before_sent:  Our central contribution is a definition of what it means for a representation to be modular and an experimental method for assessing the extent to which a system's solution is modular in this general sense .
before_sent_with_intent: <clarity>  Our central contribution is a definition of what it means for a representation to be modular and an experimental method for assessing the extent to which a system's solution is modular in this general sense .
after_sent:  Our central contribution is a new experimental method called 'interchange interventions', in which systematic manipulations of model-internal states are related to causal effects on their outputs, thereby allowing us to identify modular structure .