The title of this post and the diagram comes from Hugh Dubberly and his slidedeck about how design is centered on models and conversation and politics. Not kidding.
It’s centered on models in part because “For people to use a product successfully, they must have the same mental model (the user’s model) as that of the designer (the designer’s model).”—Don Norman
It’s centered on conversation in part because “all products are the result of conversations.”—Hugh Dubberly
It’s centered on politics in part because “The real issues, the issues that matter, are essentially political in nature. What’s important to us? What do we value? What are our values?”—Hugh Dubberly
That’s a lot of centers, so think: the intersection. It’s my paraphrase and you ought to confer with his original to get the richness of his argument, along with the references and stories he brings together. Here’s the link again to his slidedeck. I feel that for any designer it’s time well spent.