90 HABIT AND INTELLIGENCE. [chap. 



habit, the oftener they are repeated the easier they become, 

 ■until at last, in many cases, they cease to need any co- 

 operation of the will or of the conscious attention. They 

 have of course to be voluntarily set going, but when set 

 going they are continued consensually ; the stimulus and 

 guide to each successive action of the muscles being some- 

 times the action next before it, sometimes the sight of the 

 work or the instrument before the workman. Some musi- 

 cians become able to perform in this way, the stimulus of 

 sense being given either by the sound of the successive 

 notes, or by the sight of the printed music. I have stated 

 this before, but what I wish to point out now is the 

 perfect similarity between this process and the process 

 by which we learn our own language ; or, in more general 

 terms, between the process of acquiring motor habits, and 

 the process of acquiring purely mental associations. I 

 have shown that, in order to have the association between 

 words and their meanings in an available form in the 

 mind, the residua of the impressions of all the times 

 we have heard any word must coalesce in the mind into 

 a practically single residuum ; and this is done by for- 

 getting the merely accidental circumstances under which 

 we have heard each word. Just so in learning an art. 

 Before it can be consensually performed the memory of 

 each separate time that it has been practised must be 

 lost, and the residua of them all must coalesce into one, 

 which single residuum constitutes the acquired habitual 

 power. 

 Moral The necessity under which we are of forgetting is good 



fo^rgetting. ^^^' ^^ ™ another way. Our Kfe and oui- duties are in the 

 present, and it would be bad for us were our thoughts to 

 be too much in the past ; but this is for the most part for- 

 bidden by the law of the certain though slow and gradual 

 fading away of all impressions which are not renewed. It 

 is in virtue of this law that time mitigates grief, even 

 when no nobler cause is at work.^ 



1 " "We forget because we must, 

 And not because we will." 



SIattiiew Arnold. 



