What is science?

Today I received an e-mail from a collaborator of mine stating

...our community doesn't reward engineering effort but instead scientific advances.

The context was a discussion of what is publishable in scientific software development. This got me thinking about what really is the difference between science and engineering, and what is the difference between publishable advances and the rest of the work that scientists do.

After some thought I've concluded that this difference is in many respects artificial and purely a function of one's discipline (or even sub-discipline). To take algorithmic complexity as an example:

-To a complexity theorist, a reduction in complexity from 1000N^3 to 3N^2 would be considered "engineering effort": after all, either one is in P, right?

-To an applied mathematician, the above result would be considered a fabulous scientific advance, but a further reduction from 3N^2 to 2N^2 might not be deemed publishable.

-To a chemist, say, who needs to run the algorithm with 10000 different parameter sets, even a 10% improvement might be considered a valuable scientific advance.

Of course, to a pure mathematician any algorithm for solving the problem is an engineering detail; the only scientific aspect is proving the existence of a unique solution.

All of these advances may be important steps leading from an abstract idea to a technological breakthrough that benefits non-scientists. I think it's okay that all the above researchers are only interested in one particular step in this chain of advances. What's detrimental, however, is the inability to recognize that the other steps in this chain are valuable. This kind of bigotry is, in my experience, rather common among scientists.

Edit: Ironically, the quote at the beginning came from a person whose title is "Professor of Engineering".