How men in sound memory distinguish the ideas remembered, from sensations remembered, and know that the one is not the other, seems to be accounted for by the difference of the things themselves. A sensation is different from an idea, only because it is felt to be different; and being felt to be different, and known to be different, are not two things, but one and the same thing. I have a sensation; I have an idea: if these two are distinguishable in the having, it is likely that the copy of the sensation should be distinguishable from the revival of the idea, when they are both brought up by association; just as when I {335} have two distinguishable sensations, one, for example, of red, and another of black, the copies of them, when brought up by association, are distinguishable. Besides, the accompaniments of a sensation are always generically different from those of an idea; of course, the associations are generically different. The accompaniments of a sensation, are all the simultaneous objects of sensation, together with all those which, to a certain extent, both preceded and followed it. The accompaniments of an idea are not the simultaneous objects of sensation, but other ideas; namely, the neighbouring parts, antecedent and consequent, of the mental train. A sensation, therefore, called up by association, and an idea called up by association, are distinguished both by the difference of the two feelings, and the difference of the associated circumstances. It is observable, that the idea of a sensation called up by association, and recognised as the idea of a sensation, is of course a remembrance. The recognition consists in that highly complex idea, consisting of three principal ingredients: 1, the point of consciousness called the remembering self; 2, the point of consciousness called the percipient self; 3, the successive states of consciousness which filled up the interval, between these two points. An _idea_ called up by association is not necessarily a remembrance; it is only a remembrance when recognised as having been an idea before. And it is recognised as having been an idea before, by the association of that idea, which connects the self of the present moment with the self of the past moment, the remembering self with the conceiving self: in other {336} words, the complex idea is made up of those two selfs and the intermediate states of consciousness.