J/.LV THE INTERPRETER OF NATURE. 203 



between its waking and its dreaming experiences ; or, if it is 

 now and then puzzled to answer the qucbiion, &quot; Did this really 

 happen, or did I dream it?&quot; the perplexity arises from the 

 consciousness that it might have happened. And every healthy 

 mind, finding its own experiences of its waking state not only 

 self-consistent, but consistent with the experiences of others, 

 accepts them as the basis of its beliefs, in preference to even 

 the m &amp;gt;st vivid recollections of its dreams. 



The lunatic pauper who regards himself as a king, the asylum 

 in which he is confined as a palace of regal splendour, and 

 his keepers as obsequious attendants, is so &quot; possessed &quot; by the 

 conception framed by his disordered intellect, that he does pro 

 ject it out of himself into his surroundings ; his refusal to admit 

 the corrective teaching of common sense being the very essence 

 of his malady. And there are not a few persons abroad in the 

 world, who equally resist the teachings of educated common 

 sense, whenever they run counter to their own preconceptions ; 

 and who may be regarded as in so far affected with what I once 

 heard Mr. Carlyle pithily characterize as a &quot; diluted insanity.&quot; 



It has been asserted, over and over again, of late years, by 

 a class of men who claim to be the only true interpreters of 

 Nature, that we know nothing but matter and the laws of matter, 

 and that force is a mere fiction of the imagination. May it not 

 be affirmed, on the other hand, that while our notion of matter 

 is a conception of the intellect, force is that of which we have 

 the most direct perhaps even the only direct cognizance? As 

 I have already shown you, the knowledge of resistance and of 

 weight which we gain through our tactile sense is derived from 

 our own perception of exertion ; and in vision, as in hearing, 

 it is the force with which the undulations strike the sensitive 

 surface that affects our consciousness with sights or sounds. 

 True it is that in our visual and auditory sensations, we do not, 

 as in our tactile, directly cognosce the force which produces 

 them ; but the physicist has no difficulty in making sensible 

 to us indirectly the undulations by which sound is propagated, 

 and in proving to our intellect that the force concerned in the 

 transmission of light is really enormous.* 



* See Sir John Hcrschcl s &quot; Familiar Lectures on Scientific Subjects.&quot; 



