Full Idea
Imagination is nothing else but sense decaying or weakened by the absence of the object.
Gist of Idea
Imagination is just weakened sensation
Source
Thomas Hobbes (De Corpore (Elements, First Section) [1655], 4.25.07)
Book Reference
Hobbes,Thomas: 'Metaphysical Writings', ed/tr. Calkins,Mary Whiton [Open Court 1905], p.121
A Reaction
This sounds more like memory than imagination. He needs to say something about unusual combinations of memories, I would have thought.