Conjectures on the proximate Cause of Sleep. 255 



With respect to the former solution of the difficulty, viz. that 

 the disturbed state of our rest may prevent the total cessation of 

 the power of attention, or, in other words, that we are not quite 

 asleep during dreams, (which by the way appears the most pre- 

 valent opinion entertained at present on the subject,) it is only 

 necessary to consider the difference between sleeping and waking, 

 and reflect on our daily experience, to subvert the position. So 

 long as we sleep, we are, with some singular exceptions, either 

 totally insensible, or sensible only of internal sensations. In the 

 transition from sleeping to waking, we are perhaps passively and 

 involuntarily sensible of external impressions. And when these 

 force themselves on our attention, or when we can voluntarily 

 attend to them, from that moment we are fully awake. Nor are 

 Vfe conscious of being awake until we perceive those impressions, 

 whether by compulsion, or with our will. Sometimes we notice 

 the very moment this occurrence takes place ; but in general, if 

 we are not suddenly awakened, we perceive our sleep gradually 

 retiring — we are reluctant to resign its embraces ; we cling to it 

 as long as we can ; thoughts pass in (Crowded trains through our 

 minds ; yet these thoughts are not dreams. They assume no 

 bodily shape or visionary semblance — we regard them as we do 

 the current of our waking reflections, we direct their course as 

 we please, and we know that we can break through the dubious 

 remnant of our sleep, the moment that we will. It is otherwise 

 when we actually sleep. The generality of our thoughts assume 

 a corporeal appearance, and pass in fantastic procession before 

 U9. If our dream be terrific, we struggle to escape from the ob- 

 . ject of horror, and that struggle awakes us. Once to a certain 

 extent awake, we banish with an effort the little residue of sleep; 

 that effort is an act of the will; but whether our previous visionary 

 struggle can also be ascribed to its power, is a question too in- 

 volved for me to disentangle. 



Yet I am tempted to venture a reflection which, upon the prin- 

 ciples of the new philosophy, may lead to a solution of the diffi- 

 culty. If a single organ be awake, and a single motive be pre- 

 sented to it, it acts in obedience to that motive without choice, 

 without judgement, without a decision, and, of course, without 

 any intervention of the will. But if two motives offer themselves 

 to the faculty in question, and it chooses between them, or if 

 two organs are awake, .ind judge between the claims of two op- 

 posite motives, one applicable to this, and the other to that pro- 

 pensity or sentiment, and that a decision is the result, whether 

 to act or to forbear, to pursue or to fly, this decision, though in 

 a dream, appears to be an act of the will. It would be called 

 80 without hesitation, if these operations happened to take place 



during 



