SECT。1 Of the Object and Causes of Love and Hatred
It is altogether impossible to give any definition of the passions of love and hatred；and that because they produce merely a simple impression，without any mixture or com-position。It wou d be as unnecessary to attempt any description of them，drawn from their nature，origin，causes and objects；and that both because these are the subjects of our present enquiry，and because these passions of themselves are sufficiently known from our common feeling and experience。This we have already observ d concerning pride and humility，and here repeat it concerning love and hatred；and indeed there is so great a resemblance betwixt these two sets of passions，that we shall be oblig d to be-gin with a kind of abridgment of our reasonings concerning the former，in order to ex-plain the latter。
As the immediate object of pride and humility is self or that identical person，of whose thoughts，actions，and sensations we are intimately conscious；so the object of love and hatred is some other person，of whose thoughts，actions，and sensations we are not conscious。This is sufficiently evident from experience。Our love and hatred are al-ways directed to some sensible being external to us；and when we talk of self-love，tis not in a proper sense，nor has the sensation it produces any thing in common with that tender emotion which is excited by a friend or mistress。Tis the same case with hatred。We may be mortified by our own faults and follies；but never feel any anger or hatred。except from the injuries of others。
But tho the object of love and hatred be always some other person，tis plain that the object is not，properly speaking，the cause of these passions，or alone sufficient to excite them。For since love and hatred are directly contrary in their sensation，and have the same object in common，if that object were also their cause，it wou d produce theseopposite passions in an equal degree；and as they must，from the very first moment，de-stroy each other，none of them wou d ever be able to make its appearance。There must，therefore，be some cause different from the object。
If we consider the causes of love and hatred，we shall find they are very much diversify d，and have not many things in common。The virtue，knowledge，wit，good sense，good humour of any person，produce love and esteem；as the opposite qualities，hatred and contempt。The same passions arise from bodily accomplishments，such as beauty，force，swiftness，dexterity；and from their contraries；as likewise from the ex-ternal advantages and disadvantages of family，possession，cloaths，nation and climate。There is not one of these objects，but what by its different qualities may produce love and esteem，or hatred and contempt。
From the view of these causes we may derive a new distinction betwixt the quality that operates，and the subject on which it is plac d。A prince，that is possess d of a stately palace，commands the esteem of the people upon that account；and that first，by the beauty of the palace，and secondly，by the relation of property，which connects it with him。The removal of either of these destroys the passion；which evidently proves that the cause Is a compounded one。
It wou d be tedious to trace the passions of love and hatred，thro all the observa-tions which we have form d concerning pride and humility，and which are equally appli-cable to both sets of passions。It will be sufficient to remark in general，that the object of love and hatred is evidently some thinking person；and that the sensation of the former passion is always agreeable，and of the latter uneasy。We may also suppose with some shew of probability，that the cause of both these passions is always related to a thinking being，and that the cause of the former produce a separate pleasure，and of the latter a separate uneasiness。
One of these suppositions，viz。that the cause of love and hatred must be related to a person or thinking being，in order to produce these passions，is not only probable，but too evident to be contested。Virtue and vice，when consider d in the abstract；beauty and deformity，when plac d on inanimate objects；poverty and riches when belonging to a third person，excite no degree of love or hatred，esteem or contempt towards those，who have no relation to them。A person looking out at a window，sees me in the street，and beyond me-a beautiful palace，with which I have no concern：I believe none will pretend，that this person will pay me the same respect，as if I were owner of the palace。It is not so evident at first sight，that a relation of impressions is requisite to these passions，and that because in the transition the one impression is so much confounded with the other，that they become in a manner undistinguishable。But as in pride and hu-mility，we have easily been able to make the separation，and to prove，that every cause of these passions，produces a separate pain or pleasure，I might here observe the same method with the same success，in examining particularly the several causes of love and hatred。But as I hasten a full and decisive proof of these systems，I delay this examina-tion for a moment：And in the mean time shall endeavour to convert to my present pur-pose all my reaaonings concerning pride and humility，by an argument that isfounded on unquestionable experience。
There are few persons，that are satisfy d with their own character，or genius，or for-tune，who are nor desirous of shewing themselves to the world，and of acquiring the love and approbation of mankind。Now it is evident，that the very same qualities and circum-stances，which are the causes of pride or self-esteem，are also the causes of vanity or the desire of reputation；and that we always put to view those particulars with which in ourselves we are best satisfy d。But if love and esteem were not produc d by the same qualities as pride，according as these qualities are related to ourselves or others，this method of proceeding wou d be very absurd，nor cou d men expect a correspondence in the sentiments of every other person，with those themselves have entertain d。Tis true，few can form exact systems of the passions，or make reflections on their general nature and resemblances。But without such a progress in philosophy，we are not subject to many mistakes in this particular，but are sufficiently guided by common experience，as well as by a kind of presentation；which tells us what will operate on others，by what we feel immediately in ourselves。Since then the same qualities that produce pride or humil-ity，cause love or hatred；all the arguments that have been employ d to prove，that the causes of the former passions excite a pain or pleasure independent of the passion，will be applicable with equal evidence to the causes of the latter。
