David Peterson wrote:

What's your definition of an entity? Seems there are programs (or
could be) capable of creating equal, and perhaps better programs.

A compiler, for example...

More useful examples are things like learning systems; there are systems
that develop a program expressed as a series of rules. It runs tests
against past data in which each rule is assessed for how much it helped,
and bad rules removed, and good rules duplicated and variations tried.
Solutions evolve automatically.

A spectacular case in point... some group decided to use an FPGA
(programmable digital logic chip; you feed in setup instructions to tell
it what gates to wire to what, more or less), along with an evolving
engine like that above, to evolve a circuit to work out the frequency of
a train of pulses. The FPGA was too small (not enough gates) to contain
the circuit you'd get if you designed it by hand.

Sure enough, it soon came up with a working design... but the way it had
managed to do better than what was thought to be the theoretical
capacity of the chip was that it wasn't using them just as digital logic
gates any more. It had gates wired back into themselves in unstable
feedback loops, using their analogue characteristics (which you steer
clear of in digital design!). Which was fine - but as soon as the
temperature changed, the chip's analogue characteristics shifted and the
circuit stopped working :-) They'd trained it in a stable temperature
environment, so it had evolved to need that...


Dave


ABS