OF THE IMPRESSIONS OF THE SENSES AND MEMORY.
In this kind of reasoning, then, from causation, we employ materials,
which are of a mixed and heterogeneous nature, and which, however
connected, are yet essentially different from each other. All our
arguments concerning causes and effects consist both of an impression
of the memory or senses, and of the idea of that existence, which
produces the object of the impression, or is produced by it. Here,
therefore, we have three things to explain, viz. _first_, the original
impression. _Secondly_, the transition to the idea of the connected
cause or effect. _Thirdly_, the nature and qualities of that idea.
As to those _impressions_, which arise from the _senses_, their
ultimate cause is, in my opinion, perfectly inexplicable by human
reason, and 'twill always be impossible to decide with certainty,
whether they arise immediately from the object, or are produced by
the creative power of the mind, or are derived 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, though 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 would 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.
It frequently happens, that when two men have been engaged 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;
though he considers them as mere fictions of the imagination. But as
soon as the circumstance is mentioned 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,
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 Of hand, an idea of the imagination may
acquire such a and 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.