E2P33D
Demonstration — Part II
Latin
Si negas, concipe si fieri potest, modum positivum cogitandi qui formam erroris sive falsitatis constituat. Hic cogitandi modus non potest esse in Deo (per propositionem præcedentem); extra Deum autem etiam nec esse nec concipi potest (per propositionem 15 partis I). Atque adeo nihil potest dari positivum in ideis propter quod falsæ dicuntur. Q.E.D.
English (Elwes 1883)
If this be denied, conceive, if possible, a positive mode of thinking, which should constitute the distinctive quality of falsehood. Such a mode of thinking cannot be in God (II. xxxii.); external to God it cannot be or be conceived (I. xv.). Therefore there is nothing positive in ideas which causes them to be called false. Q.E.D.
Modern English
Deny this if you can: conceive, if possible, a positive mode of thinking that constitutes the form of error or falsehood. Such a mode of thinking cannot exist in God (E2P32). But outside God it also cannot exist or be conceived (E1P15). Therefore there is nothing positive in ideas that causes them to be called false. Q.E.D.