4 INDUCTION. 



appearing, who profess either to have solved the problem, or 

 to suggest modes in which it may one day be solved. Even 

 where pretensions of this magnitude are not made, the cha- 

 racter of the solutions which are given or sought of particular 

 classes of phenomena, often involves such conceptions of what 

 constitutes explanation, as would render the notion of explain- 

 ing all phenomena whatever by means of some one cause or 

 law, perfectly admissible. 



2. It is therefore useful to remark, that the ultimate 

 Laws of Nature cannot possibly be less numerous than the 

 distinguishable sensations or other feelings of our nature ; 

 those, I mean, which are distinguishable from one another in 

 quality, and not merely in quantity or degree. For example ; 

 since there is a phenomenon sui generis, called colour, which 

 our consciousness testifies to be not a particular degree of some 

 other phenomenon, as heat or odour or motion, but intrinsi- 

 cally unlike all others, it follows that there are ultimate laws 

 of colour ; that though the facts of colour may admit of ex- 

 planation, they never can be explained from laws of heat or 

 odour alone, or of motion alone, but that however far the 

 explanation may be carried, there will always remain in it a 

 law of colour. I do not mean that it might not possibly be 

 shown that some other phenomenon, some chemical or mecha- 

 nical action for example, invariably precedes, and is the cause 

 of, every phenomenon of colour. But though this, if proved, 

 would be an important extension of our knowledge of nature, it 

 would not explain how or why a motion, or a chemical action, 

 can produce a sensation of colour; and however diligent might 

 be our scrutiny of the phenomena, whatever number of hidden 

 links we might detect in the chain of causation terminating in 

 the colour, the last link would still be a law of colour, not a law 

 of motion, nor of any other phenomenon whatever. Nor does 

 this observation apply only to colour, as compared with any 

 other of the great classes of sensations ; it applies to every 

 particular colour, as compared with others. White colour can 

 in no manner be explained exclusively by the laws of the pro- 

 duction of red colour. In any attempt to explain it, we cannot 



