"Scientific knowledge derives from a mode of inquiry into the nature of the universe that has been successful and of great consequence. Science focuses on (i) observing the natural world and (ii) formulating testable and refutable hypotheses to derive deeper explanations for observable phenomena. When evidence is sufficiently compelling, scientific theories are developed that account for and explain that evidence, and predict the likely structure or process of still unobserved phenomena."
-- IAP Statement on the Teaching of Evolution
That one elegant paragraph beautifully encompasses what is and what is not science, and cuts through to the very nature of science. The common creationist/IDist whine is that "macroevolution hasn't been observed, bla bla bla". Well, of course this is nonsense. This statement was evidently written by a people with their finger on the pulse of this issue. Well done!