INTRODUCTION. 11 



The Process of Inference. 



The fundamental action of our reasoning faculties 

 consists in inferring or carrying to a new instance of a 

 phenomenon whatever we have previously known of its 

 like, analogue, equivalent or equal. Sameness or identity 

 presents itself in all degrees, and is known under various 

 names ; but the great rule of inference embraces all 

 degrees, and affirms that so far as there exists samene^-- 

 identity or likeness, what is true of one thing will be tnn-. 

 of the other. The great difficulty of reasoning doubtless 

 consists in ascertaining that there does exist a sufficient 

 degree of likeness or sameness to warrant an intended 

 inference ; and it will be our main task to investigate the 

 conditions under which the inference is valid. In this 

 place I wish to point out that there is something common 

 to all acts of inference however different their apparent 

 forms. The one same rule lends itself to the most diverse 

 applications. 



The simplest possible case of inference, perhaps, occurs 

 in the use of a pattern, example, or, as it is commonly 

 called, a sample. To prove the exact similarity of two 

 portions of commodity, w r e need not bring one portion 

 beside the other. It is sufficient that we cut a sample 

 which exactly represents the texture, appearance, and 

 general nature of one portion, and according as this 

 sample agrees or not with the other, so will the two 

 portions of commodity agree or differ. Whatever is true 

 as regards the colour, texture, density, material of the 

 sample will be true of the goods themselves. In such 

 cases likeness of quality is the condition of inference. 



Exactly the same mode of reasoning holds true of 

 magnitude and figure. To compare the size of two 

 objects, we need not lay them alongside each other. A 



