Full Idea
I construe Locke's thesis that our thoughts are 'composed of ideas' as the proposal that thinking (in its central form) crucially involves processes of imagination.
Gist of Idea
Locke's view that thoughts are made of ideas asserts the crucial role of imagination
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694]), quoted by E.J. Lowe - Locke on Human Understanding III
Book Reference
Lowe,E.J.: 'Locke on Human Understanding' [Routledge 2004], p.167
A Reaction
I like this, because I am struck with how incredibly wrong Descartes was about imagination, proposing that it was some trivial and peripheral aspect of the mind (Idea 1399). "Thinking just is imagination" is a plausible slogan.
Related Idea
Idea 1399 Imagination and sensation are non-essential to mind [Descartes]