NECESSITY OF IMAGINATIVE POWER. 361 



overcome the mental persistency of old associations of 

 deas, and the momentum of habitual currents of thought, 

 oefore we can conceive new ideas. 



Imagination is not a special mental faculty or mode 

 f mental action, nor a simple action of the mind like that 

 f comparison or inference, but a high degree of activity 

 f special combinations of the simple mental powers. The 

 products of its action are called conceptions, or original 

 deas, in order to distinguish them from other perceptions, 

 jrreat imaginative power is, in fact, closely associated 

 ivith genius, 1 and the two may be considered together. 



High imaginative power requires for its full exercise 

 ^reat inherited nervous impressibility for the ideas of a 

 particular subject, and a well-disciplined mind, richly 

 stored with truthful ideas relating to that subject. In 

 original scientific research, we must have inherently acute 

 senses and perception, and a fertile and rapidly-acting 

 intellect. The tendency to the particular subject is a 

 congenital gift, like the instinct of animals, and is more 

 common in subjects which, like music and painting, depend 

 upon a high degree of refinement of the senses than in 

 jthose requiring great reasoning power, because the latter 

 Idepend upon a greater variety of acquirements and more 

 intellectual action. In each case, however, the more com- 

 plete and accurate the knowledge of the particular subject, 

 the more perfect the action of the imagination ; and such 

 knowledge cannot be obtained by intuition. Truthful 

 mental conception is based upon experience, and is largely 

 limited by nature. It is only by possession of true views 

 of the great principles of nature, as well as by inherited 

 acuteness to ideas and impressions of natural phenomena, 

 that a scientific investigator is enabled to imagine and 

 discover the true hypothetical explanation of a novel 

 1 See p. 241. 



