P64: Knowledge of evil is an inadequate knowledge.

Dem.: Knowledge of evil (by P8) is Sadness itself, insofar as we are conscious of it. But Sadness is a passage to a lesser perfection (by Def. Aff. III), which therefore cannot be understood through man’s essence itself (by IIIP6 and P7). Hence (by IIID2), it is a passion, which (by IIIP3) depends on inadequate ideas. Therefore (by IIP29), knowledge of this, viz.nowledge of evil, is inadequate, q.e.d.

Cor.: From this it follows that if the human Mind had only adequate ideas, it would form no notion of evil.