PKINCIPLES OF NATURE AND GRACE 4! I 



presently mention ( 12). Thus it is well to make dis- 

 tinction between perception, which is the inner state of 

 the Monad representing outer things, and apperception, 

 which is consciousness or the reflective knowledge of this 

 inner state, and which is not given to all souls nor to the 

 same soul at all times. It is for lack of this distinction 

 that the Cartesians have made the mistake of ignoring 

 perceptions of which we are not conscious 19 , as ordinary 

 people ignore imperceptible [insensible] bodies 1 ' . It is 

 this also that has led these same Cartesians to believe 

 that only minds [esprits] are Monads, that the lower 

 animals have no soul, and that still less are there other 

 principles of life 21 . And as they came into too great con- 

 flict with the common opinion of men in denying feeling 

 [sentiment] to the lower animals, so on the other hand 

 they conformed too much to the prejudices of the crowd 

 in confounding a prolonged unconsciousness, which comes 

 from a great confusion of perceptions, with absolute death, 

 in which all perception would cease. This has confirmed 

 the ill-founded opinion that some souls are destroyed, and 

 the bad ideas of some who call themselves free-thinkers 

 [esprits forts] and who have disputed the immortality of 

 our soul 22 . 



20 'As in body we hold that there is avrirvma and figure in 

 general, although we do not know what are the figures of im- 

 perceptible bodies ; so in the soul we hold that there is perception 

 and appetition, although we do not distinctly know the imper- 

 ceptible elements of the confused perceptions by which the im- 

 perceptible parts of bodies are expressed. . . . You ask whether 

 I believe that there are bodies which do not fall within sight. 

 Why should I not believe it ? I think ib impossible to doubt it. 

 Through microscopes we see animalculae otherwise imperceptible, 

 and the nerves of these animalculae, and other animalculae, 

 perhaps swimming in the fluid parts of these, cannot be seen. 

 The minuteness [subtiUtas] of nature goes ad infinitum.' Epistola ad 

 Bierlingium (1711) (E. 678 a ; G. vii. 501). 



121 Leibniz probably means what elsewhere, following Scholastic 

 usage, he calls ' forms/ Cf. Introduction, Part iv. p. 156. 



22 Cf. Monadology, 13. 



