For as there is no matter of fact which we believe so firmly that we cannot conceive the contrary, there would be no difference between the conception as- sented to and that which is rejected, were it not for some sentiment which distinguishes the one from the other. If I see a billiard-ball moving toward another, on a smooth table, I can easily conceive it to stop upon contact.
This conception implies no contradiction; but still it feels very differently from that conception by which I represent to myself the impulse and the communication of motion from one ball to another.
Were we to attempt a definition of this sentiment, we should, perhaps, find it a very difficult, if not an impossible task; in the same manner as if we should endeavour to define the feeling of cold or passion of anger, to a creature who never had any experience of these sentiments. Belief is the true and proper name of this feeling; and no one is ever at a loss to know the meaning of that term; because every man is every moment conscious of the sentiment represented by it.
It may not, however, be improper to attempt a description of this sentiment; in hopes we may, by that means, arrive at some analogies, which may afford a more perfect explication of it.
I say, then, that belief is nothing but a more vivid, lively, forcible, firm, steady con- ception of an object, than what the imagination alone is ever able to attain.
This variety of terms, which may seem so unphilosophical, is intended only to express that act of the mind, which renders realities, or what is taken for such, more present to us than fictions, causes them to weigh more in the thought, and gives them a superior influence on the passions and imagination.
Provided we agree about the thing, it is needless to dispute about the terms.
The imagination has the command over all its ideas, and can join and mix and vary them, in all the ways possible.
It may conceive fictitious objects with all the circumstances of place and time.
It may set them, in a manner, before our eyes, in their true colours, just as they might have existed.
But as it is impossible that this faculty of imagination can ever, of itself, reach belief, it is evident that belief consists not in the peculiar nature or order of ideas, but in the manner of their conception, and in their feeling to the mind.
I confess, that it is impossible perfectly to explain this feeling or manner of conception.
We may make use of words which express something near it.
But its true and proper name, as we observed before, is belief; which is a term that every one sufficiently under- stands in common life. And in philosophy, we can go no farther than assert, that belief is something felt by the mind, which distinguishes the ideas of the judgement from the fictions of the imagination.
It gives them more weight and influence; makes them appear of greater importance; en- forces them in the mind; and renders them the governing principle of our actions.
I hear at present, for instance, a person's voice, with whom I am acquainted; and the sound comes as from the next room.
This impression of my senses immediately conveys my thought to the person, to- gether with all the surrounding objects.
I paint them out to myself as existing at present, with the same qualities and relations, of which I formerly knew them possessed.
These ideas take faster hold of my mind than ideas of an en- chanted castle. They are very different to the feeling, and have a much greater influence of every kind, either to give pleasure or pain, joy or sorrow.
Let us, then, take in the whole compass of this doctrine, and allow, that the sentiment of belief is nothing but a conception more intense and steady than what attends the mere fictions of the imagination, and that this manner of conception arises from a customary conjunction of the object with something present to the memory or senses: I believe that it will not be difficult, upon these supposi- tions, to find other operations of the mind analogous to it, and to trace up these phenomena to principles still more general.
We have already observed that nature has established connexions among particular ideas, and that no sooner one idea occurs to our thoughts than it introduces its cor- relative, and carries our attention towards it, by a gentle and insensible movement.
These principles of connexion or association we have reduced to three, namely, Resem- blance, Contiguity and Causation; which are the only bonds that unite our thoughts together, and beget that regular train of reflection or discourse, which, in a greater or less degree, takes place among all mankind.
Now here arises a question, on which the solution of the present difficulty will depend.
Does it happen, in all these relations, that, when one of the objects is presented to the senses or memory, the mind is not only carried to the conception of the correlative, but reaches a steadier and stronger conception of it than what otherwise it would have been able to attain? This seems to be the case with that belief which arises from the relation of cause and effect.
And if the case be the same with the other relations or principles of associations, this may be established as a general law, which takes place in all the operations of the mind.
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, 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 it is set before us; but when it is 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 instances of the same nature.
The dev- otees of that superstition usually plead in excuse for the mummeries, with which they are upbraided, that they feel the good effect of those external motions, and pos- tures, and actions, in enlivening their devotion and quick- ening their fervour, which otherwise would decay, 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 it is pos- sible for us to do merely by an intellectual view and contemplation. Sensible objects have always a greater in- fluence 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 resem- blance in enlivening the ideas 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. It is certain that distance dimin- ishes 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, which imitates an immediate impression.
The thinking on any object readily transports the mind to what is contiguous; but it is only the actual presence of an object, that trans- ports 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 neigh- bourhood of my friends or 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 between them; that transition alone is not able to give a superior vivacity to any of the ideas, for want of some immediate impression.
 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 reliques of saints and holy men, for the same reason, that they seek after types or 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 it is evident, that one of the best reliques, which a devotee could procure, would be the handywork of a saint; and if his cloaths and furniture are ever to be considered in this light, it is be- cause 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, by which we learn the reality of his existence.
Suppose, that the son of a friend, who had been long dead or absent, were presented to us; it is evident, that this object would instantly revive its correlative idea, and recall to our thoughts all past intimacies and familiarities, in more lively colours than they would otherwise have ap- peared to us.
