PART III. (continued 2)

As resemblance, when conjoined with causation, fortifies our reasonings, so the want of it in any very great degree is able almost entirely to destroy them. Of this there is a remarkable instance in the universal carelessness and stupidity of men with regard to a future state, where they show as obstinate an incredulity, as they do a blind credulity on other occasions. There is not indeed a more ample matter of wonder to the studious, and of regret to the pious man, than to observe the negligence of the bulk of mankind concerning their approaching condition; and 'tis with reason, that many eminent theologians have not scrupled to affirm, that though the vulgar have no formal principles of infidelity, yet they are really infidels in their hearts, and have nothing like what we can call a belief of the eternal duration of their souls. For let us consider on the one hand what divines have displayed with such eloquence concerning the importance of eternity; and at the same time reflect, that though in matters of rhetoric we ought to lay our account with some exaggeration, we must in this case allow, that the strongest figures are infinitely inferior to the subject: and after this, let us view on the other hand the prodigious security of men in this particular: I ask, if these people really believe what is inculcated on them, and what they pretend to affirm; and the answer is obviously in the negative. As belief is an act of the mind arising from custom, 'tis not strange the want of resemblance should overthrow what custom has established, and diminish the force of the idea, as much as that latter principle increases it. A future state is so far removed from our comprehension, and we have so obscure an idea of the manner in which we shall exist after the dissolution of the body, that all the reasons we can invent, however strong in themselves, and however much assisted by education, are never able with slow imaginations to surmount this difficulty, or bestow a sufficient authority and force on the idea. I rather choose to ascribe this incredulity to the faint idea we form of our future condition, derived from its want of resemblance to the present life, than to that derived from its remoteness. For I observe, that men are every where concerned about what may happen after their death, provided it regard this world; and that there are few to whom their name, their family, their friends, and their country are in any period of time entirely indifferent.

And indeed the want of resemblance in this case so entirely destroys belief, that except those few who, upon cool reflection on the importance of the subject, have taken care by repeated meditation to imprint in their minds the arguments for a future state, there scarce are any who believe the immortality of the soul with a true and established judgment; such as is derived from the testimony of travellers and historians. This appears very conspicuously wherever men have occasion to compare the pleasures and pains, the rewards and punishments of this life with those of a future; even though the case does not concern themselves, and there is no violent passion to disturb their judgment. The Roman Catholics are certainly the most zealous of any sect in the Christian world; and yet you'll find few among the more sensible part of that communion who do not blame the Gunpowder Treason, and the massacre of St Bartholomew, as cruel and barbarous, though projected or executed against those very people, whom without any scruple they condemn to eternal and infinite punishments. All we can say in excuse for this inconsistency is, that they really do not believe what they affirm concerning a future state; nor is there any better proof of it than the very inconsistency.

We may add to this a remark, that in matters of religion men take a pleasure in being terrified, and that no preachers are so popular as those who excite the most dismal and gloomy passions. In the common affairs of life, where we feel and are with the solidity of the subject, nothing can be more disagreeable than fear and terror; and 'tis only in dramatic performances and in religious discourses that they ever give pleasure. In these latter cases the imagination reposes itself indolently on the idea; and the passion being softened by the want of belief in the subject, has no more than the agreeable effect of enlivening the mind and fixing the attention.

The present hypothesis will receive additional confirmation, if we examine the effects of other kinds of custom, as well as of other relations. To understand this we must consider that custom, to which I attribute all belief and reasoning, may operate upon the mind in invigorating an idea after two several ways. For supposing that, in all past experience, we have found two objects to have been always conjoined together, 'tis evident, that upon the appearance of one of these objects in an impression, we must, from custom, make an easy transition to the idea of that object, which usually attends it; and by means of the present impression and easy transition must conceive that idea in a stronger and more lively manner than we do any loose floating image of the fancy. But let us next suppose, that a mere idea alone, without any of this curious and almost artificial preparation, should frequently make its appearance in the mind, this idea must, by degrees, acquire a facility and force; and both by its firm hold and easy introduction distinguish itself from any new and unusual idea. This is the only particular in which these two kinds of custom agree; and if it appear that their effects on the judgment are similar and proportionable, we may certainly conclude, that the foregoing explication of that faculty is satisfactory. But can we doubt of this agreement in their influence on the judgment, when we consider the nature and effects of education?

All those opinions and notions of things, to which we have been accustomed from our infancy, take such deep root, that 'tis impossible for us, by all the powers of reason and experience, to eradicate them; and this habit not only approaches in its influence, but even on many occasions prevails over that which arises from the constant and inseparable union of causes and effects. Here we must not be contented with saying, that the vividness of the idea produces the belief: we must maintain that they are individually the same. The frequent repetition of any idea infixes it in the imagination; but could never possibly of itself produce belief, if that act of the mind was, by the original constitution of our natures, annexed only to a reasoning and comparison of ideas. Custom may lead us into some false comparison of ideas. This is the utmost effect we can conceive of it; but 'tis certain it could never supply the place of that comparison, nor produce any act of the mind which naturally belonged to that principle.

A person that has lost a leg or an arm by amputation endeavours for a long time afterwards to serve himself with them. After the death of any one, 'tis a common remark of the whole family, but especially the servants, that they can scarce believe him to be dead, but still imagine him to be in his chamber or in any other place, where they were accustomed to find him. I have often heard in conversation, after talking of a person that is any way celebrated, that one, who has no acquaintance with him, will say, I have never seen such a one, but almost fancy I have, so often have I heard talk of him. All these are parallel instances.

If we consider this argument from education in a proper light, 'twill appear very convincing; and the more so, that 'tis founded on one of the most common phenomena that is any where to be met with. I am persuaded that, upon examination, we shall find more than one half of those opinions that prevail among mankind to be owing to education, and that the principles which are thus implicitly embraced, overbalance those, which are owing either to abstract reasoning or experience. As liars, by the frequent repetition of their lies, come at last to remember them; so the judgment, or rather the imagination, by the like means, may have ideas so strongly imprinted on it, and conceive them in so full a light, that they may operate upon the mind in the same manner with those which the senses, memory, or reason present to us. But as education is an artificial and not a natural cause, and as its maxims are frequently contrary to reason, and even to themselves in different times and places, it is never upon that account recognised by philosophers; though in reality it be built almost on the same foundation of custom and repetition as our reasonings from causes and effects.[8]

SECTION X.

OF THE INFLUENCE OF BELIEF.

But though education be disclaimed by philosophy, as a fallacious ground of assent to any opinion, it prevails nevertheless in the world, and is the cause why all systems are apt to be rejected at first as new and unusual. This, perhaps, will be the fate of what I have here advanced concerning belief; and though the proofs I have produced appear to me perfectly conclusive, I expect not to make many proselytes to my opinion. Men will scarce ever be persuaded, that effects of such consequence can flow from principles which are seemingly so inconsiderable, and that the far greatest part of our reasonings, with all our actions and passions, can be derived from nothing but custom and habit. To obviate this objection, I shall here anticipate a little what would more properly fall under our consideration afterwards, when we come to treat of the Passions and the Sense of Beauty.

There is implanted in the human mind a perception of pain and pleasure, as the chief spring and moving principle of all its actions. But pain and pleasure have two ways of making their appearance in the mind; of which the one has effects very different from the other. They may either appear an impression to the actual feeling, or only in idea, as at present when I mention them. 'Tis evident the influence of these upon our actions is far from being equal. Impressions always actuate the soul, and that in the highest degree; but 'tis not every idea which has the same effect. Nature has proceeded with caution in this case, and seems to have carefully avoided the inconveniences of two extremes. Did impressions alone influence the will, we should every moment of our lives be subject to the greatest calamities; because, though we foresaw their approach, we should not be provided by nature with any principle of action, which might impel us to avoid them. On the other hand, did every idea influence our actions, our condition would not be much mended. For such is the unsteadiness and activity of thought, that the images of every thing, especially of goods and evils, are always wandering in the mind; and were it moved by every idle conception of this kind, it would never enjoy a moment's peace and tranquillity.

