OF THE CAUSES OF BELIEF.
Having thus explained the nature of belief, and shown that it consists
in a lively idea related to a present impression; let us now proceed
to examine from what principles it is derived, and what bestows the
vivacity on the idea.
I would willingly establish it as a general maxim in the science of
human nature, _that when any impression becomes present to us, it
not only transports the mind to such ideas as are related to it, but
likewise communicates to them a share of its force and vivacity_.
All the operations of the mind depend, in a great measure, on its
disposition when it performs them; and according as the spirits are
more or less elevated, and the attention more or less fixed, the action
will always have more or less vigour and vivacity. When, therefore,
any object is presented which elevates and enlivens the thought, every
action, to which the mind applies itself, will be more strong and
vivid, as long as that disposition continues. Now, 'tis evident the
continuance of the disposition depends entirely on the objects about
which the mind is employed; and that any new object naturally gives a
new direction to the spirits, and changes the disposition; as on the
contrary, when the mind fixes constantly on the same object, or passes
easily and insensibly along related objects, the disposition has a
much longer duration. Hence it happens, that when the mind is once
enlivened by a present impression, it proceeds to form a more lively
idea of the related objects, by a natural transition of the disposition
from the one to the other. The change of the objects is so easy, that
the mind is scarce sensible of it, but applies itself to the conception
of the related idea with all the force and vivacity it acquired from
the present impression.
If, in considering the nature of relation, and that facility of
transition which is essential to it, we can satisfy ourselves
concerning the reality of this phenomenon, 'tis well: but I must
confess I place my chief confidence in experience to prove so material
a principle. We may therefore observe, as the first experiment to our
present purpose, that upon the appearance of the picture of an absent
friend, our idea of him is evidently enlivened by the _resemblance_,
and that every passion, which that idea occasions, whether of joy or
sorrow, acquires new force and vigour. In producing this effect there
concur both a relation and a present impression. Where the picture
bears him no resemblance, or at least was not intended for him, it
never so much as conveys our thought to him: and where it is absent as
well as the person; though the mind may pass from the thought of the
one to that of the other; it feels its idea to be rather weakened than
enlivened by that transition. We take a pleasure in viewing the picture
of a friend, when 'tis set before us; but when 'tis removed, rather
choose to consider him directly, than by reflection in an image, which
is equally distant and obscure.
The ceremonies of the Roman Catholic religion may be considered
as experiments of the same nature. The devotees of that strange
superstition usually plead in excuse of the mummeries with which they
are up-braided, that they feel the good effect of those external
motions, and postures and actions, in enlivening their devotion, and
quickening their fervour, which otherwise would decay away, if directed
entirely to distant and immaterial objects. We shadow out the objects
of our faith, say they, in sensible types and images, and render
them more present to us by the immediate presence of these types,
than 'tis possible for us to do, merely by an intellectual view and
contemplation. Sensible objects have always a greater influence on the
fancy than any other; and this influence they readily convey to those
ideas to which they are related, and which they resemble. I shall only
infer from these practices, and this reasoning, that the effect of
resemblance in enlivening the idea is very common; and as in every case
a resemblance and a present impression must concur, we are abundantly
supplied with experiments to prove the reality of the foregoing
principle.
We may add force to these experiments by others of a different
kind, in considering the effects of _contiguity_, as well as of
_resemblance_.'Tis certain that distance diminishes the force of
every idea; and that, upon our approach to any object, though it does
not discover itself to our senses, it operates upon the mind with an
influence that imitates an immediate impression. The thinking on any
object readily transports the mind to what is contiguous; but 'tis
only the actual presence of an object, that transports it with a
superior vivacity. When I am a few miles from home, whatever relates
to it touches me more nearly than when I am two hundred leagues
distant; though even at that distance the reflecting on any thing in
the neighbourhood of my friends and family naturally produces an idea
of them. But as in this latter case, both the objects of the mind are
ideas; notwithstanding there is an easy transition betwixt them; that
transition alone is not able to give a superior vivacity to any of the
ideas, for want of some immediate impression.[7]
No one can doubt but causation has the same influence as the other
two relations of resemblance and contiguity. Superstitious people are
fond of the relicks of saints and holy men, for the same reason that
they seek after types and images, in order to enliven their devotion,
and give them a more intimate and strong conception of those exemplary
lives, which they desire to imitate. Now, 'tis evident one of the best
relicks a devotee could procure would be the handy-work of a saint;
and if his clothes and furniture are ever to be considered in this
light, 'tis because they were once at his disposal, and were moved
and affected by him; in which respect they are to be considered as
imperfect effects, and as connected with him by a shorter chain of
consequences than any of those, from which we learn the reality of his
existence. This phenomenon clearly proves, that a present impression
with a relation of causation may enliven any idea, and consequently
produce belief or assent, according to the precedent definition of it.
