Knowledge

To every idea there corresponds an ideatum.

Ideas may be divided into inadequate ideas and adequate ideas. Inadequate ideas are ideas that correspond to states of my body. Adequate ideas are ideas that correspond to the things themselves. (The term "adequate" for Spinoza corresponds to Descartes's "clear and distinct").

There are three levels of cognition for Spinoza:

(1) Imagination or opinion (from sense experience)

(2) Common notions (science and mathematics)

(3) Intution ["Scientia intuitiva"] (philosophy)

"Cognition of the first kind is the only cause of falsity... while cognition of the second and third kinds is necessarily true."