CLASSIFICATION. 67 



fessor G-. 0. Foster in Watts's ' Dictionary of Chemistry/ 

 But the present theory of classification was not reached 

 until at least three previous false systems had been long 

 entertained. And though there is much reason to believe 

 that the present system of classification according to 

 atomicity is substantially correct, many errors may yet 

 be discovered in the details of the grouping. 



Symbolic Statement of the Theory of Classification. 



The whole theory of classification can be explained in 

 the most complete and general manner, by reverting for 

 a time to the use of the Logical Abecedarium, which was 

 found to be of supreme importance in Formal Logic (vol. i. 

 p. 109). That form expresses in fact the necessary classi- 

 fication of all objects and ideas as depending on the laws 

 of thought, and there is no point concerning the purpose 

 and methods of classification which may not be explained 

 most precisely by the use of letter combinations, the only 

 inconvenience being the somewhat abstract and repulsive 

 form in which the subject is thus represented. 



If we pay regard only to three qualities or circum- 

 stances in which things may resemble each other, namely 

 the qualities A, B, C, then there are according to the laws 

 of thought eight possible classes of objects. If there exist 

 objects belonging to aU these eight classes, thus indicated, 



ABC aBC 



ABc aBc 



A6C abC 



Abe abc 



it follows that the qualities A, B, C are subject to no 

 conditions except the primary laws of thought and nature 

 (vol. i. p. 6). There is then no special law of nature to 



