BLUE and GREEN are different simple ideas, but are more resembling than BLUE and SCARLET; tho their perfect simplicity excludes all possibility of separation or distinction.

It is the same case with particular sounds, and tastes and smells.

These admit of infinite resemblances upon the general appearance and comparison, without having any common circumstance the same.

And of this we may be certain, even from the very abstract terms SIMPLE IDEA.

They comprehend all simple ideas under them.