DEDUCTIVE HABITS. 335 



pleted by another. Deductive reasoners, those 

 who cultivate science of whatever kind, by means 

 of mathematical and logical processes alone, may 

 acquire an exaggerated feeling of the amount 

 and value of their labours. Such employments, 

 from the clearness of the notions involved in 

 them, the irresistible concatenation of truths 

 which they unfold, the subtlety which they 

 require, and their entire success in that which 

 they attempt, possess a peculiar fascination for 

 the intellect. Those who pursue such studies 

 have generally a contempt and impatience of the 

 pretensions of all those other portions of our 

 knowledge, where from the nature of the case, or 

 the small progress hitherto made in their cultiva- 

 tion, a more vague and loose kind of reasoning 

 seems to be adopted. Now if this feeling be 

 carried so far as to make the reasoner suppose 

 that these mathematical and logical processes 

 can lead him to all the knowledge and all the 

 certainty which we need, it is clearly a delusive 

 feeling. For it is confessed on all hands, that all 

 which mathematics or which logic can do, is to 

 develope and extract those truths, as conclusions, 

 which were in reality involved in the principles 

 on which our reasonings proceeded.* And this 

 being allowed, we cannot but ask how we obtain 



* " Since all reasoning may be resolved int.o syllogisms, and 

 since in a syllogism the premises do virtually assert the conclu- 



