THE PERCEPTION OF SIGHT. 309 



cannot describe the impression in words, even to our- 

 selves. And yet it is certain that this kind of know- 

 ledge {Kennen) may attain the highest possible degree 

 of precision and certainty, and is so far not inferior 

 to any knowledge {Wissen) which can be expressed in 

 words ; but it is not directly communicable, unless the 

 object in question can be brought actually forward, or 

 the impression it produces can be otherwise represented 

 — as by drawing the portrait of a man instead of pro- 

 ducing the man himself. 



It is an important part of the former kind of know- 

 ledge to be acquainted with the particular innervation of 

 muscles, which is necessary in order to produce any eifect 

 we intend by moving our limbs. As children, we must 

 learn to walk ; we must afterwards learn how to skate or 

 go on stilts, how to ride, or swim, or sing, or pronounce a 

 foreign language. Moreover, observation of infants shows 

 that they have to learn a number of things which after- 

 wards they will know so well as entirely to forget that 

 there was ever a time when they were ignorant of them. 

 For example, everyone of us had to learn, when an 

 infant, how to turn his eyes toward the light in order to 

 see. This kind of 'knowledge' (Kennen) we also call 

 ' being able ' to do a thing (kdnnen), or ' understanding ' 

 how to do it {verstehen\ as, ' I know how to ride,' ' I am 

 able to ride,' or ' I understand how to ride.' ^ 



It is important to notice that this ' knowledge ' of the 

 effort of the will to be exerted must attain the highest 

 possible degree of certainty, accuracy, and precision, for 

 us to be able to maintain so artificial a balance as is 

 necessary for Avalking on stilts or for skating, for the singer 

 to know how to strike a note with his voice, or the 



^ The German word konnen is said to be of the same etymology as 

 kcnmn, and so their likeness in form would be explained by their likeness 

 in meaning. 