Nature has therefore chosen a medium, and has neither bestowed on every idea of good and evil the power of actuating the will, nor yet has entirely excluded them from this influence. Though an idle fiction has no efficacy, yet we find by experience, that the ideas of those objects, which we believe either are or will be existent, produce in a lesser degree the same effect with those impressions, which are immediately present to the senses and perception. The effect then of belief is to raise up a simple idea to an equality with our impressions, and bestow on it a like influence on the passions. This effect it can only have by making an idea approach an impression in force and vivacity. For as the different degrees of force make all the original difference betwixt an impression and an idea, they must of consequence be the source of all the differences in the effects of these perceptions, and their removal, in whole or in part, the cause of every new resemblance they acquire. Wherever we can make an idea approach the impressions in force and vivacity, it will likewise imitate them in its influence on the mind; and vice versa, where it imitates them in that influence, as in the present case, this must proceed from its approaching them in force and vivacity. Belief, therefore, since it causes an idea to imitate the effects of the impressions, must make it resemble them in these qualities, and is nothing but a more vivid and intense conception of any idea. This then may both serve as an additional argument for the present system, and may give us a notion after what manner our reasonings from causation are able to operate on the will and passions.

As belief is almost absolutely requisite to the exciting our passions, so the passions, in their turn, are very favourable to belief; and not only such facts as convey agreeable emotions, but very often such as give pain, do upon that account become more readily the objects of faith and opinion. A coward, whose fears are easily awakened, readily assents to every account of danger he meets with; as a person of a sorrowful and melancholy disposition is very credulous of every thing that nourishes his prevailing passion. When any affecting object is presented, it gives the alarm, and excites immediately a degree of its proper passion; especially in persons who are naturally inclined to that passion. This emotion passes by an easy transition to the imagination; and, diffusing itself over our idea of the affecting object, makes us form that idea with greater force and vivacity, and consequently assent to it, according to the precedent system. Admiration and surprise have the same effect as the other passions; and accordingly we may observe, that among the vulgar, quacks and projectors meet with a more easy faith upon account of their magnificent pretensions, than if they kept themselves within the bounds of moderation. The first astonishment, which naturally attends their miraculous relations, spreads itself over the whole soul, and so vivifies and enlivens the idea, that it resembles the inferences we draw from experience. This is a mystery, with which we may be already a little acquainted, and which we shall have further occasion to be let into in the progress of this Treatise.

After this account of the influence of belief on the passions, we shall find less difficulty in explaining its effects on the imagination, however extraordinary they may appear. 'Tis certain we cannot take pleasure in any discourse, where our judgment gives no assent to those images which are presented to our fancy. The conversation of those, who have acquired a habit of lying, though in affairs of no moment, never gives any satisfaction; and that because those ideas they present to us, not being attended with belief, make no impression upon the mind. Poets themselves, though liars by profession, always endeavour to give an air of truth to their fictions; and where that is totally neglected, their performances, however ingenious, will never be able to afford much pleasure. In short, we may observe, that even when ideas have no manner of influence on the will and passions, truth and reality are still requisite, in order to make them entertaining to the imagination.

But if we compare together all the phenomena that occur on this head, we shall find, that truth, however necessary it may seem in all works of genius, has no other effect than to procure an easy reception for the ideas, and to make the mind acquiesce in them with satisfaction, or at least without reluctance. But as this is an effect, which may easily be supposed to flow from that solidity and force, which, according to my system, attend those ideas that are established by reasonings from causation; it follows, that all the influence of belief upon the fancy may be explained from that system. Accordingly we may observe, that wherever that influence arises from any other principles beside truth or reality, they supply its place, and give an equal entertainment to the imagination. Poets have formed what they call a poetical system of things, which, though it be believed neither by themselves nor readers, is commonly esteemed a sufficient foundation for any fiction. We have been so much accustomed to the names of Mars, Jupiter, Venus, that in the same manner as education infixes any opinion, the constant repetition of these ideas makes them enter into the mind with facility, and prevail upon the fancy, without influencing the judgment. In like manner tragedians always borrow their fable, or at least the names of their principal actors, from some known passage in history; and that not in order to deceive the spectators; for they will frankly confess, that truth is not in any circumstance inviolably observed, but in order to procure a more easy reception into the imagination for those extraordinary events, which they represent. But this is a precaution which is not required of comic poets, whose personages and incidents, being of a more familiar kind, enter easily into the conception, and are received without any such formality, even though at first sight they be known to be fictitious, and the pure offspring of the fancy.

This mixture of truth and falsehood in the fables of tragic poets not only serves our present purpose, by showing that the imagination can be satisfied without any absolute belief or assurance; but may in another view be regarded as a very strong confirmation of this system. 'Tis evident, that poets make use of this artifice of borrowing the names of their persons, and the chief events of their poems, from history, in order to procure a more easy reception for the whole, and cause it to make a deeper impression on the fancy and affections. The several incidents of the piece acquire a kind of relation by being united into one poem or representation; and if any of these incidents be an object of belief, it bestows a force and vivacity on the others, which are related to it. The vividness of the first conception diffuses itself along the relations, and is conveyed, as by so many pipes or canals, to every idea that has any communication with the primary one. This indeed can never amount to a perfect assurance; and that because the union among the ideas is in a manner accidental: but still it approaches so near in its influence, as may convince us that they are derived from the same origin. Belief must please the imagination by means of the force and vivacity which attends it; since every idea, which has force and vivacity, is found to be agreeable to that faculty.

To confirm this we may observe, that the assistance is mutual betwixt the judgment and fancy, as well as betwixt the judgment and passion; and that belief not only gives vigour to the imagination, but that a vigorous and strong imagination is of all talents the most proper to procure belief and authority. 'Tis difficult for us to withhold our assent from what is painted out to us in all the colours of eloquence; and the vivacity produced by the fancy is in many cases greater than that which arises from custom and experience. We are hurried away by the lively imagination of our author or companion; and even he himself is often a victim to his own fire and genius.

Nor will it be amiss to remark, that as a lively imagination very often degenerates into madness or folly, and bears it a great resemblance in its operations; so they influence the judgment after the same manner, and produce belief from the very same principles. When the imagination, from any extraordinary ferment of the blood and spirits, acquires such a vivacity as disorders all its powers and faculties, there is no means of distinguishing betwixt truth and falsehood; but every loose fiction or idea, having the same influence as the impressions of the memory, or the conclusions of the judgment, is received on the same footing, and operates with equal force on the passions. A present impression and a customary transition are now no longer necessary to enliven our ideas. Every chimera of the brain is as vivid and intense as any of those inferences, which we formerly dignified with the name of conclusions concerning matters of fact, and sometimes as the present impressions of the senses.

We may observe the same effect of poetry in a lesser degree; and this is common both to poetry and madness, that the vivacity they bestow on the ideas is not derived from the particular situations or connexions of the objects of these ideas, but from the present temper and disposition of the person. But how great soever the pitch may be to which this vivacity rise, 'tis evident, that in poetry it never has the same feeling with that which arises in the mind, when we reason, though even upon the lowest species of probability. The mind can easily distinguish betwixt the one and the other; and whatever emotion the poetical enthusiasm may give to the spirits, 'tis still the mere phantom of belief or persuasion. The case is the same with the idea as with the passion it occasions. There is no passion of the human mind but what may arise from poetry; though, at the same time, the feelings of the passions are very different when excited by poetical fictions, from what they are when they arise from belief and reality. A passion which is disagreeable in real life, may afford the highest entertainment in a tragedy or epic poem. In the latter case it lies not with that weight upon us: it feels less firm and solid, and has no other than the agreeable effect of exciting the spirits, and rousing the attention. The difference in the passions is a clear proof of a like difference in those ideas from which the passions are derived. Where the vivacity arises from a customary conjunction with a present impression, though the imagination may not, in appearance, be so much moved, yet there is always something more forcible and real in its actions than in the fervours of poetry and eloquence. The force of our mental actions in this case, no more than in any other, is not to be measured by the apparent agitation of the mind. A poetical description may have a more sensible effect on the fancy than an historical narration. It may collect more of those circumstances that form a complete image or picture. It may seem to set the object before us in more lively colours. But still the ideas it presents are different to the feeling from those which arise from the memory and the judgment. There is something weak and imperfect amidst all that seeming vehemence of thought and sentiment which attends the fictions of poetry.

We shall afterwards have occasion to remark both the resemblances and differences betwixt a poetical enthusiasm and a serious conviction. In the mean time, I cannot forbear observing, that the great difference in their feeling proceeds, in some measure, from reflection and general rules. We observe, that the vigour of conception which fictions receive from poetry and eloquence, is a circumstance merely accidental, of which every idea is equally susceptible; and that such fictions are connected with nothing that is real. This observation makes us only lend ourselves, so to speak, to the fiction, but causes the idea to feel very different from the eternal established persuasions founded on memory and custom. They are somewhat of the same kind; but the one is much inferior to the other, both in its causes and effects.