SECT。2 Experiences to Confirm This System
Upon duly weighing these arguments，no one will make any scruple to assent to that conccusion I draw from them，concerning the transition along related impressions and i-deas，especially as tis a principle，in itself，so easy and natural。But that we may place this system beyond doubt both with regard to love and hatred，pride and humility，it will be proper to make some new experiments upon all these passions，as well as to recal a few of these observations，which I have formerly touch d upon。
In order to make these experiments，let us suppose I am m company with a person，whom I formerly regarded without any sentiments either of friendship or enmity。Here I have the natural and ultimate object of all these four pas sions plac d before me。Myself am the proper object of pride or humility；the other person of love or hatred。
Regard now with attention the nature of these passions，and their situation with re-spect to each other。Tis evident here are four affections，plac d，as it were，in a square or regular connexion with，and distance from each other。The passions of pride and hu-mility，as well as those of love and hatred，are connected together by the identity of their object，which to the first set of passions is self，to the second some other person。These two lines of communication or connexion form two opposite sides of the square。A-gain，pride and love are agreeable passions；hatred and humility uneasy。This similitude of sensation betwixt pride and love，and that betwixt humility and hatred form a new connexion，and may be consider d as the other two sides of the square。Upon the whole，pride is connected with humility，love with hatred，by their objects or ideas：Pride with love，humility with hatred，by their sensations or impressions。
I say then，that nothing can produce any of these passions without bearing it a double relation，viz。of ideas to the object of the passion，and of sensation to the pas-sion itself。This we must prove by our experiments。
First Experiment。To proceed with the greater order in these experiments，let us first suppose，that being plac d in the situation above-mentioned，viz。in company with some other person，there is an object presented，that has no relation either of impres-sions or ideas to any of these passions。Thus suppose we regard together an ordinary stone，or other common object，belonging to neither of us，and causing of itself no emo-tion，or independent pain and pleasure：Tis evident such an object will produce none of these four passions。Let us try it upon each of them successively。Let us apply it to love，to hatred，to humility，to pride；none of them ever arises in the smallest degree i-maginable。Let us change the object，as oft as we please；provided still we choose one，that has neither of these two relations。Let us repeat the experiment in all the disposi-tions，of which the mind is susceptible。No object，in the vast variety of nature，will，in any disposition，produce any passion without these relations。
Second Experiment。Since an object，that wants both these relations can never-produce any passion，let us bestow on it only one of these relations；and see what will follow。Thus suppose，I regard a stone or any common object，that belongs either to me or my companion，and by that means acquires a relation of ideas to the object of the pas-sions：Tis plain，that to consider the matter a priori，no emotion of any kind can rea-sonably be expected。For besides，that a relation of ideas operates secretly and calmly on the mind，it bestows an equal impulse towards the opposite passions of pride and hu-mility，love and hatred，according as the object belongs to ourselves or others；which opposition of the passions must destroy both，and leave the mind perfectly free from any affection or emotion。This reasoning a priori is confirm d by experience。No trivial or vulgar object，that causes not a pain or pleasure，independent of the passion，will ever，by its property or other relations，either to ourselves or others，be able to produce the af-fections of pride or humility，love or hatred。
Third Experiment。Tis evident，therefore，that a relation of ideas is not able alone to give rise to these affections。Let us now remove this relation，and in its stead place a relation of impressions，by presenting an object，which is agreeable or disagreeable，but has no relation either to ourself or companion；and let us observe the consequences。To consider the matter first a priori，as in the preceding experiment；we may conclude，that the object will have a small，but an uncertain connexion with these passions。For be-sides，that this relation is not a cold and imperceptible one，it has not the inconvenience of the relation of ideas，nor directs us with equal force to two contrary passions，which by their opposition destroy each other。But if we consider，on the other hand，that this transition from the sensation to the affection is not forwarded by any principle，that pro-duces a transition of ideas；but，on the contrary，that tho the one impression be easily transfus d into the other，yet the change of objects is suppos d contrary to all the princi-ples，that cause a transition of that kind；we may from thence infer，that nothing will ever be a steady or durable cause of any passion，that is connected with the passion merely by a relation of impressions。What our reason wou d conclude from analogy，after balancing these arguments，wou d be，that an object，which produces pleasure or uneas-iness，but has no manner of connexion either with ourselves or others，may give such a turn to the disposition，as that may naturally fall into pride or love，humility or hatred，and search for other objects，upon which by a double relation，it can found these affec-tions；but that an object，which has only one of these relations，tho the most advanta-geous one，can never give rise to any constant and establish d passion。
Most fortunately all this reasoning is found to be exactly conformable to experience，and the phenomena of the passions。Suppose I were travelling with a companion thro a country，to which we are both utter strangers；tis evident，that if the prospects be beau-tiful，the roads agreeable，and the inns commodious，this may put me into good humour both with myself and fellow-traveller。But as we suppose，that this country has no rela-tion either to myself or friend。it can never be the immediate cause of pride or love；and therefore if I found not the passion on some other object，that bears either of us a closer relation，my emotions are rather to be considerd as the overflowings of an elevate or hu-mane disposition，than as an establish d passion。The case is the same where the object produces uneasiness。
