Full Idea
Instrumentalists treat the theoretical/non-theoretical and the observational/non-observational distinctions as the same, ..because they think words get their meaning by way of ostensive definition.
Clarification
Things are 'ostensively' defined by pointing to them
Gist of Idea
Instrumentalists say distinctions between observation and theory vanish with ostensive definition
Source
Alexander Bird (Philosophy of Science [1998], Ch.4)
Book Reference
Bird,Alexander: 'Philosophy of Science' [UCL Press 2000], p.130
A Reaction
To be honest, I'm not sure I quite understand this, but it sounds interesting... Ostensive definition seems to match the pragmatic spirit of instrumentalism (for which, see Idea 6778). Bird explains it all more fully.
Related Idea
Idea 6778 Instrumentalists regard theories as tools for prediction, with truth being irrelevant [Bird]