THE PRINCIPAL ACTS 391 



This being so, imagination is as much to be feared in the sciences 

 as it is indispensable in literature ; for its aberrations in the latter 

 are merely a lack of taste and reason, whereas its aberrations in the 

 former are errors ; for the imagination nearly always gives rise to 

 errors, when it is not controlled and limited by learning and reason ; 

 and if these errors are captivating, they inflict upon science an injury 

 which is often very difficult to repair. 



Yet without imagination there is no genius, and without genius 

 there is no possibility of discovering anything but facts, without 

 drawing any satisfying inferences. Now since every science is a body 

 of principles and inferences carefully deduced from observed facts, 

 genius is absolutely necessary for stating these principles and drawing 

 their inferences ; but it has to be guided by a sound judgment, and 

 kept within the limits imposed by a high degree of enlighten- 

 ment. 



Thus, although it is true that imagination is. to be feared in the 

 sciences, this only holds good when it is not controlled by a lofty and 

 enhghtened reason ; when it is so controlled, it is one of the essential 

 factors in the progress of science. 



Now the only means of limiting our imagination, so that its aberra- 

 tions may not affect the advancement of knowledge, is to allow it to 

 work only on real natural objects ; since such objects are all that 

 we can possibly know positively ; its various acts will then possess 

 a reliability that is proportional to the number of facts considered in 

 the object concerned, and to the excellence of our judgment. 



I shall conclude this section with the remark that if it is true that 

 we derive all our ideas from nature, and have none that do not come 

 originally from her, it is also true that we can modify these ideas in 

 various ways by means of our imagination, so as to create new ones 

 entirely foreign to nature ; but these latter are always either contrasts 

 to acquired ideas, or else more or less distorted images of objects the 

 knowledge of which we derive from nature alone. 



Even in the most exaggerated and extraordinary ideas of man, it 

 is impossible not to recognise their origin, by means of a close 

 examination. 



OF MEMORY. 



The Third of the Principal Faculties of the Intellect. 



Memory is a faculty of the intellectual organs ; the recollection of an 

 object or thought is an act of this faculty ; and the organ of the under- 

 standing is the seat where this wonderful act occurs, while the nervous 

 fluid by its movements in that organ is the sole agent of its occurrence. 