A like reflection on general rules keeps us from augmenting our belief upon every increase of the force and vivacity of our ideas. Where an opinion admits of no doubt, or opposite probability, we attribute to it a full conviction; though the want of resemblance, or contiguity, may render its force inferior to that of other opinions. 'Tis thus the understanding corrects the appearances of the senses, and makes us imagine, that an object at twenty foot distance seems even to the eye as large as one of the same dimensions at ten.

We may observe the same effect of poetry in a lesser degree; only with this difference, that the least reflection dissipates the illusions of poetry, and places the objects in their proper light. 'Tis however certain, that in the warmth of a poetical enthusiasm, a poet has a counterfeit belief, and even a kind of vision of his objects; and if there be any shadow of argument to support this belief nothing contributes more to his full conviction than a blaze of poetical figures and images, which have their effect upon the poet himself, as well as upon his readers.

SECTION XI.

OF THE PROBABILITY OF CHANCES.

But in order to bestow on this system its full force and evidence, we must carry our eye from it a moment to consider its consequences, and explain, from the same principles, some other species of reasoning which are derived from the same origin.

Those philosophers who have divided human reason into knowledge and probability, and have defined the first to be that evidence which arises from the comparison of ideas, are obliged to comprehend all our arguments from causes or effects under the general term of probability. But though every one be free to use his terms in what sense he pleases; and accordingly, in the precedent part of this discourse, I have followed this method of expression; 'tis however certain, that in common discourse we readily affirm, that many arguments from causation exceed probability, and may be received as a superior kind of evidence. One would appear ridiculous who would say, that 'tis only probable the sun will rise to-morrow, or that all men must die; though 'tis plain we have no further assurance of these facts than what experience affords us. For this reason t'would perhaps be more convenient, in order at once to preserve the common signification of words, and mark the several degrees of evidence, to distinguish human reason into three kinds, viz. that from knowledge, from proofs, and from probabilities. By knowledge, I mean the assurance arising from the comparison of ideas. By proofs, those arguments which are derived from the relation of cause and effect, and which are entirely free from doubt and uncertainty. By probability, that evidence which is still attended with uncertainty. 'Tis this last species of reasoning I proceed to examine.

Probability or reasoning from conjecture may be divided into two kinds, viz. that which is founded on chance, and that which arises from causes. We shall consider each of these in order.

The idea of cause and effect is derived from experience, which, presenting us with certain objects constantly conjoined with each other, produces such a habit of surveying them in that relation, that we cannot, without a sensible violence, survey them in any other. On the other hand, as chance is nothing real in itself, and, properly speaking, is merely the negation of a cause, its influence on the mind is contrary to that of causation; and 'tis essential to it to leave the imagination perfectly indifferent, either to consider the existence or non-existence of that object which is regarded as contingent. A cause traces the way to our thought, and in a manner forces us to survey such certain objects in such certain relations. Chance can only destroy this determination of the thought, and leave the mind in its native situation of indifference; in which, upon the absence of a cause, 'tis instantly reinstated.

Since, therefore, an entire indifference is essential to chance, no one chance can possibly be superior to another, otherwise than as it is composed of a superior number of equal chances. For if we affirm that one chance can, after any other manner, be superior to another, we must at the same time affirm, that there is something which gives it the superiority, and determines the event rather to that side than the other; that is, in other words, we must allow of a cause, and destroy the supposition of chance, which we had before established. A perfect and total indifference is essential to chance, and one total indifference can never in itself be either superior or inferior to another. This truth is not peculiar to my system, but is acknowledged by every one that forms calculations concerning chances.

And here 'tis remarkable, that though chance and causation be directly contrary, yet 'tis impossible for us to conceive this combination of chances, which is requisite to render one hazard superior to another, without supposing a mixture of causes among the chances, and a conjunction of necessity in some particulars, with a total indifference in others. Where nothing limits the chances, every notion that the most extravagant fancy can form is upon a footing of equality; nor can there be any circumstance to give one the advantage above another. Thus, unless we allow that there are some causes to make the dice fall, and preserve their form in their fall, and lie upon some one of their sides, we can form no calculation concerning the laws of hazard. But supposing these causes to operate, and supposing likewise all the rest to be indifferent and to be determined by chance, 'tis easy to arrive at a notion of a superior combination of chances. A dye that has four sides marked with a certain number of spots, and only two with another, affords us an obvious and easy instance of this superiority. The mind is here limited by the causes to such a precise number and quality of the events; and, at the same time, is undetermined in its choice of any particular event.

Proceeding, then, in that reasoning, wherein we have advanced three steps; that chance is merely the negation of a cause, and produces a total indifference in the mind; that one negation of a cause and one total indifference can never be superior or inferior to another; and that there must always be a mixture of causes among the chances, in order to be the foundation of any reasoning. We are next to consider what effect a superior combination of chances can have upon the mind, and after what manner it influences our judgment and opinion. Here we may repeat all the same arguments we employed in examining that belief which arises from causes; and may prove, after the same manner, that a superior number of chances produces our assent neither by demonstration nor probability. 'Tis indeed evident, that we can never, by the comparison of mere ideas, make any discovery which can be of consequence in this affair, and that 'tis impossible to prove with certainty that any event must fall on that side were there is a superior number of chances. To suppose in this case any certainty, were to overthrow what we have established concerning the opposition of chances, and their perfect equality and indifference.

Should it be said, that though in an opposition of chances, 'tis impossible to determine with certainty on which side the event will fall, yet we can pronounce with certainty, that 'tis more likely and probable 'twill be on that side where there is a superior number of chances, than where there is an inferior: should this be said, I would ask, what is here meant by likelihood and probability? The likelihood and probability of chances is a superior number of equal chances; and consequently, when we say 'tis likely the event will fall on the side which is superior, rather than on the inferior, we do no more than affirm, that where there is a superior number of chances there is actually a superior, and where there is an inferior there is an inferior, which are identical propositions, and of no consequence. The question is, by what means a superior number of equal chances operates upon the mind, and produces belief or assent, since it appears that 'tis neither by arguments derived from demonstration, nor from probability.

In order to clear up this difficulty, we shall suppose a person to take a dye, formed after such a manner as that four of its sides are marked with one figure, or one number of spots, and two with another; and to put this dye into the box with an intention of throwing it: 'tis plain, he must conclude the one figure to be more probable than the other, and give the preference to that which is inscribed on the greatest number of sides. He in a manner believes that this will lie uppermost; though still with hesitation and doubt, in proportion to the number of chances which are contrary: and according as these contrary chances diminish, and the superiority increases on the other side, his belief acquires new degrees of stability and assurance. This belief arises from an operation of the mind upon the simple and limited object before us; and therefore its nature will be the more easily discovered and explained. We have nothing but one single dye to contemplate, in order to comprehend one of the most curious operations of the understanding.

This dye formed as above, contains three circumstances worthy of our attention. First, certain causes, such as gravity, solidity, a cubical figure, &c. which determine it to fall, to preserve its form in its fall, and to turn up one of its sides. Secondly, a certain number of sides, which are supposed indifferent. Thirdly, a certain figure inscribed on each side. These three particulars, form the whole nature of the dye, so far as relates to our present purpose; and consequently are the only circumstances regarded by the mind in its forming a judgment concerning the result of such a throw. Let us therefore consider gradually and carefully what must be the influence of these circumstances on the thought and imagination.

First, we have already observed, that the mind is determined by custom to pass from any cause to its effect, and that upon the appearance of the one, 'tis almost impossible for it not to form an idea of the other. Their constant conjunction in past instances has produced such a habit in the mind, that it always conjoins them in its thought, and infers the existence of the one from that of its usual attendant. When it considers the dye as no longer supported by the box, it cannot without violence regard it as suspended in the air; but naturally places it on the table, and views it as turning up one of its sides. This is the effect of the intermingled causes, which are requisite to our forming any calculation concerning chances.

