Since, therefore, the imagination can represent all the same objects that
the memory can offer to us, and since those faculties are only
distinguished by the different feeling of the ideas they present, it may
be proper to consider what is the nature of that feeling. And here I
believe every one will readily agree with me, that the ideas of the
memory are more strong and lively than those of the fancy.

A painter, who intended to represent a passion or emotion of any kind,
would endeavour to get a sight of a person actuated by a like emotion, in
order to enliven his ideas, and give them a force and vivacity superior
to what is found in those, which are mere fictions of the imagination.
The more recent this memory is, the clearer is the idea; and when after a
long interval he would return to the contemplation of his object, he
always finds its idea to be much decayed, if not wholly obliterated. We
are frequently in doubt concerning the ideas of the memory, as they
become very weak and feeble; and are at a loss to determine whether any
image proceeds from the fancy or the memory, when it is not drawn in such
lively colours as distinguish that latter faculty. I think, I remember
such an event, says one; but am not sure. A long tract of time has almost
worn it out of my memory, and leaves me uncertain whether or not it be
the pure offspring of my fancy.

And as an idea of the memory, by losing its force and vivacity, may
degenerate to such a degree, as to be taken for an idea of the
imagination; so on the other hand an idea of the imagination may acquire
such a force and vivacity, as to pass for an idea of the memory, and
counterfeit its effects on the belief and judgment. This is noted in the
case of liars; who by the frequent repetition of their lies, come at last
to believe and remember them, as realities; custom and habit having in
this case, as in many others, the same influence on the mind as nature,