E2P29C
Corollary — Part II
Latin
Hinc sequitur mentem humanam quoties ex communi naturæ ordine res percipit, nec sui ipsius nec sui corporis nec corporum externorum adæquatam sed confusam tantum et mutilatam habere cognitionem. Nam mens se ipsam non cognoscit nisi quatenus ideas affectionum corporis percipit (per propositionem 23 hujus). Corpus autem suum (per propositionem 19 hujus) non percipit nisi per ipsas affectionum ideas per quas etiam tantum (per propositionem 26 hujus) corpora externa percipit atque adeo quatenus eas habet, nec sui ipsius (per propositionem 29 hujus) nec sui corporis (per propositionem 27 hujus) nec corporum externorum (per propositionem 25 hujus) habet adæquatam cognitionem sed tantum (per propositionem 28 hujus cum ejus scholio) mutilatam et confusam. Q.E.D.
English (Elwes 1883)
Hence it follows that the human mind, when it perceives things after the common order of nature, has not an adequate but only a confused and fragmentary knowledge of itself, of its own body, and of external bodies. For the mind does not know itself, except in so far as it perceives the ideas of the modifications of body (II. xxiii.). It only perceives its own body (II. xix.) through the ideas of the modifications, and only perceives external bodies through the same means; thus, in so far as it has such ideas of modification, it has not an adequate knowledge of itself (II. xxix.), nor of its own body (II. xxvii.), nor of external bodies (II. xxv.), but only a fragmentary and confused knowledge thereof (II. xxviii. and note). Q.E.D.
Modern English
Hence it follows that, whenever the human mind perceives things according to the common order of nature, it has not an adequate but only a confused and fragmented knowledge of itself, of its own body, and of external bodies. For the mind does not know itself except insofar as it perceives the ideas of the affections of the body (E2P23). It perceives its own body (E2P19) only through those very ideas of affections, and through them alone (E2P26) it also perceives external bodies. So insofar as it has these ideas of affection, it has not an adequate knowledge of itself (E2P29), nor of its own body (E2P27), nor of external bodies (E2P25), but only a fragmented and confused knowledge (E2P28). Q.E.D.