620 PSrCUOLOGY. 



that the Latter alternative is the true one, and that we can 

 no more intuit a duration than ive can intuit an extension^ 

 devoid of all sensible content. Just as with closed eyes we 

 perceive a dark visual field iu which a curdling play of ob- 

 scurest luminosity is always going on ; so, be we never so 

 abstracted from distinct outward impressions, we are always 

 inwardly immersed in what Wundt has somewhere called 

 the twilight of our general consciousness. Our heart-beats, 

 our breathing, the pulses of our attention, fragments of 

 words or sentences that pass through our imagination, are 

 what people this dim habitat. Now, all these processes are 

 rhythmical, and are apprehended by us, as they occur, in 

 their totality ; the breathing and pulses of attention, as 

 coherent successions, each with its rise and fall ; the lieart- 

 beats similarly, only relatively far more brief ; the words not 

 separately, but in connected groups. In short, empty our 

 minds as we may, some form of clianging process remains for 

 us to feel, and cannot be expelled. And along with the sense 

 of the process and its rhythm goes the sense of the length 

 of time it lasts. Awareness of change is thus the condition 

 on which our perception of time's flow depends ; but there 

 exists no reason to suppose that empty time's own changes 

 are sufficient for the awareness of change to be aroused. 

 The change must be of some concrete sort — an outAvard 

 or inward sensible series, or a process of attention or voli- 

 tion.* 



* I leave the text just as it was printed in the Journal of Speculative 

 Philosophy (for ' Oct. 1886 ') in 1887. Since then Munsterberg in his 

 masterly Beitrage zur experimentellen Psychologic (Heft 2, 1889) seems to 

 have made it clear what the sensible changes are by which we measure the 

 lapse of time. When the time which separates two sensible impressions is 

 less than one third of a second, he thinks it is almost entirely the avionnt to 

 which the memory-image of the first vnpression has faded when the second one 

 overtakes it, which makes us feel how wide they are apart (p. 29). When the 

 time is longer than this, we rely, he thinks, exclusively upon the feelings 

 of muscular tension and relaxation, which we are constantly receiving 

 although we give to them so little of our direct attention. These feelings 

 are primarily in the muscles by which we adapt our sense-organs in attending 

 to the signals used, some of the muscles being in the eye and ear them- 

 selves, some of them in the head, neck, etc. We here judge two time- 

 intervals to be equal when between the beginning and end of each we feel 

 exactly similar relaxations and subsequent expectant tensions of these 



