: "To discover new
things, you have to work on ideas that are good but non-obvious; if an idea is
obviously good, other people are probably already working on it. One common
way for a good idea to be non-obvious is for it to be hidden in the shadow of
some mistaken assumption that people are very attached to."
[http://www.paulgraham.com/nov.html](http://www.paulgraham.com/nov.html)

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cjg
My favourite in this category is the impossibility of a halting oracle, which
relies on the assumption that there is infinite memory. An assumption which is
wrong in most practical cases.

There's a trivial implementation of a halting oracle when memory is a fixed
size - run until a state is revisited or the program exits.

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donclark
His four social media links at the top do not link to him - just the generic
websites.

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lambdatronics
Ahh, I will remove those default icons -- I don't have social media accounts.

