An Essay on the Signs of Ideas, 245 
On such occasions, we know that the ob- 
jects themselves are absent, partly by the 
comparative faintness of the feelings, and 
partly by the circumstance, that no corres- 
ponding feelings are excited in the other or- 
gans of sense. Thus, if I have the idea of 
arose, I know that it is not an original sen- 
sation excited by the actual presence of a rose, 
because, if it were, in addition to the sensa- 
tion of colour and figure by the eye, I should 
have the sensation of odour by the nose, and, 
if I chose, the sensations of smoothness, figure, 
magnitude, &c. by the skin. 
But the comparative faintness is the prin- 
cipal thing that distinguishes an idea ;—for 
sometimes ideas are so strong as to be mista- 
ken for original sensations ; and when, in 
any person, this mistake is frequent or per- 
manent, we say that such person is insane. 
In all cases then, except those of insanity, 
ideas or remembered sensations are much more 
feeble and indistinct than the original sensa- 
tions, and commonly possess the less strength 
and clearness, the greater the period of time 
that has intervened since the application of the 
agents from which they have arisen ; and with 
regard to this, itis an obvious fact, that ideas 
of the objects of some senses, arise with much 
