PREFACE. VJ1 



through some one of the common treatises on Logic; 

 among which that of Archbishop Whately is, on every 

 account, to be preferred. And the Third Book presup- 

 poses some degree of acquaintance with the most 

 general truths of mathematics, as well as of the prin- 

 cipal branches of physical science, and with the evi- 

 dence on which those doctrines rest. Among books 

 professedly treating of the mental phenomena, a 

 previous familiarity with the earlier portion of Dr. 

 Brown's Lectures, or with his treatise on Cause and 

 Effect, would, though not indispensable, be advan- 

 tageous ; that philosopher having, in the author's 

 judgment, taken a more correct view than any other 

 English writer on the subject, of the ultimate intel- 

 lectual laws of scientific inquiry; while his unusual 

 powers of popularly stating and felicitously illustrating 

 whatever he understood, render his works the best 

 preparation which can be suggested, for speculations 

 similar to those contained in this Treatise. 