This is another phaenomenon, which seems to prove the principle above mentioned. We may observe, that, in these phaenomena, the belief of the correlative object is always presupposed; without which the relation could have no effect.
The influence of the picture supposes, that we believe our friend to have once existed.
Contiguity to home can never excite our ideas of home, unless we believe that it really exists.
Now I assert, that this belief, where it reaches beyond the memory or senses, is of a similar nature, and arises from similar causes, with the transition of thought and vivacity of conception here explained.
When I throw a piece of dry wood into a fire, my mind is immediately carried to con- ceive, that it augments, not extinguishes the flame. This transition of thought from the cause to the effect proceeds not from reason. It derives its origin altogether from custom and experience.
And as it first begins from an object, present to the senses, it renders the idea or con- ception of flame more strong and lively than any loose, floating reverie of the imagination.
That idea arises im- mediately.
The thought moves instantly towards it, and conveys to it all that force of conception, which is derived from the impression present to the senses. When a sword is levelled at my breast, does not the idea of wound and pain strike me more strongly, than when a glass of wine is presented to me, even though by accident this idea should occur after the appearance of the latter object? But what is there in this whole matter to cause such a strong conception, except only a present object and a customary transition of the idea of another object, which we have been accustomed to conjoin with the former? This is the whole operation of the mind, in all our conclusions con- cerning matter of fact and existence; and it is a satisfaction to find some analogies, by which it may be explained.
The transition from a present object does in all cases give strength and solidity to the related idea.
Here, then, is a kind of pre-established harmony between the course of nature and the succession of our ideas; and though the powers and forces, by which the former is gov- erned, be wholly unknown to us; yet our thoughts and conceptions have still, we find, gone on in the same train with the other works of nature.
Custom is that principle, by which this correspondence has been effected; so neces- sary to the subsistence of our species, and the regulation of our conduct, in every circumstance and occurrence of hu- man life.
Had not the presence of an object, instantly excited the idea of those objects, commonly conjoined with it, all our knowledge must have been limited to the narrow sphere of our memory and senses; and we should never have been able to adjust means to ends, or employ our natural powers, either to the producing of good, or avoiding of evil.
Those, who delight in the discovery and contem- plation of final causes, have here ample subject to employ their wonder and admiration. I shall add, for a further confirmation of the foregoing theory, that, as this operation of the mind, by which we infer like effects from like causes, and vice versa, is so essential to the subsistence of all human creatures, it is not probable, that it could be trusted to the fallacious de- ductions of our reason, which is slow in its operations; appears not, in any degree, during the first years of infancy; and at best is, in every age and period of human life, ex- tremely liable to error and mistake.
It is more conformable to the ordinary wisdom of nature to secure so necessary an act of the mind, by some instinct or mechanical tendency, which may be infallible in its operations, may discover itself at the first appearance of life and thought, and may be independent of all the laboured deductions of the under- standing.
As nature has taught us the use of our limbs, without giving us the knowledge of the muscles and nerves, by which they are actuated; so has she implanted in us an instinct, which carries forward the thought in a corre- spondent course to that which she has established among external objects; though we are ignorant of those powers and forces, on which this regular course and succession of objects totally depends.
 Nothing is more useful than for writers, even, on moral, political, or physical subjects, to distinguish between reason and experience, and to sup- pose, that these species of argumentation are entirely different from each other.
The former are taken for the mere result of our intellectual facul- ties, which, by considering a priori the nature of things, and examining the effects, that must follow from their operation, establish particular prin- ciples of science and philosophy.
The latter are supposed to be derived entirely from sense and observation, by which we learn what has actually resulted from the operation of particular objects, and are thence able to infer, what will, for the future, result from them.
Thus, for instance, the limitations and restraints of civil government, and a legal constitution, may be defended, either from reason, which reflecting on the great frailty and corruption of human nature, teaches, that no man can safely be trusted with unlimited authority; or from experience and history, which inform us of the enormous abuses, that ambition, in every age and country, has been found to make so imprudent a confidence.
The same distinction between reason and experience is maintained in all our deliberations concerning the conduct of life; while the experienced states- man, general, physician, or merchant is trusted and followed; and the unprac- tised novice, with whatever natural talents endowed, neglected and despised.
Though it be allowed, that reason may form very plausible conjectures with regard to the consequences of such a particular conduct in such particular circumstances; it is still supposed imperfect, without the assistance of experi- ence, which is alone able to give stability and certainty to the maxims, derived from study and reflection.
But notwithstanding that this distinction be thus universally received, both in the active and speculative scenes of life, I shall not scruple to pro- nounce, that it is, at bottom, erroneous, at least, superficial.
If we examine those arguments, which, in any of the sciences above mentioned, are supposed to be mere effects of reasoning and reflection, they will be found to terminate, at last, in some general principle or, con- clusion, for which we can assign no reason but observation and experience. The only difference between them and those maxims, which are vulgarly esteemed the result of pure experience, is, that the former cannot be estab- lished without some process of thought, and some reflection on what we have observed, in order to distinguish its circumstances, and trace its con- sequences: Whereas in the latter, the experienced event is exactly and fully familiar to that which we infer as the result of any particular situation.
room for doubt or opposition.