E2P26D2
Demonstration — Part II
Latin
Cum mens humana per ideas affectionum sui corporis corpora externa contemplatur, eandem tum imaginari dicimus (vide scholium propositionis 17 hujus) nec mens alia ratione (per propositionem præcedentem) corpora externa ut actu existentia imaginari potest. Atque adeo (per propositionem 25 hujus) quatenus mens corpora externa imaginatur, eorum adæquatam cognitionem non habet. Q.E.D.
English (Elwes 1883)
When the human mind regards external bodies through the ideas of the modifications of its own body, we say that it imagines (see II. xvii. note); now the mind can only imagine external bodies as actually existing. Therefore (by II. xxv.), in so far as the mind imagines external bodies, it has not an adequate knowledge of them. Q.E.D.
Modern English
When the human mind regards external bodies through the ideas of its body's affections, we say it imagines those bodies (E2P17S). And the mind can regard external bodies as actually existing in no other way (E2P26). Therefore, insofar as the mind imagines external bodies, it does not have an adequate knowledge of them (E2P25). Q.E.D.