I was taught that the Standard Model was a misnomer; that it ought to be called the Standard Theory. I'm inclined to agree, though theories and models are both indispensable in science.
Ultimately, the purpose of a model is provide local understanding of a particular phenomena. A model:
- Typically considers only fields, objects or quantities relevant to a particular phenomena
- Typically considers a particular energy scale.
- Provides local explanations of phenomena, often in terms of intuitive concepts or with metaphors (plum-pudding mode, billiard-ball model etc)
- "Truth" (i.e. scientific realism) is not the goal of modelling - understanding is the goal.
A theory, on the other hand, is supposed to be closer to the "truth":
- Typically broad in scope - considers many fields, objects and quantities relevant to multiple phenomena.
- Typically applies to many energy scales.
- Often lacks intuitive explanatory power - applying a theory to specific case may be complicated.
- "Truth" is an important goal - theories are supposed to be (approximations) to reality, rather than stories that help to understand a phenomena.
There is a reciprocal relationship between theories and models - scientists use both to develop their ideas. There are gaps in our understanding about the roles of models and theories, particularly in high-energy physics.
Indeed, returning to my opening remarks, it is unclear whether effective field theories, such as the Standard Model, play the role of theories or models, or something in between.