We use models to think about everything.
DRAFT These rough notes need to be sorted out and expanded.
Note: Philosophically, entities like tasks do not exist in the physical world, so they are mental models of how humans understand the universe. However, these models are considered involuntary and unconscious - we use them naturally; it seems unlikely that we can change so fundamental a feature of human cognition to the benefit of design anytime soon. So we limit our discussion to conscious models that we can rationalize about.
A model is:
If a model of something were perfect, it would be indistinguishable from the thing itself. So every model is imperfect.
But that's okay. We use models to capture only those elements of a thing that are interesting to us for some reason.
Models can be formal, informal, or somewhere in between.
A design is a just a model of the thing you're designing. It won't be perfect. But it can be good enough to let a manufacturer create or implement the product.
This raises the question: how much information must the design contain so that it can be made?
TODO Describe consequences and counter-indications.