Full Idea
For Spinoza there are three levels of knowledge: first, sense perception or imagination, second, reasoned reflection leading to principles, and third (the highest), intuition, in which the adequacy of an idea is immediately known.
Gist of Idea
Spinoza's three levels of knowledge are perception/imagination, then principles, then intuitions
Source
report of Baruch de Spinoza (The Ethics [1675]) by Roger Scruton - Short History of Modern Philosophy §5.6
Book Reference
Scruton,Roger: 'A Short History of Modern Philosophy' [ARK 1985], p.57
A Reaction
This notion of rising levels of knowledge has an obvious background in Plato. The third level is clearly rationalist, where empiricists would probably never aspire to rise above level two. I share the empiricist suspicion of level three.