240 THE SCIENCE OF LOGIC 



be absurd to say that because conversion is a strictly formal process, we must 

 therefore convert propositions by its rules, according to their forms as A, E, 

 or I. Logic investigates the actual nature and procedure of our thought ; and 

 when we find that our thought is not governed by the bare form of a judgment 

 irrespective of its contents, it is no use to pretend otherwise. . . . This is 

 said not in order to discredit the abstract and formal treatment of conversion, 

 which is sound within its limits ; but in order to emphasize the fact that the 

 form and matter (or the form and content) of thought are not capable of sepa 

 rate consideration, like the mould and the pudding : what from one point of 

 view is form is from another matter, and the same form in different kinds of 

 content is not altogether the same, any more than is the same genus in different 

 species. The importance of this fact must excuse the reiteration of it ; mean 

 while in a text-book of Logic, as of any other science, we must consider typical 

 cases, with a general caveat that the subject is thereby artificially simplified.&quot; * 



The following examples will help to illustrate the foregoing paragraphs, and 

 to disclose some possible pitfalls to the beginner: &quot;All water contains air,&quot; 

 does not convert to &quot; All air contains water,&quot; or to &quot; Some air contains water,&quot; 

 or to &quot; Some air is contained by water,&quot; but to &quot; Something that contains air 

 is water &quot;. &quot; He jests at scars who never felt a wound &quot; does not convert to 

 &quot; Some scars are jested at by him who,&quot; etc., or to &quot; Some scars are jests to 

 him who,&quot; etc., or to &quot; Some jests at scars are made by him who,&quot; etc., or 

 to &quot; Some scars jest at him who (!),&quot; etc., but to &quot; Some who jest at scars are 

 people who have never felt a wound &quot;. 



&quot; John struck James &quot; does not convert to &quot; James struck John,&quot; but to 

 &quot; Some person who struck James is John &quot;. &quot; The poor have few friends &quot; 

 converts to &quot; Some who have few friends are (the) poor &quot;. &quot; Great is Diana of 

 the Ephesians &quot; converts to &quot; Some great being is Diana of the Ephesians &quot;. 

 &quot;A stitch in time saves nine &quot; does not convert to &quot; Nine stitches save a stitch 

 in time (!),&quot; or even to &quot; Nine stitches are saved by a stitch in time,&quot; but only 

 to &quot; Some (one) way of saving (or something that saves) nine stitches is a stitch 

 in time &quot;. &quot; Whatever is immortal is not material &quot; converts to &quot; Whatever 

 is material is not immortal &quot;. &quot; Non omnis moriar&quot; means &quot; Some part of 

 me is immortal,&quot; and converts to &quot; Something immortal is part of me &quot;. &quot; All 

 men have not faith &quot; means &quot; Some men have not faith,&quot; and is therefore 

 inconvertible. Similarly &quot; All is not gold that glitters &quot; means &quot; Some glitter 

 ing things are not gold,&quot; and is inconvertible. &quot; Not everyone that saith unto 

 me, Lord, Lord, shall enter into the kingdom of heaven &quot; means &quot; Some 

 who say unto me, Lord, Lord, shall not enter the kingdom of heaven,&quot; and is 

 inconvertible. But these O propositions all yield contrapositives, as we shall 

 see presently (119). We can, for example, infer from the last-mentioned pro 

 position &quot; Some who shall not enter into the kingdom of heaven are people 

 who say unto me Lord, Lord &quot;. 



&quot; Life every man holds dear &quot; does not convert to &quot; Some life is held 

 dear by,&quot; etc., or to &quot; No man holds death dear &quot; (!), but to &quot; Something (or 

 one of the things) held dear by every man is life &quot;. 



&quot; No triangle has one side equal to the other two &quot; converts to &quot; No 

 plane figure having one side equal to the other two is a triangle &quot;. 



o/&amp;gt;. cit., p. 214, 