Secondly, 'tis supposed, that though the dye be necessarily determined to fall, and turn up one of its sides, yet there is nothing to fix the particular side, but that this is determined entirely by chance. The very nature and essence of chance is a negation of causes, and the leaving the mind in a perfect indifference among those events which are supposed contingent. When, therefore, the thought is determined by the causes to consider the dye as falling and turning up one of its sides, the chances present all these sides as equal, and make us consider every one of them, one after another, as alike probable and possible. The imagination passes from the cause, viz. the throwing of the dye, to the effect, viz. the turning up one of the six sides; and feels a kind of impossibility both of stopping short in the way, and of forming any other idea. But as all these six sides are incompatible, and the dye cannot turn up above one at once, this principle directs us not to consider all of them at once as lying uppermost, which we look upon as impossible: neither does it direct us with its entire force to any particular side; for in that case this side would be considered as certain and inevitable; but it directs us to the whole six sides after such a manner as to divide its force equally among them. We conclude in general, that some one of them must result from the throw: we run all of them over in our minds: the determination of the thought is common to all; but no more of its force falls to the share of any one, than what is suitable to its proportion with the rest. 'Tis after this manner the original impulse, and consequently the vivacity of thought arising from the causes, is divided and split in pieces by the intermingled chances.

We have already seen the influence of the two first qualities of the dye, viz. the causes, and the number, and indifference of the sides, and have learned how they give an impulse to the thought, and divide that impulse into as many parts as there are units in the number of sides. We must now consider the effects of the third particular, viz. the figures inscribed on each side. 'Tis evident, that where several sides have the same figure inscribed on them, they must concur in their influence on the mind, and must unite upon one image or idea of a figure all those divided impulses, that were dispersed over the several sides, upon which that figure is inscribed. Were the question only what side will be turned up, these are all perfectly equal, and no one could ever have any advantage above another. But as the question is concerning the figure, and as the same figure is presented by more than one side, 'tis evident that the impulses belonging to all these sides must re-unite in that one figure, and become stronger and more forcible by the union. Four sides are supposed in the present case to have the same figure inscribed on them, and two to have another figure. The impulses of the former are therefore superior to those of the latter. But as the events are contrary, and 'tis impossible both these figures can be turned up; the impulses likewise become contrary, and the inferior destroys the superior, as far as its strength goes. The vivacity of the idea is always proportionable to the degrees of the impulse or tendency to the transition; and belief is the same with the vivacity of the idea, according to the precedent doctrine.

SECTION XII.

OF THE PROBABILITY OF CAUSES.

What I have said concerning the probability of chances, can serve to no other purpose than to assist us in explaining the probability of causes; since 'tis commonly allowed by philosophers, that what the vulgar call chance is nothing but a secret and concealed cause. That species of probability, therefore, is what we must chiefly examine.

The probabilities of causes are of several kinds; but are all derived from the same origin, viz. the association of ideas to a present impression. As the habit which produces the association, arises from the frequent conjunction of objects, it must arrive at its perfection by degrees, and must acquire new force from each instance that falls under our observation. The first instance has little or no force: the second makes some addition to it: the third becomes still more sensible; and 'tis by these slow steps that our judgment arrives at a full assurance. But before it attains this pitch of perfection, it passes through several inferior degrees, and in all of them is only to be esteemed a presumption or probability. The gradation therefore from probabilities to proofs is in many cases insensible; and the difference betwixt these kinds of evidence is more easily perceived in the remote degrees, than in the near and contiguous.

'Tis worthy of remark on this occasion, that though the species of probability here explained be the first in order, and naturally takes place before any entire proof can exist, yet no one, who is arrived at the age of maturity, can any longer be acquainted with it. 'Tis true, nothing is more common than for people of the most advanced knowledge to have attained only an imperfect experience of many particular events; which naturally produces only an imperfect habit and transition: but then we must consider, that the mind, having formed another observation concerning the connexion of causes and effects, gives new force to its reasoning from that observation; and by means of it can build an argument on one single experiment, when duly prepared and examined. What we have found once to follow from any object, we conclude will for ever follow from it; and if this maxim be not always built upon as certain, 'tis not for want of a sufficient number of experiments, but because we frequently meet with instances to the contrary; which leads us to the second species of probability, where there is a contrariety in our experience and observation.

'Twould be very happy for men in the conduct of their lives and actions, were the same objects always conjoined together, and we had nothing to fear but the mistakes of our own judgment, without having any reason to apprehend the uncertainty of nature. But as 'tis frequently found, that one observation is contrary to another, and that causes and effects follow not in the same order, of which we have had experience, we are obliged to vary our reasoning on account of this uncertainty, and take into consideration the contrariety of events. The first question that occurs on this head, is concerning the nature and causes of the contrariety.

The vulgar, who take things according to their first appearance, attribute the uncertainty of events to such an uncertainty in the causes, as makes them often fail of their usual influence, though they meet with no obstacle nor impediment in their operation. But philosophers observing, that almost in every part of nature there is contained a vast variety of springs and principles, which are hid, by reason of their minuteness or remoteness, find that 'tis at least possible the contrariety of events may not proceed from any contingency in the cause, but from the secret operation of contrary causes. This possibility is converted into certainty by farther observation, when they remark, that upon an exact scrutiny, a contrariety of effects always betrays a contrariety of causes, and proceeds from their mutual hinderance and opposition. A peasant can give no better reason for the stopping of any clock or watch than to say, that commonly it does not go right: but an artisan easily perceives, that the same force in the spring or pendulum has always the same influence on the wheels; but fails of its usual effect, perhaps by reason of a grain of dust, which puts a stop to the whole movement. From the observation of several parallel instances, philosophers form a maxim, that the connexion betwixt all causes and effects is equally necessary, and that its seeming uncertainty in some instances proceeds from the secret opposition of contrary causes.

But however philosophers and the vulgar may differ in their explication of the contrariety of events, their inferences from it are always of the same kind, and founded on the same principles. A contrariety of events in the past may give us a kind of hesitating belief for the future, after two several ways. First, by producing an imperfect habit and transition from the present impression to the related idea. When the conjunction of any two objects is frequent, without being entirely constant, the mind is determined to pass from one object to the other; but not with so entire a habit, as when the union is uninterrupted, and all the instances we have ever met with are uniform and of a piece. We find from common experience, in our actions as well as reasonings, that a constant perseverance in any course of life produces a strong inclination and tendency to continue for the future; though there are habits of inferior degrees of force, proportioned to the inferior degrees of steadiness and uniformity in our conduct.

There is no doubt but this principle sometimes takes place, and produces those inferences we draw from contrary phenomena; though I am persuaded that, upon examination, we shall not find it to be the principle that most commonly influences the mind in this species of reasoning. When we follow only the habitual determination of the mind, we make the transition without any reflection, and interpose not a moment's delay betwixt the view of one object, and the belief of that which is often found to attend it. As the custom depends not upon any deliberation, it operates immediately, without allowing any time for reflection. But this method of proceeding we have but few instances of in our probable reasonings; and even fewer than in those, which are derived from the uninterrupted conjunction of objects. In the former species of reasoning we commonly take knowingly into consideration the contrariety of past events; we compare the different sides of the contrariety, and carefully weigh the experiments, which we have on each side: whence we may conclude, that our reasonings of this kind arise not directly from the habit, but in an oblique manner; which we must now endeavour to explain.

'Tis evident, that when an object is attended with contrary effects, we judge of them only by our past experience, and always consider those as possible, which we have observed to follow from it. And as past experience regulates our judgment concerning the possibility of these effects, so it does that concerning their probability; and that effect, which has been the most common, we always esteem the most likely. Here then are two things to be considered, viz. the reasons which determine us to make the past a standard for the future, and the manner how we extract a single judgment from a contrariety of past events.

First we may observe, that the supposition, that the future resembles the past, is not founded on arguments of any kind, but is derived entirely from habit, by which we are determined to expect for the future the same train of objects to which we have been accustomed. This habit or determination to transfer the past to the future is full and perfect; and consequently the first impulse of the imagination in this species of reasoning is endowed with the same qualities.

But, secondly, when in considering past experiments we find them of a contrary nature, this determination, though full and perfect in itself, presents us with no steady object, but offers us a number of disagreeing images in a certain order and proportion. The first impulse therefore is here broke into pieces, and diffuses itself over all those images, of which each partakes an equal share of that force and vivacity that is derived from the impulse. Any of these past events may again happen; and we judge, that when they do happen, they will be mixed in the same proportion as in the past.

