
Cornell Chronicle: Computer derives natural laws - muon
http://www.news.cornell.edu/stories/April09/NaturalLaws.ws.html
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Rod
_"Their process begins by taking the derivatives of every variable observed
with respect to every other -- a mathematical way of measuring how one
quantity changes as another changes._ "

In an ideal world, that could be done. But am I the only one who is wondering
where noise comes in? All measurements are noisy, and computing derivatives
from noisy data sounds sketchy.

 _"Then the computer creates equations at random using various constants and
variables from the data. It tests these against the known derivatives, keeps
the equations that come closest to predicting correctly, modifies them at
random and tests again, repeating until it literally evolves a set of
equations that accurately describe the behavior of the real system.
Technically, the computer does not output equations, but finds "invariants" --
mathematical expressions that remain true all the time, from which human
insights can derive equations."_

Once again, if the data is noisy, then the program can't find true invariants.
Perhaps it can "guess" them. I would like to see that source code and the data
sets these guys have used.

