On Thu, Oct 1, 2009 at 9:53 AM, Andrew Coppin <andrewcoppin@btinternet.com> wrote:

Sure. But what is a computer program? It's a *list of instructions* that tells a computer *how to do something*. And yet, the Haskell definition of sum looks more like a definition of what a sum is rather than an actual, usable procedure for *computing* that sum. (Of course, we know that it /is/ in fact executable... it just doesn't look it at first sight.)

Is it? The list of instruction is just an abstraction layer built on top of purely physical process of electrons and transistors; I'm not sure how much imperativeness remains at this level? Not to mention the quantum mechanical processes that take place... And that are also just mathematical models... I mean, it really depends from which angle and at which detail you look at it, no?