Berkeley is widely held to be a scientific instrumentalist, but the scope of his ­instrumentalism has been repeatedly brought into question. Some have asserted that Berkeley capitulated wholesale to a form of external realism at the end of his life, others have supposed principled reasons for thinking that Berkeley is an instrumen­talist about some things and not about others. Lisa Downing, for instance, has argued that Berkeley is an instrumentalist about forces but not about corpuscles, and Douglas Jesseph contends that Berkeley rejects mathematical instrumentalism despite being a stronger instrumentalist in the sciences.