PHILOSOPHY OF ZOOLOGY. 



The ideas on which the imagination exercises its powers 

 with the greatest success, are those which the memory can 

 recall with the greatest distinctness, such as those obtained 

 by the aid of the sense of sight and touch. But the ideas pro- 

 duced by the impressions of the other senses-, such ashearing, 

 taste, or smell, cannot be so readily recollected, and at best 

 but obscurely ; hence the imagination cannot operate upon 

 them with any degree of success. The combination of the 

 ideas resulting from these last impressions, with new ob- 

 jects, is seldom intimate. When, in works of fiction, they 

 appear to be so, it is because we deceive ourselves with the 

 signs of the sensations, which we are able to combine in 

 any mariner we please, while we are incapable of combin- 

 ing the ideas which they represent. 



By means of imagination, thus exercised on former im- 

 pressions, we are able to produce new ones, in a greater 

 degree, perfect or imperfect, agreeable or disagreeable, than 

 any which we .have ever experienced. 



But if we restrict the operations of imagination to the 

 decomposition or combination of ideas which we have ac- 

 tually obtained by sensation, we render doubtful its claims 

 to rank as a distinct faculty of the mind, and greatly limit 

 its usefulness as an instrument in the acquisition of know- 

 ledge. It is not merely a retrospective, but a prospective 

 power. By the help of memory, we recall past impressions ; 

 by the help of imagination, in the exercise of this second 

 function, we, as it were, render future impressions present. 

 It is true that these pictures of futurity are formed of the 

 materials of past impressions, but they are always in a new 

 state of combination with regard to time. Sometimes they 

 arc more disagreeable than those of the past, when the 

 mind is torn with despair. In other instances, more agree- 

 able, when they are generated under the cheering influence 

 of nope. Some of the pictures of the imagination, as those 



