An Essay on the Signs of Ideas. 259 
highest kind. The highest authority, of 
course, is the law of God, and next to that, 
the law of the community in which we live. 
Let us now proceed to the consideration of 
words which in nowise representideas. These 
forma very extensive class: ‘They are of three 
kinds: first, words which from the nature of 
things are altogether devoid of archetypes; 
secondly, words standing not for ideas, but, 
either for such simple and original sen- 
sations, as are never ideally renewed, or for 
sensations of emotion, which are never call- 
ed up except by the original cause, and can- 
not therefore in any case be called ideas ; 
thirdly, words standing for causes whose 
effects alone we witness, and thence judge the 
existence of the cause, without being able to 
form any conception of it; and fourthly, 
words which at present have no ideas attach- 
edto them, although the contrary might have 
been the case when they were originally 
brought into use. 
Of the first kind are Bick terms point and 
line,’ as used by mathematicians. When we 
hear the definition of a mathematical point, is 
any idea raised in the mind? Certainly not ; 
or at least none that corresponds with the de- 
finition. It is necessarily the same with the 
mathematical definition of a line, ‘The use 
