There's an even easier way to say it: just as we copied birds by inventing airplanes; we're mimicking natural computation through computers.
Computation, as a principle, isn't a human invention and brains aren't the only or best example found in nature.
We've just started to realize this.
[WS:] Pardon my ignorance, but something does not compute here. Computation - or executing mathematical functions - is processing ideas held in human consciousness, so how can it exist naturally, outside that consciousness? Computers compute in a fundamentally same way as the abacus does - the move objects (electrons or beads) According to patterns imposed on them by the human mind which then interprets the outcomes of those movements as concepts (i.e. quantity.) In the same vein, human mind interprets other movements of natural objects as the concept of "causality." But just as causality does not exist in nature i.e. outside the human consciousness but rather it is 'added' so to speak as an organizing principle to natural phenomena (or rather perceptions thereof) - the same applies to computation and its outcome - the concept of quantity, no?
Maybe I am missing something, but this whole thing smacks of old Platonic idealism (or the realist position on the universals http://en.wikipedia.org/wiki/Universals) wrapped in the computer jargon.
Wojtek