DEFINITION AND PROVINCE OF LOGIC. 7 



of the primitive data, or of the conclusions which can 

 be drawn therefrom. 



With the original data, or ultimate premisses of 

 our knowledge; with their number or nature, the 

 mode in which they are obtained, or the tests by 

 which they may be distinguished ; logic, in a direct 

 way at least, has, in the sense in which I conceive the 

 science, nothing to do. These questions are partly 

 not a subject of science at all, partly that of a very 

 different science. 



Whatever is known to us by consciousness, is 

 known beyond possibility of question. What one 

 sees, or feels, whether bodily or mentally, one cannot 

 but be sure that one sees or feels. No science is 

 required for the purpose of establishing such truths ; 

 no rules of art can render our knowledge of them 

 more certain than it is in itself. There is no logic for 

 this portion of our knowledge. 



But we may fancy that we see or feel what we 

 in reality infer. Newton saw the truth of many pro- 

 positions of geometry without reading the demonstra- 

 tions, but not, we may be sure, without their flashing 

 through his mind. A truth, or supposed truth, which 

 is really the result of a very rapid inference, may 

 seem to be apprehended intuitively. It has long been 

 agreed by philosophers of the most opposite schools, 

 that this mistake is actually made in so familiar an 

 instance as that of the eyesight. There is nothing 

 which we appear to ourselves more directly conscious 

 of, than the distance of an object from us. Yet it 

 has long been ascertained, that what is perceived by 

 the eye, is at most nothing more than a variously 

 coloured surface ; that when we fancy we see distance, 

 all we really see is certain variations of apparent size, 

 and more or less faintness of colour; and that our 



