 FILE 24 OF A TREATUS OF HUMAN NATURE by David Hume Volume 1 This LibriVox recording is in the public domain, recording by George Yeager. Book 1, Part 3, Section 9, of the effects of other relations and other habits. However convincing the foregoing arguments may appear, we must not rest contented with them, but must turn the subject on every side in order to find some new points of view from which we may illustrate and confirm such extraordinary and such fundamental principles. A scrupulous hesitation to receive any new hypothesis is so laudable a disposition in philosophers and so necessary to the examination of truth that it deserves to be complied with, and requires that every argument be produced which may tend to their satisfaction and every objection removed which may stop them in their reasoning. I have often observed that beside cause and effect the two relations of resemblance and contiguity are to be considered as associating principles of thought, and as capable of conveying the imagination from one idea to another. I have also observed that when of two objects connected together by any of these relations, one is immediately present to the memory or senses, not only the mind is conveyed to its correlative by means of the associating principle, but likewise conceives it with an additional force and vigor by the united operation of that principle and of the present impression. All this I have observed in order to confirm by analogy my explication of our judgments concerning cause and effect. But this very argument may perhaps be turned against me, and instead of the confirmation of my hypothesis may become an objection to it. For it may be said that if all the parts of that hypothesis be true, that is, that these three species of relation are derived from the same principles, that their effects in enforcing and enlivening our ideas are the same, and that belief is nothing but a more forcible and vivid conception of an idea, it should follow that that action of the mind may not only be derived from the relation of cause and effect, but also from those of contiguity and resemblance. But as we find by experience that belief arises only from causation, and that we can draw no inference from one object to another, except they be connected by this relation, we may conclude that there is some error in that reasoning which leads us into such difficulties. This is the objection. Let us now consider its solution. It is evident that whatever is present to the memory, striking upon the mind with a vivacity which resembles an immediate impression, must become of considerable moment in all the operations of the mind, and must easily distinguish itself above the mere fictions of the imagination. Of these impressions or ideas of the memory, we form a kind of system comprehending whatever we remember to have been present, either to our internal perception or senses, and every particular of that system joined to the present impressions, we are pleased to call a reality. But the mind stops not here, for finding that with this system of perceptions there is another connected by custom, or if you will, by the relation of cause or effect, it proceeds to the consideration of their ideas, and as it feels that it is in a manner necessarily determined to view these particular ideas, and that the custom or relation by which it is determined admits not of the least change, it forms them into a new system which it likewise dignifies with the title of realities. The first of these systems is the object of the memory and senses, the second of the judgment. It is this latter principle which peoples the world, and brings us acquainted with such existences as by their removal in time and place lie beyond the reach of the senses and memory. By means of it I paint the universe in my imagination and fix my attention on any part of it I please. I form an idea of Rome which I neither see nor remember, but which is connected with such impressions as I remember to have received from the conversation and books of travelers and historians. This idea of Rome I place in a certain situation on the idea of an object which I call the globe. I join to it the conception of a particular government and religion and manners. I look backward and consider its first foundation, its several revolutions, successes and misfortunes. All this and everything else which I believe are nothing but ideas, though by their force and settled order arising from custom and the relation of cause and effect they distinguish themselves from the other ideas which are merely the offspring of the imagination. As to the influence of contiguity and resemblance, we may observe that if the contiguous and resembling object be comprehended in this system of realities there is no doubt but these two relations will assist that of cause and effect and infix the related idea with more force in the imagination. This I shall enlarge upon presently. Meanwhile I shall carry my observation a step further and assert that even where the related object is but feigned, the relation will serve to enliven the idea and increase its influence. A poet, no doubt, will be the better able to form a strong description of the Elishan fields that he prompts his imagination by the view of a beautiful meadow or garden, as at another time he may by his fancy place himself in the midst of these fabulous regions that by the feigned contiguity he may enliven his imagination. But though I cannot altogether exclude the relations of resemblance and contiguity from operating on the fancy in this manner, it is observable that when single their influence is very feeble and uncertain. As the relation of cause and effect is requisite to persuade us of any real existence so is this persuasion requisite to give force to these other relations. For where upon the appearance of an impression we not only feign another object but likewise arbitrarily and of our mere good will and pleasure give it a particular relation to the impression, this can have but a small effect upon the mind, nor is there any reason why upon the return of the same impression we should be determined to place the same object in the same relation to it. There is no manner of necessity for the mind to feign any resembling and contiguous objects, and if it feigns such there is as little necessity for it always to confine itself to the same without any difference or variation. And indeed such a fiction is founded on so little reason that nothing but pure caprice can determine the mind to form it. And that principle being fluctuating and uncertain it is impossible it can ever operate with any considerable degree of force and constancy. The mind foresees and anticipates the change, and even from the very first instant feels the looseness of its actions and the weak hold it has of its objects. And as this imperfection is very sensible in every single instance, it still increases by experience and observation when we compare the several instances we may remember and form a general rule against the reposing any assurance in those momentary glimpses of light which arise in the imagination from a feigned resemblance and contiguity. The relation of cause and effect has all the opposite advantages. The objects it presents