Full Idea
The memory, senses, and understanding are all of them founded on the imagination, or the vivacity of our ideas.
Gist of Idea
Memory, senses and understanding are all founded on the imagination
Source
David Hume (Treatise of Human Nature [1739], I.IV.7.3), quoted by Stephan Schmid - Faculties in Early Modern Philosophy 5
Book Reference
'The Faculties: a history', ed/tr. Perler,Dominic [OUP 2015], p.186
A Reaction
He seems to have in mind his theory of associations, which are not rational.