mind, or are deriv'd from the author of our being...

Nor is such a question
any way material to our present purpose. We may draw inferences from
the coherence of our perceptions, whether they be true or false; whether
they represent nature justly, or be mere illusions of the senses.
When we search for the characteristic, which distinguishes the memory
from the imagination, we must immediately perceive, that it cannot lie in
the simple ideas it presents to us; since both these faculties borrow their
simple ideas from the impressions, and can never go beyond these
original perceptions. These faculties are as little distinguished from each
other by the arrangement of their complex ideas. For tho' it be a peculiar
property of the memory to preserve the original order and position of its
ideas, while the imagination transposes and changes them, as it pleases;
yet this difference is not sufficient to distinguish them in their operation,
or make us know the one from the other; it being impossible to recal the
past impressions, in order to compare them with our present ideas, and
see whether their arrangement be exactly similar. Since therefore the
memory, is known, neither by the order of its complex ideas, nor the
nature of its simple ones; it follows, that the difference betwixt it and the
imagination lies in its superior force and vivacity. A man may indulge his
fancy in feigning any past scene of adventures; nor wou'd there be any
possibility of distinguishing this from a remembrance of a like kind,
were not the ideas of the imagination fainter and more obscure.


[The following two paragraphs are inserted from the appendix.]
It frequently happens, that when two men have been engag'd in any
scene of action, the one shall remember it much better than the other,
and shall have all the difficulty in the world to make his companion
recollect it. He runs over several circumstances in vain; mentions the
time, the place, the company, what was said, what was done on all sides;
till at last he hits on some lucky circumstance, that revives the whole, and
gives his friend a perfect memory of every thing. Here the person that
forgets receives at first all the ideas from the discourse of the other, with
the same circumstances of time and place; tho' he considers them as
mere fictions of the imagination. But as soon as the circumstance is
mention'd, that touches the memory, the very same ideas now appear in
a new light, and have, in a manner, a different feeling from what they
had before. Without any other alteration, beside that of the feeling, they
become immediately ideas of the memory, and are assented to.
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,
wou'd 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 wou'd return to the contemplation of his object, he always
finds its idea to be much decay'd, 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,
and infixing the idea with equal force and vigour.
Thus it appears, that the belief or assent, which always attends the
memory and senses, is nothing but the vivacity of those perceptions they
present; and that this alone distinguishes them from the imagination. To
believe is in this case to feel an immediate impression of the senses, or a
repetition of that impression in the memory. 'Tis merely the force and
liveliness of the perception, which constitutes the first act of the
judgment, and lays the foundation of that reasoning, which we build
upon it, when we trace the relation of cause and effect.


SECT. VI.
Of the Inference from the Impression to the Idea.
'Tis easy to observe, that in tracing this relation, the inference we draw
from cause to effect, is not deriv'd merely from a survey of these
particular objects, and from such a penetration into their essences as
may discover the dependance of the one upon the other. There is no
object., which implies the existence of any other if we consider these
objects in themselves, and never look beyond the ideas which we form of
them. Such an inference wou'd amount to knowledge, and wou'd imply
the absolute contradiction and impossibility of conceiving any thing
different. But as all distinct ideas are separable, 'tis evident there can be
no impossibility of that kind. When we pass from a present impression
to the idea of any object, we might possibly have separated the idea from
the impression, and have substituted any other idea in its room.
'Tis therefore by EXPERIENCE only, that we can infer the existence of
one object from that of another. The nature of experience is this. We
remember to have had frequent instances of the existence of one species
of objects; and also remember, that the individuals of another species of
objects have always attended them, and have existed in a regular order of
contiguity- and succession with regard to them. Thus we remember, to
have seen that species of object we call flame, and to have felt that species
of sensation we call heat. We likewise call to mind their constant
conjunction in all past instances. Without any farther ceremony, we call
the one cause and the other effect, and infer the existence of the one