I've received some feedback on my initial post - which is nice. Ric Parkin advised caution about drawing analogies from The Quantum Self - mostly because any analogy, when stretched too far, will snap. And I agree. Analogies can be useful but you musn't forget that software is a discipline in its own right. So to expound a little, when I was thinking of the particle/wave analogy I wasn't thinking of the dynamic aspect, the interaction - I was likening the particle aspect to the inside of an entity and the wave aspect to its connections to the outside. The shape. The fractal shape if you like (since I'm also reading Chaos). Shape is important. Richard Gabriel talks about shape quite a lot in his excellent book Patterns of Software. Kevlin Henny (who incidentally, coined the phrase "less code more software") also had some insightful comments on the word follows in "form follows forces". It suggests moving only in one direction, and we all know this is not the case. Developing software is not a linear process. Feedback is natural and healthy. If there was a word that conveyed follows-and-is-followed-by I'd use that. But I can't think of one.