An Essay on the Signs of Ideas. 261 
and mouth, we never have them distinctly or 
permanently, ) but merely the words which are 
the names of the original sensations. And 
from these words we reason quite as correctly 
as from real ideas, because, having formerly 
observed and compared the effects of these 
sensations upon ourselves and others, we are 
enabled to speak concerning them, without 
error; for they in truth, and not the sensa- 
tions themselves, form the general subject 
of such reasonings. 
Even of visible and audible objects, the 
ideas are not always necessary to correct 
reasoning. ‘The signs of these ideas are, for 
many purposes, quite sufficient, as was fully 
shewn in the instance of Blacklock, a poet 
of no despicable pretensions, who became 
totally blind before he was six months old. 
« Nature,” as he himselfsays, ‘ when scarce fair light 
he knew,” 
** Snatch’d heaven, earth, beauty, from his view, 
* And darkness round him reign’d,’” 
He has, however, described with much cor- 
rectness, and apparent feeling, the various 
appearances of objects. His poems contain 
innumerable instances of the appropriate use 
of words, intended to signify ideas to which 
he must have been an entire stranger. 
It is perfectly true then, as asserted by Mr. 
