800 Mr DE morgan, ON THE SYLLOGISM, No. Ill, 



which is all used, but all is not enough : there is no word which signifies a deficiency arising, 

 it may be, from a sufficiency being bestowed elsewhere. In the language I use, X is a defi- 

 cient of Y, if there be any part of Y which is not X. 



On coeacternal and copartient, I need say nothing. The word complement means either 

 contrary, or supercontrary (containing all the contrary and also copartient). 



As to coinadequate, I may observe that if the earlier logicians had studied the relations 

 of exclusion with any amount of sustained attention, we should have been provided with names 

 to express many relations which are perhaps not so much, certainly not so clearly, in thought 

 as they ought to be, chiefly for want of names. The notion of combination is confined to 

 what is positive: things may conspire to produce, cause, be sufficient, &c., but they do not, in 

 usual idiom, conspire to be insufficient. When it is denied that the contraries of X and Y 

 are coexclusive of each other, so that some things are neither Xs nor Ys, that is, X and Y do 

 not together fill the universe, we see that they are not together adequate, conspire to be in- 

 adequate, are coinadequate. This may introduce the word, but it was not of my making, nor 

 formed by such a deduction. I asked a friend who was likely to give an answer, "What, 

 supposing A and B to be areas not together large enough to make C, he would say A and B 

 were to one another in reference to this joint insufficiency : his almost immediate answer was, 

 Coinadequate. 



2. Terminal ambiguity, metaphysical view. Not being here restricted by usage but, 

 on the contrary, supported by common idiom, I make the distinction of universal and parti- 

 cular to be merely that of assertion and denial of completeness. Accordingly, X is either an 

 essential or an inessential of Y ; either a dependent or an independent ; either a repugnant or 

 an irrepugnant; eitlier an alternative or an inalternative. The four last words may have the 

 sign of convertible relation, Co-, prefixed when wanted. 



Essential arid Dependent, Compare these words with genus and species, and the habits 

 of thought of the world at large are well illustrated. The common substantive is of the 

 mathematical type ; the common adjective of the metaphysical. The common proposition 

 being physical, the world has a good hold on the substantive species and the adjective essential : 

 but it knows much less of the substantive genus, or of the adjective dependent, as here used. 

 Nevertheless, the word dependent is common enough : as in. Cleanliness is essential to comfort; 

 comfort depends upon cleanliness. The logician has only the abacus, ' All comfortable is clean.' 

 On the remaining words there is no especial remark to make, except the one which this very 

 dismissal suggests : namely, that it is easy to pick out of common usage a moderately good set 

 of logico-metaphysical words of relation, while as good a set of logico-mathematical words does 

 not exist in the common dictionary. I believe that this phenomenon does not give much coun- 

 tenance to common logic as an exponent of actual thought, though it bears testimony to the 

 science as, in one particular, an improver of it. 



3. Terminal precision, mathematical view. The phrases used are those which are 

 found in my Formal Logic : and need no especial remark here. The only addition is the 

 distinction of extension and intension : thus the subidentical in extension is the superidentical 

 in intension, &c. This distinction is so easily made that I have not thought it worth while 

 to tabulate it. 



