Imagination detective attached to objects (5,3)
I believe the answer is:
minds eye
'imagination' is the definition.
(mind's eye is a kind of imagination)
'detective attached to objects' is the wordplay.
'detective' becomes 'eye' (as in a private eye).
'attached to' is a charade indicator (letters next to each other).
'objects' becomes 'minds' (to mind something is to object to it happening).
'eye' after 'minds' is 'MINDS EYE'.
(Other definitions for minds eye that I've seen before include "The faculty of imagination" , "memory's required" , "contemplation" .)