Critically Engaging With Models (DDD Europe Keynote)

Our worldviews are grown from other people’s models. How do we control what models we let in?

By Rebecca Wirfs-Brock and Mathias Verraes
Published on 24 January 2023

Here’s the video of Rebecca Wirfs-Brock & my keynote at Domain-Driven Design Europe 2022, where we talk about the ideas presented in our essay “Critically Engaging with Models”, also available as an e-book on Leanpub.

Watch on YouTube


Models, whether for a software system, a development process, diseases, political systems, or otherwise, are a way to look at (a part of) the world. They make a choice about what is important, what categories we classify things in, what we see, what’s invisible, what’s valued, or even what’s valid. They are reductionist, that is, they only show a selection of the subject they’re describing. And they are biased: They implicitly reflect the assumptions, constraints, and values of the model’s author.

Most of the time, when you adopt a model created by someone else, you assimilate it into your worldview without much thought. You acquire a new way of seeing something. But when you do that, you may not understand the model’s limitations.

You can choose to look at someone’s model more intentionally. You can critically assess whether this model fits your needs. If you’re looking at a model for the first time, you can use that fresh perspective to see what the model includes and what it leaves out. Models are a powerful lens for perceiving a subject, and we should be deliberate when wielding them. This talk gives you tools for critically evaluating any models that come your way.

Design and Reality

Essays on Software Design

by Mathias Verraes & Rebecca Wirfs-Brock

Get it on Leanpub

“Happily purchased. Handy to have these in one place. Thank you!”
— Kent Beck

“Excellent new thinking on Domain-Driven Design. It's full of real practical experience in getting the most value from domain modelling. Just like the Eric Evans' DDD book, this gives more insight each time you read it.”
— Ian Russell