But why need we seek for other arguments to prove, that a present
impression with a relation or transition of the fancy may enliven any
idea, when this very instance of our reasonings from cause and effect
will alone suffice to that purpose? 'Tis certain we must have an idea
of every matter of fact which we believe. 'Tis certain that this idea
arises only from a relation to a present impression. 'Tis certain that
the belief superadds nothing to the idea, but only changes our manner
of conceiving it, and renders it more strong and lively. The present
conclusion concerning the influence of relation is the immediate
consequence of all these steps; and every step appears to me sure and
infallible. There enters nothing into this operation of the mind but
a present impression, a lively idea, and a relation or association in
the fancy betwixt the impression and idea; so that there can be no
suspicion of mistake.
In order to put this whole affair in a fuller light, let us consider
it as a question in natural philosophy, which we must determine by
experience and observation. I suppose there is an object presented,
from which I draw a certain conclusion, and form to myself ideas, which
I am said to believe or assent to. Here 'tis evident, that however that
object, which is present to my senses, and that other, whose existence
I infer by reasoning, may be thought to influence each other by their
particular powers or qualities; yet as the phenomenon of belief, which
we at present examine, is merely internal, these powers and qualities
being entirely unknown, can have no hand in producing it. 'Tis the
present impression which is to be considered as the true and real cause
of the idea, and of the belief which attends it. We must therefore
endeavour to discover, by experiments, the particular qualities by
which 'tis enabled to produce so extraordinary an effect.
First then I observe, that the present impression has not this effect
by its own proper power and efficacy, and, when considered alone
as a single perception, limited to the present moment. I find that
an impression, from which, on its first appearance, I can draw no
conclusion, may afterwards become the foundation of belief, when I have
had experience of its usual consequences. We must in every case have
observed the same impression in past instances, and have found it to
be constantly conjoined with some other impression. This is confirmed
by such a multitude of experiments, that it admits not of the smallest
doubt.
From a second observation I conclude, that the belief which attends the
present impression, and is produced by a number of past impressions and
conjunctions; that this belief, I say, arises immediately, without any
new operation of the reason or imagination. Of this I can be certain,
because I never am conscious of any such operation, and find nothing
in the subject on which it can be founded. Now, as we call every
thing _custom_ which proceeds from a past repetition, without any new
reasoning or conclusion, we may establish it as a certain truth, that
all the belief, which follows upon any present impression, is derived
solely from that origin. When we are accustomed to see two impressions
conjoined together, the appearance or idea of the one immediately
carries us to the idea of the other.
Being fully satisfied on this head, I make a third set of experiments,
in order to know whether any thing be requisite, beside the customary
transition, towards the production of this phenomenon of belief. I
therefore change the first impression into an idea; and observe, that
though the customary transition to the correlative idea still remains,
yet there is in reality no belief nor persuasion. A present impression,
then, is absolutely requisite to this whole operation; and when after
this I compare an impression with an idea, and find that their only
difference consists in their different degrees of force and vivacity,
I conclude upon the whole, that belief is a more vivid and intense
conception of an idea, proceeding from its relation to a present
impression.
Thus, all probable reasoning is nothing but a species of sensation.
'Tis not solely in poetry and music we must follow our taste and
sentiment, but likewise in philosophy. When I am convinced of any
principle, 'tis only an idea which strikes more strongly upon me. When
I give the preference to one set of arguments above another, I do
nothing but decide from my feeling concerning the superiority of their
influence. Objects have no discoverable connexion together; nor is it
from any other principle but custom operating upon the imagination,
that we can draw any inference from the appearance of one to the
existence of another.
'Twill here be worth our observation, that the past experience, on
which all our judgments concerning cause and effect depend, may operate
on our mind in such an insensible manner as never to be taken notice
of, and may even in some measure be unknown to us. A person, who stops
short in his journey upon meeting a river in his way, foresees the
consequences of his proceeding forward; and his knowledge of these
consequences is conveyed to him by past experience, which informs him
of such certain conjunctions of causes and effects. But can we think,
that on this occasion he reflects on any past experience, and calls
to remembrance instances that he has seen or heard of, in order to
discover the effects of water on animal bodies? No, surely; this is not
the method, in which he proceeds in his reasoning. The idea of sinking
is so closely connected with that of water, and the idea of suffocating
with that of sinking, that the mind makes the transition without the
assistance of the memory. The custom operates before we have time for
reflection. The objects seem so inseparable, that we interpose not
a moment's delay in passing from the one or the other. But as this
transition proceeds from experience, and not from any primary connexion
betwixt the ideas, we must necessarily acknowledge, that experience may
produce a belief and a judgment of causes and effects by a separate
operation, and without being once thought of. This removes all pretext,
if there yet remains any, for asserting that the mind is convinced
by reasoning of that principle, _that instances of which we have no
experience, must necessarily resemble those of which we have_. For we
here find, that the understanding or imagination can draw inferences
from past experience, without reflecting on it; much more without
forming any principle concerning it, or reasoning upon that principle.
