IMPORT OF PROPOSITIONS. 119 



the two ideas corresponding to the subject and predi- 

 cate (instead of the relation between the two pheno- 

 mena which they respectively express), seems to me 

 one of the most fatal errors ever introduced into the 

 philosophy of Logic ; and the principal cause why the 

 theory of the science has made such inconsiderable 

 progress during the last two centuries, The treatises 

 on Logic, and on the branches of Mental Philosophy 

 connected with Logic, which have been produced since 

 the intrusion of this cardinal error, though sometimes 

 written by men of extraordinary abilities and attain- 

 ments, almost always tacitly imply a theory that the 

 investigation of truth consists in contemplating and 

 handling our ideas, or conceptions of things, instead 

 of the things themselves : a process by which, I will 

 venture to affirm, not a single truth ever was arrived 

 at, except truths of psychology, a science of which 

 Ideas or Conceptions are avowedly (along with other 

 mental phenomena) the subject-matter. Meanwhile, 

 inquiries into every kind of natural phenomena were 

 incessantly establishing great and fruitful truths on the 

 most important subjects, by processes upon which these 

 views of the nature of Judgment and Reasoning threw 

 no light, and in which they afforded no assistance 

 whatever. No wonder that those who knew by prac- 

 tical experience how truths are come at, should deem 

 a science futile, which consisted chiefly of such specu- 

 lations. What has been done for the advancement of 

 Logic since these doctrines came into vogue, has been 

 done not by professed logicians, but by discoverers in 

 the other sciences ; in whose methods of investigation 

 many great principles of logic, not previously thought 

 of, have successively come forth into light, but who 

 have generally committed the error of supposing that 

 nothing whatever was known of the art of philoso- 



