282 THE PHILOSOPHY OF BIOLOGY 



complex so, in general, is consciousness more or less 

 acute. 



Yet in the same organism consciousness is the more 

 or less acute as the actions which it performs are more 

 or less familiar. The pianist who plays scales as a 

 matter of exercise carries out most complex movements 

 of hands and wrists unconsciously and without effort, 

 but to play an unfamiliar composition for the first time 

 without error involves attention of the highest degree. 

 A girl who counts the sheets of paper coming from a 

 machine seizes a handful in one hand, and drops a 

 separate sheet between every two fingers of the other 

 hand, repeating this most difficult operation with great 

 rapidity, and counting the handfuls of sheets accurately 

 while thinking and talking deliberately about some 

 other matter. At the beginning of her work these 

 actions were clumsily performed and facility was only 

 attained by sustained attention to the movements of 

 the hands, yet with experience they become uncon- 

 sciously performed. Complex movements of the body 

 and limbs and digits, involving the co-ordinated activity 

 of numerous muscles, nerves, and nerve centres, are 

 performed at first only after a high degree of conscious 

 effort, but with each repetition of the series of move- 

 ments the animal ceases to be aware of them, or at 

 least of their difficulty. In the higher animals there 

 are, therefore, two categories of actions, (i) those un- 

 familiar actions which are difficult, and in the perform- 

 ance of which the animal becomes conscious of complex 

 muscular activities ; and (2) those habitual actions 

 which have become easy by dint of repetition, and the 

 performance of which is unattended by conscious effort. 

 Analysis of our own activities reveals these two cate- 

 gories of actions, and we have no doubt whatever that 

 the higher animals have the same feelings of difficulty 



