LOGIC AS THE ESSENCE OF PHILOSOPHY 43 



of things about Socrates that he was an Athenian, that 

 he married Xantippe, that he drank the hemlock there 

 is a common constituent, namely Socrates, in all the pro- 

 positions I enunciate, but they have diverse forms. If, 

 on the other hand, I take any one of these propositions 

 and replace its constituents, one at a time, by other con- 

 stituents, the form remains constant, but no constituent 

 remains. Take (say) the series of propositions, " Socrates 

 drank the hemlock," " Coleridge drank the hemlock," 

 " Coleridge drank opium," " Coleridge ate opium." The 

 form remains unchanged throughout this series, but all 

 the constituents are altered. Thus form is not another 

 constituent, but is the way the constituents are put 

 together. It is forms, in this sense, that are the proper 

 object of philosophical logic. 



It is obvious that the knowledge of logical forms is 

 something quite different from knowledge of existing 

 things. The form of " Socrates drank the hemlock ' is 

 not an existing thing like Socrates or the hemlock, nor 

 does it even have that close relation to existing things 

 that drinking has. It is something altogether more 

 abstract and remote. We might understand all the 

 separate words of a sentence without understanding the 

 sentence : if a sentence is long and complicated, this is 

 apt to happen. In such a case we have knowledge of the 

 constituents, but not of the form. We may also have 

 knowledge of the form without having knowledge of the 

 constituents. If I say, " Rorarius drank the hemlock," 

 those among you who have never heard of Rorarius (sup- 

 posing there are any) will understand the form, without 

 having knowledge of all the constituents. In order to 

 understand a sentence, it is necessary to have knowledge 

 both of the constituents and of the particular instance of 

 the form. It is in this way that a sentence conveys 



