In a new post to his site Paul Jones wonders out loud about why developers think MVC is an application architecture versus just a user interface pattern.

I’ve pointed out before that Model-View-Controller is a user interface pattern, not an application architecture. But why would PHP developers get the idea that MVC is an application architecture in the first place?

[...] I used to think that MVC was an application architecture. Even after reading Fowler’s POEAA and seeing that MVC was for the user interface, I figured that meant I was doing “user interface applications.” But that was not quite right; it would have been more accurate to say that I had been mixing the concerns of user interface with the underlying core application.

He suggests that the reason MVC is commonly thought of as an architecture is because of the "flow" most PHP developers follow in their learning and development practices. Starting from "page scripts" where things are all mashed together, a developer then learns about the separation of concerns and how MVC helps splitting up the application easier. Paul includes a reminder, though, that the "user interface" isn't really just the frontend parts (HTML, CSS, JS) but the HTTP request/response to and from the application.