One black-and-white perspective on building software is that part of it is about mechanics and part of it is about science. The mechanics part is about wiring things up, composing smaller solutions into bigger ones, and solving any problems that arise in the process. The science part is taking problems that don’t fit well into the existing mechanisms and making a new mechanism that identifies and solves all the right puzzles.
You could look at visual and interaction design in the same way. The mechanical part is about using the available assets and mechanisms to create a visual, interactive experience on screens that humans interact with. The science is about solving a problem using ideas that people already understand or creating an idea that teaches people how to solve a problem.
The mechanical case is about knowing tools, when to use them, and how they interact with each other. The scientific case is about holding lots of state and puzzle in your head and thinking about how computers or people will interact with the system.
I’ve observed that people end up all long the spectrum. Some specialize on mechanics, others on science. The rare case that can work adeptly on both sides, even if they’re not the best at either discipline, is really fun to watch.
Adam Keys is typing 
I’d like to see you follow this idea through a bit more – interested to see examples, practical applications and implications. What’s your perspective on people who move from visual to doing more interaction design, as is commonly the case? I recently heard a statistic (cant remember exact numbers), but the gist was that overwhelmingly, UXers have design backgrounds, but UX isn’t design – it’s strategy.
I don’t know.
I think there’s still a fair amount of art in it all. As a general mantra, I like this Bukowski quote:
“An intellectual says a simple thing in a hard way. An artist says a hard thing in a simple way.”
That’s an interesting question. I haven’t worked or talked with visual designers enough to know what their mental model is like. It seems like they could succeed if they focus on how people really use computers and think about problems.
I can totally buy that UX is strategy. There are a lot of factors to take into consideration before deciding what’s important and how to tackle the important factors. That said, I think that, broadly speaking, any activity where you have to decide what to leave in and what to take out is a design discipline. In this sense, UX is a design-ish thing.
I don’t think design or development is an art in the sense of literature or music. It’s not personal, there’s no room for indulgence, it doesn’t seek to tap into emotions you might not have known were there.
Despite that, there’s room for artistic qualities. Concision, cleverness, unique composition, and conceptual integration are all things that delight me in music and software.