If our intention, therefore, be to consider the proportions of contrary events in a great number of instances, the images presented by our past experience must remain in their first form, and preserve their first proportions. Suppose, for instance, I have found, by long observation, that of twenty ships which go to sea, only nineteen return. Suppose I see at present twenty ships that leave the port: I transfer my past experience to the future, and represent to myself nineteen of these ships as returning in safety, and one as perishing. Concerning this there can be no difficulty. But as we frequently run over those several ideas of past events, in order to form a judgment concerning one single event, which appears uncertain; this consideration must change the first form of our ideas, and draw together the divided images presented by experience; since 'tis to it we refer the determination of that particular event, upon which we reason. Many of these images are supposed to concur, and a superior number to concur on one side. These agreeing images unite together, and render the idea more strong and lively, not only than a mere fiction of the imagination, but also than any idea, which is supported by a lesser number of experiments. Each new experiment is as a new stroke of the pencil, which bestows an additional vivacity on the colours, without either multiplying or enlarging the figure. This operation of the mind has been so fully explained in treating of the probability of chance, that I need not here endeavour to render it more intelligible. Every past experiment may be considered as a kind of chance; it being uncertain to us, whether the object will exist conformable to one experiment or another: and for this reason every thing that has been said on the one subject is applicable to both.

Thus, upon the whole, contrary experiments produce an imperfect belief, either by weakening the habit, or by dividing and afterwards joining in different parts, that perfect habit, which makes us conclude in general, that instances, of which we have no experience, must necessarily resemble those of which we have.

To justify still farther this account of the second species of probability, where we reason with knowledge and reflection from a contrariety of past experiments, I shall propose the following considerations, without fearing to give offence by that air of subtilty, which attends them. Just reasoning ought still, perhaps, to retain its force, however subtile; in the same manner as matter preserves its solidity in the air, and fire, and animal spirits, as well as in the grosser and more sensible forms.

First, we may observe, that there is no probability so great as not to allow of a contrary possibility; because otherwise 'twould cease to be a probability, and would become a certainty. That probability of causes, which is most extensive, and which we at present examine, depends on a contrariety of experiments; and 'tis evident an experiment in the past proves at least a possibility for the future.

Secondly, the component parts of this possibility and probability are of the same nature, and differ in number only, but not in kind. It has been observed, that all single chances are entirely equal, and that the only circumstance, which can give any event that is contingent a superiority over another, is a superior number of chances. In like manner, as the uncertainty of causes is discovered by experience, which presents us with a view of contrary events, 'tis plain that, when we transfer the past to the future, the known to the unknown, every past experiment has the same weight, and that 'tis only a superior number of them, which can throw the balance on any side. The possibility, therefore, which enters into every reasoning of this kind, is composed of parts, which are of the same nature both among themselves, and with those that compose the opposite probability.

Thirdly, we may establish it as a certain maxim, that in all moral as well as natural phenomena, wherever any cause consists of a number of parts, and the effect increases or diminishes, according to the variation of that number, the effect, properly speaking, is a compounded one, and arises from the union of the several effects, that proceed from each part of the cause. Thus, because the gravity of a body increases or diminishes by the increase or diminution of its parts, we conclude that each part contains this quality, and contributes to the gravity of the whole. The absence or presence of a part of the cause is attended with that of a proportionable part of the effect. This connexion or constant conjunction sufficiently proves the one part to be the cause of the other. As the belief, which we have of any event, increases or diminishes according to the number of chances or past experiments, 'tis to be considered as a compounded effect, of which each part arises from a proportionable number of chances or experiments.

Let us now join these three observations, and see what conclusion we can draw from them. To every probability there is an opposite possibility. This possibility is composed of parts that are entirely of the same nature with those of the probability; and consequently have the same influence on the mind and understanding. The belief which attends the probability, is a compounded effect, and is formed by the concurrence of the several effects, which proceed from each part of the probability. Since, therefore, each part of the probability contributes to the production of the belief, each part of the possibility must have the same influence on the opposite side; the nature of these parts being entirely the same. The contrary belief attending the possibility, implies a view of a certain object, as well as the probability does an opposite view. In this particular, both these degrees of belief are alike. The only manner then, in which the superior number of similar component parts in the one can exert its influence, and prevail above the inferior in the other, is by producing a stronger and more lively view of its object. Each part presents a particular view; and all these views uniting together produce one general view, which is fuller and more distinct by the greater number of causes or principles from which it is derived.

The component parts of the probability and possibility being alike in their nature, must produce like effects; and the likeness of their effects consists in this, that each of them presents a view of a particular object. But though these parts be alike in their nature, they are very different in their quantity and number; and this difference must appear in the effect as well as the similarity. Now, as the view they present is in both cases full and entire, and comprehends the object in all its parts, 'tis impossible that, in this particular, there can be any difference; nor is there any thing but a superior vivacity in the probability, arising from the concurrence of a superior number of views, which can distinguish these effects.

Here is almost the same argument in a different light. All our reasonings concerning the probability of causes are founded on the transferring of past to future. The transferring of any past experiment to the future is sufficient to give us a view of the object; whether that experiment be single or combined with others of the same kind; whether it be entire, or opposed by others of a contrary kind. Suppose then it acquires both these qualities of combination and opposition, it loses not, upon that account, its former power of presenting a view of the object, but only concurs with and opposes other experiments that have a like influence. A question, therefore, may arise concerning the manner both of the concurrence and opposition. As to the concurrence there is only the choice left betwixt these two hypotheses. First, that the view of the object, occasioned by the transference of each past experiment, preserves itself entire, and only multiplies the number of views. Or, secondly, that it runs into the other similar and correspondent views, and gives them a superior degree of force and vivacity. But that the first hypothesis is erroneous, is evident from experience, which informs us, that the belief attending any reasoning consists in one conclusion, not in a multitude of similar ones, which would only distract the mind, and, in many cases, would be too numerous to be comprehended distinctly by any finite capacity. It remains, therefore, as the only reasonable opinion, that these similar views run into each other and unite their forces; so as to produce a stronger and clearer view than what arises from any one alone. This is the manner in which past experiments concur when they are transferred to any future event. As to the manner of their opposition,'tis evident that, as the contrary views are incompatible with each other, and 'tis impossible the object can at once exist conformable to both of them, their influence becomes mutually destructive, and the mind is determined to the superior only with that force which remains after subtracting the inferior.

I am sensible how abstruse all this reasoning must appear to the generality of readers, who, not being accustomed to such profound reflections on the intellectual faculties of the mind, will be apt to reject as chimerical whatever strikes not in with the common received notions, and with the easiest and most obvious principles of philosophy. And, no doubt, there are some pains required to enter into these arguments; though perhaps very little are necessary to perceive the imperfection of every vulgar hypothesis on this subject, and the little light, which philosophy can yet afford us in such sublime and such curious speculations. Let men be once fully persuaded of these two principles, that there is nothing in any object, considered in itself, which can afford us a reason for drawing a conclusion beyond it; and, that even after the observation of the frequent or constant conjunction of objects, we have no reason to draw any inference concerning any object beyond those of which we have had experience; I say, let men be once fully convinced of these two principles, and this will throw them so loose from all common systems, that they will make no difficulty of receiving any, which may appear the most extraordinary. These principles we have found to be sufficiently convincing, even with regard to our most certain reasonings from causation: but I shall venture to affirm, that with regard to these conjectural or probable reasonings they still acquire a new degree of evidence.

First,'tis obvious that, in reasonings of this kind, 'tis not the object presented to us, which, considered in itself, affords us any reason to draw a conclusion concerning any other object or event. For as this latter object is supposed uncertain, and as the uncertainty is derived from a concealed contrariety of causes in the former, were any of the causes placed in the known qualities of that object, they would no longer be concealed, nor would our conclusion be uncertain.

But, secondly,'tis equally obvious in this species of reasoning, that if the transference of the past to the future were founded merely on a conclusion of the understanding, it could never occasion any belief or assurance. When we transfer contrary experiments to the future, we can only repeat these contrary experiments with their particular proportions; which could not produce assurance in any single event upon which we reason, unless the fancy melted together all those images that concur, and extracted from them one single idea or image, which is intense and lively in proportion to the number of experiments from which it is derived, and their superiority above their antagonists. Our past experience presents no determinate object; and as our belief, however faint, fixes itself on a determinate object, 'tis evident that the belief arises not merely from the transference of past to future, but from some operation of the fancy conjoined with it. This may lead us to conceive the manner in which that faculty enters into all our reasonings.

