Full Idea
The mind has no power to produce any simple idea.
Gist of Idea
The mind cannot produce simple ideas
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.31.02)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.375
A Reaction
These must all come from experience, implying to common empirical view (spelled out better by Hume) that that a priori concerns only combinations of ideas which we already possess. The 'conceptual' notion of a priori is consistent with this.