are fixed and unalterable. The impressions of the memory never change in any considerable degree, and each impression draws along with it a precise idea which takes its place in the imagination as something solid and real, certain and invariable. The thought is always determined to pass from the impression to the idea and from that particular impression to that particular idea without any choice or hesitation. But not content with removing this objection, I shall endeavor to extract from it a proof of the present doctrine. Contiguity and resemblance have an effect much inferior to causation, but still have some effect and augment the conviction of any opinion and the vivacity of any conception. If this can be proved in several new instances beside what we have already observed, it will be allowed no inconsiderable argument that belief is nothing but a lively idea related to a present impression. To begin with contiguity it has been remarked among the Mohammedans as well as Christians that those pilgrims who have seen Mecca or the Holy Land are ever after more faithful and zealous believers than those who have not had that advantage. A man whose memory presents him with a lively image of the Red Sea and the desert and Jerusalem and Galilee can never doubt of any miraculous events which are related either by Moses or the Evangelists. The lively idea of the places passes by an easy transition to the facts which are supposed to have been related to them by contiguity and increases the belief by increasing the vivacity of the conception. The remembrance of these fields and rivers has the same influence on the vulgar as a new argument and from the same causes. We may form a like observation concerning resemblance. We have remarked that the conclusion which we draw from a present object to its absent cause or effect is never founded on any qualities which we observe in that object considered in itself or in other words that it is impossible to determine otherwise than by experience what will result from any phenomenon or what has preceded it. But though this be so evident in itself that it seemed not to require any proof yet some philosophers have imagined that there is an apparent cause for the communication of motion and that a reasonable man might immediately infer the motion of one body from the impulse of another without having recourse to any past observation that this opinion is false will admit of an easy proof for if such an inference may be drawn merely from the ideas of body of motion and of impulse it must amount to a demonstration and must imply the absolute impossibility of any contrary supposition. Every effect then beside the communication of motion implies a formal contradiction and it is impossible not only that it can exist but also that it can be conceived. But we may soon satisfy ourselves of the contrary by forming a clear and consistent idea of one body's moving upon another and of its rest immediately upon the contact or of its returning back in the same line in which it came or of its annihilation or circular or elliptical motion and in short of an infinite number of other changes which we may suppose to undergo. These suppositions are all consistent and natural and the reason why we imagine the communication of motion to be more consistent and natural not only than those suppositions but also then any other natural effect is founded on the relation of resemblance betwixt the cause and effect which is here united to experience and binds the objects in the closest and most intimate manner to each other so as to make us imagine them to be absolutely inseparable. Resemblance then has the same or a parallel influence with experience and as the only immediate effect of experience is to associate our ideas together it follows that all belief arises from the association of ideas according to my hypothesis. It is universally allowed by the writers on optics that the eye at all times sees an equal number of physical points and that a man on the top of a mountain has no larger an image presented to his senses than when he is cooped up in the narrowest court or chamber. It is only by experience that he infers the greatness of the object from some peculiar qualities of the image and this inference of the judgment he confounds with sensation as is common on other occasions. Now it is evident that the inference of the judgment is here much more lively than what is usual in our common reasonings and that a man has a more vivid conception of the vast extent of the ocean from the image he receives by the eye when he stands on the top of the high promontory than merely from hearing the roaring of the waters. He feels a more sensible pleasure from its magnificence which is a proof of a more lively idea and he confounds his judgment with sensation which is another proof of it. But as the inference is equally certain and immediate in both cases this superior vivacity of our conception in one case can proceed from nothing but this that in drawing an inference from the site beside the customary conjunction there is also a resemblance betwixt the image and the object we infer which strengthens the relation and conveys the vivacity of the impression to the related idea with an easier and more natural movement. No weakness of human nature is more universal and conspicuous than what we commonly call credulity or a too easy faith in the testimony of others and this weakness is also very naturally accounted for from the influence of resemblance. When we receive any matter of fact upon human testimony our faith arises from the very same origin as our inferences from causes to effects and from effects to causes nor is there anything but our experience of the governing principles of human nature which can give us any assurance of the veracity of men. But though experience be the true standard of this as well as of all other judgments we seldom regulate ourselves entirely by it but have a remarkable propensity to believe whatever is reported even concerning apparitions enchantments and prodigies however contrary to daily experience and observation. The words or discourses of others have an intimate connection with certain ideas in their mind and these ideas have also a connection with the facts or objects which they represent. This latter connection is generally much overrated and commands our assent beyond what experience will justify which can proceed from nothing beside the resemblance betwixt the ideas and the facts. Other effects only point out their causes in an oblique manner but the testimony of men does it directly and is to be considered as an image as well as an effect. No wonder therefore we are so rash in drawing our inferences from it and are less guided by experience in our judgments concerning it than in those upon any other subject. 