RE: Development: A Structured Problem Area?

Quoting Andrew Hunt <andy-CFUc0I3L9bbJyQSMb4qrZi4gXjV2jqTv@xxxxxxxxxxxxxxxx>:

> As soon as you get a number of independent agents interacting, you can
> get emergence.  It can happen in social situations, obviously (a team is
> a collection of independent agents interacting).  But it can also
> happen--by accident or design--in software systems.  Programs like the
> Game of Life do it by design.  Programs with highly-coupled, interacting
> pieces may begin to show emergence by accident (and not on the happy
> end).  
> 
> Have you ever witnessed a system that started acting "bizarrely"? That
> is, started exhibiting inexplicable bugs that turned out to be caused by
> the unforseeen interaction of multiple components?  That's not just a
> bug, it's an emergent bug.  At least I would certainly classify it as
> such.

I am quite intrigued by these ideas but I'm not yet persuaded, perhaps because I
haven't fully grasped them.

To restate, we're talking about accidental emergence in meant-to-be-non-complex
software.

(1) Is it emergence if an easy-to-predict interaction was simply not seen? Or is
emergence something different, where the order resulting from interaction was
not only unforeseen but unforeseeable?

(2) Is it possible to write software in a way such that it will not show
emergence? Or is emergence unavoidable? 

(3) Why is it possible to write an optimizing Java compiler that doesn't suffer
from emergence but not higher-level systems (assuming the answer to #2 is
"unavoidable")?

Derek Richardson


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