CHAP. I.] NATURE AND DESIGN OF THIS WORK. 3 



may be added, in importance, to the practical objects, with the 

 pursuit of which they have been historically associated. To un- 

 fold the secret laws and relations of those high faculties of 

 thought by which all beyond the merely perceptive knowledge 

 of the world and of ourselves is attained or matured, is an object 

 which does not stand in need of commendation to a rational 

 mind. 



3. But although certain parts of the design of this work have 

 been entertained by others, its general conception, its method, 

 and, to a considerable extent, its results, are believed to be ori- 

 ginal. For this reason I shall offer, in the present chapter, some 

 preparatory statements and explanations, in order that the real 

 aim of this treatise may be understood, and the treatment of its 

 subject facilitated. 



It is designed, in the first place, to investigate the fundamen- 

 tal laws of those operations of the mind by which reasoning is 

 performed. It is unnecessary to enter here into any argument to 

 prove that the operations of the mind are in a certain real sense 

 subject to laws, and that a science of the mind is therefore possible. 

 If these are questions which admit of doubt, that doubt is not 

 to be met by an endeavour to settle the point of dispute d priori, 

 but by directing the attention of the objector to the evidence of 

 actual laws, by referring him to an actual science. And thus the 

 solution of that doubt would belong not to the introduction to 

 this treatise, but to the treatise itself. Let the assumption be 

 granted, that a science of the intellectual powers is possible, and 

 let us for a moment consider how the knowledge of it is to be 

 obtained. 



4. Like all other sciences, that of the intellectual operations 

 must primarily rest upon observation, the subject of such ob- 

 servation being the very operations and processes of which we 

 desire to determine the laws. But while the necessity of a foun- 

 dation in experience is thus a condition common to all sciences, 

 there are some special differences between the modes in which 

 this principle becomes available for the determination of general 

 truths when the subject of inquiry is the mind, and when the 

 subject is external nature. To these it is necessary to direct 



attention. 



B 2 