I shall conclude this subject with two reflections which may deserve our attention. The first may be explained after this manner: When the mind forms a reasoning concerning any matter of fact, which is only probable, it casts its eye backward upon past experience, and, transferring it to the future, is presented with so many contrary views of its object, of which those that are of the same kind uniting together and running into one act of the mind, serve to fortify and enliven it. But suppose that this multitude of views or glimpses of an object proceeds not from experience, but from a voluntary act of the imagination; this effect does not follow, or, at least, follows not in the same degree. For though custom and education produce belief by such a repetition as is not derived from experience, yet this requires a long tract of time, along with a very frequent and undesigned repetition. In general we may pronounce, that a person, who would voluntarily repeat any idea in his mind, though supported by one past experience, would be no more inclined to believe the existence of its object, than if he had contented himself with one survey of it. Beside the effect of design, each act of the mind, being separate and independent, has a separate influence, and joins not its force with that of its fellows. Not being united by any common object producing them, they have no relation to each other; and consequently make no transition or union of forces. This phenomenon we shall understand better afterwards.

My second reflection is founded on those large probabilities which the mind can judge of, and the minute differences it can observe betwixt them. When the chances or experiments on one side amount to ten thousand, and on the other to ten thousand and one, the judgment gives the preference to the latter upon account of that superiority; though 'tis plainly impossible for the mind to run over every particular view, and distinguish the superior vivacity of the image arising from the superior number, where the difference is so inconsiderable. We have a parallel instance in the affections. 'Tis evident, according to the principles above mentioned, that when an object produces any passion in us, which varies according to the different quantity of the object; I say, 'tis evident, that the passion, properly speaking, is not a simple emotion, but a compounded one, of a great number of weaker passions, derived from a view of each part of the object; for otherwise 'twere impossible the passion should increase by the increase of these parts. Thus, a man who desires a thousand pounds has, in reality, a thousand or more desires which, uniting together, seem to make only one passion; though the composition evidently betrays itself upon every alteration of the object, by the preference he gives to the larger number, if superior only by an unit. Yet nothing can be more certain, than that so small a difference would not be discernible in the passions, nor could render them distinguishable from each other. The difference, therefore, of our conduct in preferring the greater number depends not upon our passions, but upon custom and general rules. We have found in a multitude of instances that the augmenting the numbers of any sum augments the passion, where the numbers are precise and the difference sensible. The mind can perceive, from its immediate feeling, that three guineas produce a greater passion than two; and this it transfers to larger numbers, because of the resemblance; and by a general rule assigns to a thousand guineas a stronger passion than to nine hundred and ninety-nine. These general rules we shall explain presently.

But beside these two species of probability, which are derived from an imperfect experience and from contrary causes, there is a third arising from analogy, which differs from them in some material circumstances. According to the hypothesis above explained, all kinds of reasoning from causes or effects are founded on two particulars, viz. the constant conjunction of any two objects in all past experience, and the resemblance of a present object to any one of them. The effect of these two particulars is, that the present object invigorates and enlivens the imagination; and the resemblance, along with the constant union, conveys this force and vivacity to the related idea; which we are therefore said to believe or assent to. If you weaken either the union or resemblance, you weaken the principle of transition, and of consequence that belief which arises from it. The vivacity of the first impression cannot be fully conveyed to the related idea, either where the conjunction of their objects is not constant, or where the present impression does not perfectly resemble any of those whose union we are accustomed to observe. In those probabilities of chance and causes above explained, 'tis the constancy of the union which is diminished; and in the probability derived from analogy, 'tis the resemblance only which is affected. Without some degree of resemblance, as well as union, 'tis impossible there can be any reasoning. But as this resemblance admits of many different degrees, the reasoning becomes proportionably more or less firm and certain. An experiment loses of its force, when transferred to instances which are not exactly resembling; though 'tis evident it may still retain as much as may be the foundation of probability, as long as there is any resemblance remaining.

SECTION XIII.

OF UNPHILOSOPHICAL PROBABILITY.

All these kinds of probability are received by philosophers, and allowed to be reasonable foundations of belief and opinion. But there are others that are derived from the same principles, though they have not had the good fortune to obtain the same sanction. The first probability of this kind may be accounted for thus. The diminution of the union and of the resemblance, as above explained, diminishes the facility of the transition, and by that means weakens the evidence; and we may farther observe, that the same diminution of the evidence will follow from a diminution of the impression, and from the shading of those colours under which it appears to the memory or senses. The argument which we found on any matter of fact we remember is more or less convincing, according as the fact is recent or remote; and though the difference in these degrees of evidence be not received by philosophy as solid and legitimate; because in that case an argument must have a different force to-day from what it shall have a month hence; yet, notwithstanding the opposition of philosophy, 'tis certain this circumstance has a considerable influence on the understanding, and secretly changes the authority of the same argument, according to the different times in which it is proposed to us. A greater force and vivacity in the impression naturally conveys a greater to the related idea; and 'tis on the degrees of force and vivacity that the belief depends, according to the foregoing system.

There is a second difference which we may frequently observe in our degrees of belief and assurance, and which never fails to take place, though disclaimed by philosophers. An experiment that is recent and fresh in the memory, affects us more than one that is in some measure obliterated; and has a superior influence on the judgment as well as on the passions. A lively impression produces more assurance than a faint one, because it has more original force to communicate to the related idea, which thereby acquires a greater force and vivacity. A recent observation has a like effect; because the custom and transition is there more entire, and preserves better the original force in the communication. Thus a drunkard, who has seen his companion die of a debauch, is struck with that instance for some time, and dreads a like accident for himself; but as the memory of it decays away by degrees, his former security returns, and the danger seems less certain and real.

I add, as a third instance of this kind, that though our reasonings from proofs and from probabilities be considerably different from each other, yet the former species of reasoning often degenerates insensibly into the latter, by nothing but the multitude of connected arguments. 'Tis certain, that when an inference is drawn immediately from an object, without any intermediate cause or effect, the conviction is much stronger, and the persuasion more lively, than when the imagination is carried through a long chain of connected arguments, however infallible the connexion of each link may be esteemed. 'Tis from the original impression that the vivacity of all the ideas is derived, by means of the customary transition of the imagination; and 'tis evident this vivacity must gradually decay in proportion to the distance, and must lose somewhat in each transition. Sometimes this distance has a greater influence than even contrary experiments would have; and a man may receive a more lively conviction from a probable reasoning which is close and immediate, than from a long chain of consequences, though just and conclusive in each part. Nay, 'tis seldom such reasonings produce any conviction; and one must have a very strong and firm imagination to preserve the evidence to the end, where it passes through so many stages.

But here it may not be amiss to remark a very curious phenomenon which the present subject suggests to us. 'Tis evident there is no point of ancient history, of which we can have any assurance, but by passing through many millions of causes and effects, and through a chain of arguments of almost an immeasurable length. Before the knowledge of the fact could come to the first historian, it must be conveyed through many mouths; and after it is committed to writing, each new copy is a new object, of which the connexion with the foregoing is known only by experience and observation. Perhaps therefore it may be concluded, from the precedent reasoning, that the evidence of all ancient history must now be lost, or at least will be lost in time, as the chain of causes increases, and runs on to a greater length. But as it seems contrary to common sense to think, that if the republic of letters and the art of printing continue on the same footing as at present, our posterity, even after a thousand ages, can ever doubt if there has been such a man as Julius Cæsar; this may be considered as an objection to the present system. If belief consisted only in a certain vivacity, conveyed from an original impression, it would decay by the length of the transition, and must at last be utterly extinguished. And, vice versa, if belief, on some occasions, be not capable of such an extinction, it must be something different from that vivacity.

Before I answer this objection I shall observe, that from this topic there has been borrowed a very celebrated argument against the Christian Religion; but with this difference, that the connexion betwixt each link of the chain in human testimony has been there supposed not to go beyond probability, and to be liable to a degree of doubt and uncertainty. And indeed it must be confessed, that in this manner of considering the subject (which, however, is not a true one), there is no history or tradition but what must in the end lose all its force and evidence. Every new probability diminishes the original conviction; and, however great that conviction may be supposed, 'tis impossible it can subsist under such reiterated diminutions. This is true in general, though we shall find afterwards,[9] that there is one very memorable exception, which is of vast consequence in the present subject of the understanding.

Meanwhile, to give a solution of the preceding objection upon the supposition that historical evidence amounts at first to an entire proof, let us consider, that, though the links are innumerable that connect any original fact with the present impression, which is the foundation of belief, yet they are all of the same kind, and depend on the fidelity of printers and copyists. One edition passes into another, and that into a third, and so on, till we come to that volume we peruse at present. There is no variation in the steps. After we know one, we know all of them; and after we have made one, we can have no scruple as to the rest. This circumstance alone preserves the evidence of history, and will perpetuate the memory of the present age to the latest posterity. If all the long chain of causes and effects, which connect any past event with any volume of history, were composed of parts different from each other, and which 'twere necessary for the mind distinctly to conceive, 'tis impossible we should preserve to the end any belief or evidence. But as most of these proofs are perfectly resembling, the mind runs easily along them, jumps from one part to another with facility, and forms but a confused and general notion of each link. By this means, a long chain of argument has as little effect in diminishing the original vivacity, as a much shorter would have if composed of parts which were different from each other, and of which each required a distinct consideration.