Fourth Experiment。Having found，that neither an object without any relation of i-deas or impressions，nor an object，that has only one relation，can ever cause pride or humility，love or hatred；reason alone may convince us，without any farther experiment，that whatever has a double relation must necessarily excite these passions；since tis evi-dent they must have some cause。But to leave as little room for doubt as possible，let us renew our experiments，and see whether the event in this case answers our expectation。I choose an object，such as virtue，that causes a separate satisfaction：On this object I bestow a relation to self；and find，that from this disposition of affairs，there immediate-ly arises a passion。But what passion？That very one of pride，to which this object bears a double relation。Its idea is related to that of self，the object of the passion：The sensa-tion it causes resembles the sensation of the passion。That I may be sure I am not mis-taken in this experiment，I remove first one relation；then another；and find，that each removal destroys the passion，and leaves the object perfectly indifferent。But I am not content with this。I make a still farther trial；and instead of removing the relation，I only change it for one of a different kind。I suppose the virtue to belong to my companion，not to myself；and observe what follows from this alteration。I immediately perceive the affections wheel to about，and leaving pride，where there is only one relation，viz。of impressions，fall to the side of love，where they are attracted by a double relation of im-pressions and ideas。By repeating the same experiment，in changing anew the relation of ideas，I bring the affections back to pride；and by a new repetition I again place them at love or kindness。Being fully convinc d of the influence of this relation，I try the effects of the other；and by changing virtue for vice，convert the pleasant impression，which a-rises from the former，into the disagreeable one，which proceeds from the latter。The effect still answers expectation。Vice，when plac d on another，excites，by means of its double relations，the passion of hatred，instead of love，which for the same reason arises from virtue。To continue the experiment，I change anew the relation of ideas，and sup-pose the vice to belong to myself。What follows？What is usual。A subsequent change of the passion from hatred to humility。This humility I convert into pride by a new change of the impression；and find after all that I have compleated the round，and have by these changes brought back the passion to that very situation，in which I first found it。
But to make the matter still more certain，I alter the object；and instead of vice and virtue，make the trial upon beauty and deformity，riches and poverty，power and servi-tude。Each of these objects runs the circle of the passions in the same manner，by a change of their relations：And in whatever order we proceed，whether thro pride，love，hatred，humility，or thro humility，hatred，love，pride，the experiment is not in the least diversify d。Esteem and contempt，indeed，arise on some occasions instead of love and hatred；but these are at the bottom the same passions，only diversify d by some cau-ses，which we shall explain afterwards。
Fifth Experiment。To give greater authority to these experiments，let us change the situation of affairs as much as possible，and place the passions and objects in all the dif-ferent positions，of which they are susceptible。Let us suppose，beside the relations a-bove-mention d，that the person，along with whom I make all these experiments，is closely connected with me either by blood or friendship。He is，we shall suppose，my son or brother，or is united to me by a long and familiar acquaintance。Let us next sup-pose，that the cause of the passion acquires a double relation of impressions and ideas to this person；and let us see what the effects are of all these complicated attractions and relations。
Before we consider what they are in fact，let us determine what they ought to be，conformable to my hypothesis。Tis plain，that，according as the impression is either pleasant or uneasy，the passion of love or hatred must arise towards the person，who is thus connected to the cause of the impression by these double relations，which I have all along requir d。
This is the reasoning I form in conformity to my hypothesis；and am pleas d to find upon trial that every thing answers exactly to my expectation。The virtue or vice of a son or brother not only excites love or hatred，but by a new transition，from similar causes，gives rise to pride or humility。Nothing causes greater vanity than any shining quality inour relations；as nothing mortifies us more than their vice or infamy。This exact con-formity of experience to our reasoning is a convincing proof of the solidity of that hypoth-esis，upon which we reason。
Sixth Experiment。This evidence will be still augmented，if we reverse the experi-ment，and preserving still the same relations，begin only with a different passion。Sup-pose，that instead of the virtue or vice of a son or brother，which causes first love or ha-tred，and afterwards pride or humility，we place these good or bad qualities on our-selves，without any immediate connexion with the person，who is related to us：Experi-ence shews us，that by this change of situation the whole chain is broke，and that the mind is not convey d from one passion to another，as in the preceding instance。We nev-er love or hate a son or brother for the virtue or vice we discern in ourselves；tho it evi-dent the same qualities in him give us a very sensible pride or humility。The transition from pride or humility to love or hatred is not so natural as from love or hatred to pride or humility。This may at first sight be esteem d contrary to my hypothesis；since the rela-tions of impressions and ideas are in both cases precisely the same。Pride and humility are impressions related to love and hatred。Myself am related to the person。It shou d，therefore，be expected，that like causes must produce like effects，and a perfect transi-tion arise from the double relation，as in all other cases。This difficulty we may easily solve by the following reflections。