Michael Bierut at Design Observer talks about what design is, including the revelatory thought that design is about everything else.
Over the years, I came to realize that my best work has always involvedsubjects that interested me, or — even better — subjects about which I've become interested, and even passionate about, through the very process of doing design work. I believe I'm still passionate about graphic design. But the great thing about graphic design is that it is almost always about something else.
...To me, the conclusion is inescapable: the more things you're interested in, the better your work will be.
I've blogged elsewhere that I think design is terribly important to discovery, to developing new insight. But Bierut says it much, much better. Design, indeed discovery, is what you do with everything else.