A fourth unphilosophical species of probability is that derived from general rules, which we rashly form to ourselves, and which are the source of what we properly call prejudice. An Irishman cannot have wit, and a Frenchman cannot have solidity; for which reason, though the conversation of the former in any instance be visibly very agreeable, and of the latter very judicious, we have entertained such a prejudice against them, that they must be dunces or fops in spite of sense and reason. Human nature is very subject to errors of this kind, and perhaps this nation as much as any other.

Should it be demanded why men form general rules, and allow them to influence their judgment, even contrary to present observation and experience, I should reply, that in my opinion it proceeds from those very principles on which all judgments concerning causes and effects depend. Our judgments concerning cause and effect are derived from habit and experience; and when we have been accustomed to see one object united to another, our imagination passes from the first to the second by a natural transition, which precedes reflection, and which cannot be prevented by it. Now, 'tis the nature of custom not only to operate with its full force, when objects are presented that are exactly the same with those to which we have been accustomed, but also to operate in an inferior degree when we discover such as are similar; and though the habit loses somewhat of its force by every difference, yet 'tis seldom entirely destroyed where any considerable circumstances remain the same. A man who has contracted a custom of eating fruit by the use of pears or peaches, will satisfy himself with melons where he cannot find his favourite fruit; as one, who has become a drunkard by the use of red wines, will be carried almost with the same violence to white, if presented to him. From this principle I have accounted for that species of probability, derived from analogy, where we transfer our experience in past instances to objects which are resembling, but are not exactly the same with those concerning which we have had experience. In proportion as the resemblance decays, the probability diminishes, but still has some force as long as there remain any traces of the resemblance.

This observation we may carry farther, and may remark, that though custom be the foundation of all our judgments, yet sometimes it has an effect on the imagination in opposition to the judgment, and produces a contrariety in our sentiments concerning the same object. I explain myself. In almost all kinds of causes there is a complication of circumstances, of which some are essential, and others superfluous; some are absolutely requisite to the production of the effect, and others are only conjoined by accident. Now we may observe, that when these superfluous circumstances are numerous and remarkable, and frequently conjoined with the essential, they have such an influence on the imagination, that even in the absence of the latter they carry us on to the conception of the usual effect, and give to that conception a force and vivacity which make it superior to the mere fictions of the fancy. We may correct this propensity by a reflection on the nature of those circumstances; but 'tis still certain, that custom takes the start, and gives a bias to the imagination.

To illustrate this by a familiar instance, let us consider the case of a man, who, being hung out from a high tower in a cage of iron, cannot forbear trembling when he surveys the precipice below him, though he knows himself to be perfectly secure from falling, by his experience of the solidity of the iron which supports him, and though the ideas of fall and descent, and harm and death, be derived solely from custom and experience. The same custom goes beyond the instances from which it is derived, and to which it perfectly corresponds; and influences his ideas of such objects as are in some respect resembling, but fall not precisely under the same rule. The circumstances of depth and descent strike so strongly upon him, that their influence cannot be destroyed by the contrary circumstances of support and solidity, which ought to give him a perfect security. His imagination runs away with its object, and excites a passion proportioned to it. That passion returns back upon the imagination, and enlivens the idea; which lively idea has a new influence on the passion, and in its turn augments its force and violence: and both his fancy and affections, thus mutually supporting each other, cause the whole to have a very great influence upon him.

But why need we seek for other instances, while the present subject of philosophical probabilities offers us so obvious an one, in the opposition betwixt the judgment and imagination, arising from these effects of custom? According to my system, all reasonings are nothing but the effects of custom, and custom has no influence, but by enlivening the imagination, and giving us a strong conception of any object. It may therefore be concluded, that our judgment and imagination can never be contrary, and that custom cannot operate on the latter faculty after such a manner, as to render it opposite to the former. This difficulty we can remove after no other manner, than by supposing the influence of general rules. We shall afterwards[10] take notice of some general rules, by which we ought to regulate our judgment concerning causes and effects; and these rules are formed on the nature of our understanding, and on our experience of its operations in the judgments we form concerning objects. By them we learn to distinguish the accidental circumstances from the efficacious causes; and when we find that an effect can be produced without the concurrence of any particular circumstance, we conclude that that circumstance makes not a part of the efficacious cause, however frequently conjoined with it. But as this frequent conjunction necessarily makes it have some effect on the imagination, in spite of the opposite conclusion from general rules, the opposition of these two principles produces a contrariety in our thoughts, and causes us to ascribe the one inference to our judgment, and the other to our imagination. The general rule is attributed to our judgment, as being more extensive and constant; the exception to the imagination, as being more capricious and uncertain.

Thus, our general rules are in a manner set in opposition to each other. When an object appears, that resembles any cause in very considerable circumstances, the imagination naturally carries us to a lively conception of the usual effect, though the object be different in the most material and most efficacious circumstances from that cause. Here is the first influence of general rules. But when we take a review of this act of the mind, and compare it with the more general and authentic operations of the understanding, we find it to be of an irregular nature, and destructive of all the most established principles of reasonings, which is the cause of our rejecting it. This is a second influence of general rules, and implies the condemnation of the former. Sometimes the one, sometimes the other prevails, according to the disposition and character of the person. The vulgar are commonly guided by the first, and wise men by the second. Meanwhile the sceptics may here have the pleasure of observing a new and signal contradiction in our reason, and of seeing all philosophy ready to be subverted by a principle of human nature, and again saved by a new direction of the very same principle. The following of general rules is a very unphilosophical species of probability; and yet 'tis only by following them that we can correct this, and all other unphilosophical probabilities.

Since we have instances where general rules operate on the imagination, even contrary to the judgment, we need not be surprised to see their effects increase, when conjoined with that latter faculty, and to observe that they bestow on the ideas they present to us a force superior to what attends any other. Every one knows there is an indirect manner of insinuating praise or blame, which is much less shocking than the open flattery or censure of any person. However he may communicate his sentiments by such secret insinuations, and make them known with equal certainty as by the open discovery of them, 'tis certain that their influence is not equally strong and powerful. One who lashes me with concealed strokes of satire, moves not my indignation to such a degree, as if he flatly told me I was a fool and a coxcomb; though I equally understand his meaning, as if he did. This difference is to be attributed to the influence of general rules.

Whether a person openly abuses me, or slily intimates his contempt, in neither case do I immediately perceive his sentiment or opinion; and 'tis only by signs, that is, by its effects, I become sensible of it. The only difference then, betwixt these two cases, consists in this, that in the open discovery of his sentiments he makes use of signs, which are general and universal; and in the secret intimation employs such as are more singular and uncommon. The effect of this circumstance is, that the imagination, in running from the present impression to the absent idea, makes the transition with greater facility, and consequently conceives the object with greater force, where the connexion is common and universal, than where it is more rare and particular. Accordingly, we may observe, that the open declaration of our sentiments is called the taking off the mask, as the secret intimation of our opinions is said to be the veiling of them. The difference betwixt an idea produced by a general connexion, and that arising from a particular one, is here compared to the difference betwixt an impression and an idea. This difference in the imagination has a suitable effect on the passions, and this effect is augmented by another circumstance. A secret intimation of anger or contempt shows that we still have some consideration for the person, and avoid the directly abusing him. This makes a concealed satire less disagreeable, but still this depends on the same principle. For if an idea were not more feeble, when only intimated, it would never be esteemed a mark of greater respect to proceed in this method than in the other.

Sometimes scurrility is less displeasing than delicate satire, because it revenges us in a manner for the injury at the very time it is committed, by affording us a just reason to blame and contemn the person who injures us. But this phenomenon likewise depends upon the same principle. For why do we blame all gross and injurious language, unless it be, because we esteem it contrary to good breeding and humanity? And why is it contrary, unless it be more shocking than any delicate satire? The rules of good breeding condemn whatever is openly disobliging, and gives a sensible pain and confusion to those with whom we converse. After this is once established, abusive language is universally blamed, and gives less pain upon account of its coarseness and incivility, which render the person despicable that employs it. It becomes less disagreeable, merely because originally it is more so; and 'tis more disagreeable, because it affords an inference by general and common rules that are palpable and undeniable.

