254 An Essay on the Signs of Ideas. 
kinds, it naturally came to signify any indivi- 
dual of that kind. Hence the origin. of ge- 
neral terms, which, by a strange perversion, 
have been stated to stand for general ideas ; 
whereas a general idea cannot possibly have 
any existence: all ideas are, and must ‘be, 
particular. ee 
Let us then briefly examine in oe al 
such general terms are to be considered as the 
signsof ideas. Imagine a speaker addressing 
a numerous assembly, and using the word tri- 
angle, with the intention of elucidating some 
of ‘its properties. I suppose him to use no di- 
agram, but to be proceeding altogether men- 
tally. Let him be demonstrating: the twen- 
tieth proposition of Euclid, that inevery tri- 
angle any two sides, however taken, are to- 
gether greater than the remaining side. Now, 
I assert that the probability is almost infinite, 
that no. two of his hearers have exactly the 
same feeling or image raised by the teacher, 
when using the word triangle. One will see, 
in his mind’s eye, an equilateral triangle, ano- 
ther an isosceles, athird a scalenum; one may 
conceive a right-angled, another an obtuse-an- 
gled, and another an acute-angled triangle. 
With regard to size, there will probably be a 
still greater variationintheimages. Neither 
is it necessary that the hearers should present 