In general we may observe, that in all the most established and uniform
conjunctions of causes and effects, such as those of gravity, impulse,
solidity, &c. the mind never carries its view expressly to consider
any past experience: though in other associations of objects, which
are more rare and unusual, it may assist the custom and transition
of ideas by this reflection. Nay we find in some cases, that the
reflection produces the belief without the custom; or, more properly
speaking, that the reflection produces the custom in an _oblique_ and
_artificial_ manner. I explain myself. 'Tis certain, that not only in
philosophy, but even in common life, we may attain the knowledge of a
particular cause merely by one experiment, provided it be made with
judgment, and after a careful removal of all foreign and superfluous
circumstances. Now, as after one experiment of this kind, the mind,
upon the appearance either of the cause or the effect, can draw an
inference concerning the existence of its correlative, and as a habit
can never be acquired merely by one instance, it may be thought that
belief cannot in this case be esteemed the effect of custom. But this
difficulty will vanish, if we consider, that, though we are here
supposed to have had only one experiment of a particular effect,
yet we have many millions to convince us of this principle, _that
like objects, placed in like circumstances, will always produce like
effects_; and as this principle has established itself by a sufficient
custom, it bestows an evidence and firmness on any opinion to which it
can be applied. The connexion of the ideas is not habitual after one
experiment; but this connexion is comprehended under another principle
that is habitual; which brings us back to our hypothesis. In all cases
we transfer our experience to instances of which we have no experience,
either _expressly_ or _tacitly_, either _directly_ or _indirectly_.
I must not conclude this subject without observing, that 'tis very
difficult to talk of the operations of the mind with perfect propriety
and exactness; because common language has seldom made any very nice
distinctions among them, but has generally called by the same term
all such as nearly resemble each other. And as this is a source
almost inevitable of obscurity and confusion in the author, so it may
frequently give rise to doubts and objections in the reader, which
otherwise he would never have dreamed of. Thus, my general position,
that an opinion or belief is _nothing but a strong and lively idea
derived from a present impression related to it_, may be liable to the
following objection, by reason of a little ambiguity in those words
_strong_ and _lively_. It may be said, that not only an impression
may give rise to reasoning, but that an idea may also have the same
influence; especially upon my principle, _that all our ideas are
derived from correspondent impressions_. For, suppose I form at present
an idea, of which I have forgot the correspondent impression, I am able
to conclude, from this idea, that such an impression did once exist;
and as this conclusion is attended with belief, it may be asked, from
whence are the qualities of force and vivacity derived which constitute
this belief? And to this I answer very readily, _from the present
idea_. For as this idea is not here considered as the representation
of any absent object, but as a real perception in the mind, of which
we are intimately conscious, it must be able to bestow, on whatever
is related to it, the same quality, call it _firmness, or solidity,
or force, or vivacity_, with which the mind reflects upon it, and is
assured of its present existence. The idea here supplies the place of
an impression, and is entirely the same, so far as regards our present
purpose.
Upon the same principles we need not be surprised to hear of the
remembrance of an idea; that is, of the idea of an idea, and of
its force and vivacity superior to the loose conceptions of the
imagination. In thinking of our past thoughts we not only delineate out
the objects of which we were thinking, but also conceive the action of
the mind in the meditation, that certain _je-ne-scai-quoi_, of which
'tis impossible to give any definition or description, but which every
one sufficiently understands. When the memory offers an idea of this,
and represents it as past, 'tis easily conceived how that idea may have
more vigour and firmness than when we think of a past thought of which
we have no remembrance.
After this, any one will understand how we may form the idea of an
impression and of an idea, and how we may believe the existence of an
impression and of an idea.
[7] Naturane nobis, inquit, datum dicam, an errore quodam, ut, cum
ea loca videamus, in quibus memoria dignos viros acceperimus multum
esse versatos, magis moveamur, quam siquando eorum ipsorum aut facta
audiamus, aut scriptum aliquod legamus? velut ego nunc moveor. Venit
enim mihi Platonis in mentem: quem accipimus prinum hîc disputare
solitum: cujus etiam illi hortuli propinqui non memoriam solûm
mihi afferunt, sed ipsum videntur in conspectu meo hic ponere. Hîc
Speusippus, hic Xenocrates, hic ejus auditor Polemo; cujus ipsa illa
sessio fuit, quam videamus. Equidem etiam curiam nostram, hostiliam
dico, non hanc novam, quæ mihi minor esse videtur postquam est major,
solebam intuens Scipionem, Catonem, Lælium, nostrum vero in primis avum
cogitare. Tanta vis admonitionis inest in locis; ut non sine causa ex
his memoriæ ducta sit diciplina.--_Cicero de Finibus, lib. 5._