To this explication of the different influence of open and concealed flattery or satire, I shall add the consideration of another phenomenon, which is analogous to it. There are many particulars in the point of honour, both of men and women, whose violations, when open and avowed, the world never excuses, but which it is more apt to overlook, when the appearances are saved, and the transgression is secret and concealed. Even those who know with equal certainty that the fault is committed, pardon it more easily, when the proofs seem in some measure oblique and equivocal, than when they are direct and undeniable. The same idea is presented in both cases, and, properly speaking, is equally assented to by the judgment; and yet its influence is different, because of the different manner in which it is presented.

Now, if we compare these two cases, of the open and concealed violations of the laws of honour, we shall find, that the difference betwixt them consists in this, that in the first case the sign, from which we infer the blameable action, is single, and suffices alone to be the foundation of our reasoning and judgment; whereas in the latter the signs are numerous, and decide little or nothing when alone and unaccompanied with many minute circumstances, which are almost imperceptible. But 'tis certainly true, that any reasoning is always the more convincing, the more single and united it is to the eye, and the less exercise it gives to the imagination to collect all its parts, and run from them to the correlative idea, which forms the conclusion. The labour of the thought disturbs the regular progress of the sentiments, as we shall observe presently.[11] The idea strikes not on us with such vivacity, and consequently has no such influence on the passion and imagination.

From the same principles we may account for those observations of the Cardinal de Retz, that there are many things in which the world wishes to be deceived, and that it more easily excuses a person in acting than in talking contrary to the decorum of his profession and character. A fault in words is commonly more open and distinct than one in actions, which admit of many palliating excuses, and decide not so clearly concerning the intention and views of the actor.

Thus it appears, upon the whole, that every kind of opinion or judgment which amounts not to knowledge, is derived entirely from the force and vivacity of the perception, and that these qualities constitute in the mind what we call the belief of the existence of any object. This force and this vivacity are most conspicuous in the memory; and therefore our confidence in the veracity of that faculty is the greatest imaginable, and equals in many respects the assurance of a demonstration. The next degree of these qualities is that derived from the relation of cause and effect; and this too is very great, especially when the conjunction is found by experience to be perfectly constant, and when the object, which is present to us, exactly resembles those, of which we have had experience. But below this degree of evidence there are many others, which have an influence on the passions and imagination, proportioned to that degree of force and vivacity, which they communicate to the ideas. 'Tis by habit we make the transition from cause to effect; and 'tis from some present impression we borrow that vivacity, which we diffuse over the correlative idea. But when we have not observed a sufficient number of instances to produce a strong habit; or when these instances are contrary to each other; or when the resemblance is not exact; or the present impression is faint and obscure; or the experience in some measure obliterated from the memory; or the connexion dependent on a long chain of objects; or the inference derived from general rules, and yet not conformable to them: in all these cases the evidence diminishes by the diminution of the force and intenseness of the idea. This therefore is the nature of the judgment and probability.

What principally gives authority to this system is, beside the undoubted arguments, upon which each part is founded, the agreement of these parts, and the necessity of one to explain another. The belief which attends our memory is of the same nature with that which is derived from our judgments: nor is there any difference betwixt that judgment which is derived from a constant and uniform connexion of causes and effects, and that which depends upon an interrupted and uncertain. 'Tis indeed evident, that in all determinations where the mind decides from contrary experiments, 'tis first divided within itself, and has an inclination to either side in proportion to the number of experiments we have seen and remember. This contest is at last determined to the advantage of that side where we observe a superior number of these experiments; but still with a diminution of force in the evidence correspondent to the number of the opposite experiments. Each possibility, of which the probability is composed, operates separately upon the imagination; and 'tis the larger collection of possibilities, which at last prevails, and that with a force proportionable to its superiority. All these phenomena lead directly to the precedent system; nor will it ever be possible upon any other principles to give a satisfactory and consistent explication of them. Without considering these judgments as the effects of custom on the imagination, we shall lose ourselves in perpetual contradiction and absurdity.

SECTION XIV.

OF THE IDEA OF NECESSARY CONNEXION.

Having thus explained the manner in which we reason beyond our immediate impressions, and conclude that such particular causes must have such particular effects; we must now return upon our footsteps to examine that question[12] which first occurred to us, and which we dropped in our way, viz. What is our idea of necessity, when we say that two objects are necessarily connected together? Upon this head I repeat, what I have often had occasion to observe, that as we have no idea that is not derived from an impression, we must find some impression that gives rise to this idea of necessity, if we assert we have really such an idea. In order to this, I consider in what objects necessity is commonly supposed to lie; and, finding that it is always ascribed to causes and effects, I turn my eye to two objects supposed to be placed in that relation, and examine them in all the situations of which they are susceptible. I immediately perceive that they are contiguous in time and place, and that the object we call cause precedes the other we call effect. In no one instance can I go any farther, nor is it possible for me to discover any third relation betwixt these objects. I therefore enlarge my view to comprehend several instances, where I find like objects always existing in like relations of contiguity and succession. At first sight this seems to serve but little to my purpose. The reflection on several instances only repeats the same objects; and therefore can never give rise to a new idea. But upon farther inquiry I find, that the repetition is not in every particular the same, but produces a new impression, and by that means the idea which I at present examine. For after a frequent repetition I find, that upon the appearance of one of the objects, the mind is determined by custom to consider its usual attendant, and to consider it in a stronger light upon account of its relation to the first object. 'Tis this impression, then, or determination, which affords me the idea of necessity.

I doubt not but these consequences will at first sight be received without difficulty, as being evident deductions from principles which we have already established, and which we have often employed in our reasonings. This evidence, both in the first principles and in the deductions, may seduce us unwarily into the conclusion, and make us imagine it contains nothing extraordinary, nor worthy of our curiosity. But though such an inadvertence may facilitate the reception of this reasoning, 'twill make it be the more easily forgot; for which reason I think it proper to give warning, that I have just now examined one of the most sublime questions in philosophy, viz. that concerning the power and efficacy of causes, where all the sciences seem so much interested. Such a warning will naturally rouse up the attention of the reader, and make him desire a more full account of my doctrine, as well as of the arguments on which it is founded. This request is so reasonable, that I cannot refuse complying with it; especially as I am hopeful that these principles, the more they are examined, will acquire the more force and evidence.

There is no question which, on account of its importance, as well as difficulty, has caused more disputes both among ancient and modern philosophers, than this concerning the efficacy of causes, or that quality which makes them be followed by their effects. But before they entered upon these disputes, methinks it would not have been improper to have examined what idea we have of that efficacy, which is the subject of the controversy. This is what I find principally wanting in their reasonings, and what I shall here endeavour to supply.

I begin with observing, that the terms of efficacy, agency, power, force, energy, necessity, connexion, and productive quality, are all nearly synonymous; and therefore 'tis an absurdity to employ any of them in defining the rest. By this observation we reject at once all the vulgar definitions which philosophers have given of power and efficacy; and instead of searching for the idea in these definitions, must look for it in the impressions from which it is originally derived. If it be a compound idea, it must arise from compound impressions. If simple, from simple impressions.

I believe the most general and most popular explication of this matter, is to say,[13] that finding from experience that there are several new productions in matter, such as the motions and variations of body, and concluding that there must somewhere be a power capable of producing them, we arrive at last by this reasoning at the idea of power and efficacy. But to be convinced that this explication is more popular than philosophical, we need but reflect on two very obvious principles. First, that reason alone can never give rise to any original idea; and, secondly, that reason, as distinguished from experience, can never make us conclude that a cause or productive quality is absolutely requisite to every beginning of existence. Both these considerations have been sufficiently explained; and therefore shall not at present be any farther insisted on.

I shall only infer from them, that since reason can never give rise to the idea of efficacy, that idea must be derived from experience, and from some particular instances of this efficacy, which make their passage into the mind by the common channels of sensation or reflection. Ideas always represent their objects or impressions; and vice versa, there are some objects necessary to give rise to every idea. If we pretend, therefore, to have any just idea of this efficacy, we must produce some instance wherein the efficacy is plainly discoverable to the mind, and its operations obvious to our consciousness or sensation. By the refusal of this, we acknowledge, that the idea is impossible and imaginary; since the principle of innate ideas, which alone can save us from this dilemma, has been already refuted, and is now almost universally rejected in the learned world. Our present business, then, must be to find some natural production, where the operation and efficacy of a cause can be clearly conceived and comprehended by the mind, without any danger of obscurity or mistake.