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 and 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 it is 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 it is 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 as 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 everywhere 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 their scarce are any who believe the immortality of the soul with a true and established judgment such as is derived from the testimony of travelers 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 people of that communion who do not blame the gunpowder treason and the massacre of saint 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 an 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 penetrated with the solidity of the subject nothing can be more disagreeable than fear and terror and it is only in dramatic performances and in religious discourses that they ever give pleasure in these latter cases the imagination reposes itself intolently 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 it is 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 it is 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 in fixes 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 it is certain it could never supply the place of that comparison nor produce any act of the mind which naturally belong to that principle a person that has lost a leg or an arm by amputation endeavors for a long time afterwards to serve himself with them after the death of anyone it is a common remark of the whole family but especially of 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 it will appear very convincing and the more so that it is founded on one of the most common phenomena that is anywhere 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 over balance 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 recognized by philosophers though in reality it be built almost on the same foundation of custom and repetition as our reasonings from causes and effects footnote seven in general we may observe that as our ascent to all probable reasonings is founded on the vivacity of ideas it resembles many of those whimsies and prejudices which are rejected under the appropriate character of being the offspring of the imagination by this expression it appears that the word imagination is commonly used in two different senses and though nothing be more contrary to true philosophy than this inaccuracy yet in the following reasonings I have often been obliged to fall into it when I oppose the imagination to the memory I mean the faculty by which we form our fainter ideas when I oppose it to reason I mean the same faculty excluding only our demonstrative and probable reasonings when I oppose it to neither it is indifferent whether it be taken in the larger or more limited sense or at least the context will sufficiently explain the meaning end of file 24 file 25 of a treatise of human nature volume one this LibriVox recording is in the public domain recording by George Yeager a treatise of human nature by David Hume book one part three section ten of the influence of belief but though education be disclaimed by philosophy as a fallacious ground of ascent 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 in impression to the actual feeling or only in idea as at present when I mentioned them it is 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 it is 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 everything 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 tranquility 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 and 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 favorable 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 a sense to every account of danger he meets with as a person of a sorrowful and melancholy disposition is very credulous of everything 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 it is 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 endeavor 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 invixes 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 shooing 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 it is 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 defections 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 vigor to the imagination but that a vigorous and strong imagination is of all talents the most proper to procure belief and authority it is difficult for us to withhold our ascent from what is painted out to us in all the colors 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 a mist 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 acquire 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 formally dignified with a 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 connections of the objects of these ideas but from the present temper and disposition of the person but how great so ever the pitch may be to which this vivacity rises it is 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 it is 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 are 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 arousing 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 fervors 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 colors 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 resemblance and differences betwixt a poetical enthusiasm and a serious conviction in the meantime i cannot forbear observing that the great difference in their feeling proceeds in some measure from reflection and general rules we observe that the vigor 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 it is thus the understanding corrects the appearances of the senses and makes us imagine that an object at 20 foot distance seems even to the eye as large as one of the same dimensions at 10 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 it is 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 end of file 25 file 26 of a treatise of human nature volume one this liber Vox recording is in the public domain recording by George Yeager a treatise of human nature by David Hume book one part three section 11 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 everyone 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 it is 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 it is only probable the sun will rise tomorrow or that all men must die though it is plain we have no further assurance of these facts than what experience affords us for this reason it 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 that is 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 it is this last species of reasoning I proceed to examine probability or reasoning from conjecture may be divided into two kinds that is 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 it is 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 it is 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 everyone that forms calculations concerning chances and here it is remarkable that though chance and causation be directly contrary yet it is 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 it is easy to arrive at a notion of a superior combination of chances a die 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 ascent neither by demonstration nor probability it is 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 it is impossible to prove with certainty that any event must fall on that side where 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 it is impossible to determine with certainty on which side the event will fall yet we can pronounce with certainty that it is more likely and probable it will 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 it is likely the event will fall on the side which is superior rather than on the inferior we do know 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 ascent since it appears that it is neither by arguments derived from demonstration nor from probability in order to clear up this difficulty we shall suppose a person to take a die 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 die into the box with an intention of throwing it it is 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 die to contemplate in order to comprehend one of the most curious operations of the understanding this die formed as above contains three circumstances worthy of our attention first certain causes such as gravity solidity a cubicle figure etc 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 die 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 it is 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 die 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 it is supposed that though the die 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 die 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 a like probable and possible the imagination passes from the cause that is the throwing of the die to the effect that is 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 die 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 it is 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 die that is 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 that is the figures inscribed on each side it is 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 where 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 it is evident that the impulses belonging to all these sides must reunite 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 it is 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 and of file 26 file 27 of a treatise of human nature by David Hume volume one this LibriVox recording is in the public domain recording by George Yeager book one part three section 12 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 it is 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 that is 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 it is 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 between these kinds of evidence is more easily perceived in the remote degrees than in the near and contiguous it is 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 it is 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 connection 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 forever follow from it and if this maximum be not always built upon as certain it is 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 contrarity in our experience and observation it would 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 it is 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 contrarity of events the first question that occurs on this head is concerning the nature and causes of the contrarity 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 it is at least possible the contrarity 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 further observation when they remark that upon an exact scrutiny a contrarity of effects always betrays a contrarity of causes and proceeds from their mutual hindrance 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 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 connection 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 contrarity of events their inferences from it are always of the same kind and founded on the same principles a contrarity 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 proportion 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 contrarity of past events we compare the different sides of the contrarity and carefully weigh the experiments which we have on each side once we may conclude that our reasonings of this kind arise not directly from the habit but in an oblique manner which we must now endeavor to explain it is 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 that is 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 contrarity 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 20 ships which go to see only 19 return suppose I see at present 20 ships that leave the port I transfer my past experience to the future and represent to myself 19 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 it is 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 then a mere fiction of the imagination but also then 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 colors 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 hear endeavor 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 everything 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 contrary of past experiments I shall propose the following considerations without fearing to give offense by that air of subtlety which attends them just reasoning ought still perhaps to retain its force however subtle 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 it would 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 contrary of experiments and it is evident an experiment in the past proves at least of 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 it is plain that when we transfer the past to the future the known to the unknown every past experiment has the same weight and that it is 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 maximum 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 connection 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 it is 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 it is impossible that in this particular there can be any difference nor is there anything 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 it is evident that as the contrary views are incompatible with each other and it is 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 comirical 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 it is obvious that in reasonings of this kind it is 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 contrarity of causes in the former where 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 it is 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 determinant object and as our belief however faint fixes itself on a determinant object it is 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 fall 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 it is 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 it is 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 it is 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 it were impossible the passion should increase by the increase of these parts thus a man who desires a thousand pound 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 two 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 that is 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 it is the constancy of the union which is diminished and in the probability derived from analogy it is the resemblance only which is affected without some degree of resemblance as well as union it is 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 it is evident it may still retain as much as may be the foundation of probability as long as there is any resemblance remaining end of file 27