Fourth experiment. Having found, that neither an object, without any relation of ideas 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 evident 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 chuse 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 immediately 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 sensation it causes resembles the sensation of the passion. That I may be sure I am not mistaken 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 to wheel 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 impressions 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 convinced of the influence of this relation, I try the effects of the other; and, by changing virtue for vice, convert the pleasant impression which arises from the former, into the disagreeable one which proceeds from the latter. The effect still answers expectation. Vice, when placed 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 suppose 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 completed 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 servitude. 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 through pride, love, hatred, humility, or through humility, hatred, love, pride, the experiment is not in the least diversified. Esteem and contempt, indeed, arise on some occasions instead of love and hatred; but these are, at the bottom, the same passions, only diversified by some causes, 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 different positions of which they are susceptible. Let us suppose, beside the relations above mentioned, 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 suppose, 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 required. The virtue of a brother must make me love him, as his vice or infamy must excite the contrary passion. But to judge only from the situation of affairs, I should not expect that the affections would rest there, and never transfuse themselves into any other impression. As there is here a person, who, by means of a double relation, is the object of my passion, the very same reasoning leads me to think the passion will be carried farther. The person has a relation of ideas to myself, according to the supposition; the passion of which he is the object, by being either agreeable or uneasy, has a relation of impressions to pride or humility. 'Tis evident, then, that one of these passions must arise from the love or hatred.

This is the reasoning I form in conformity to my hypothesis; and am pleased 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 in our relations; as nothing mortifies us more than their vice or infamy. This exact conformity of experience to our reasoning is a convincing proof of the solidity of that hypothesis upon which we reason.

Sixth experiment. This evidence will be still augmented if we reverse the experiment, and, preserving still the same relations, begin only with a different passion. Suppose that, instead of the virtue or vice of a son or brother, which causes first love or hatred, and afterwards pride or humility, we place these good or bad qualities on ourselves, without any immediate connexion with the person who is related to us, experience shows us, that, by this change of situation, the whole chain is broke, and that the mind is not conveyed from one passion to another, as in the preceding instance. We never love or hate a son or brother for the virtue or vice we discern in ourselves; though 'tis evident 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 esteemed contrary to my hypothesis, since the relations 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 should therefore be expected, that like causes must produce like effects, and a perfect transition arise from the double relation, as in all other cases. This difficulty we may easily solve by the following reflections.

'Tis evident that, as we are at all times intimately conscious of ourselves, our sentiments and passions, their ideas must strike upon us with greater vivacity than the ideas of the sentiments and passions of any other person. But every thing that strikes upon us with vivacity, and appears in a full and strong light, forces itself, in a manner, into our consideration, and becomes present to the mind on the smallest hint and most trivial relation. For the same reason, when it is once present, it engages the attention, and keeps it from wandering to other objects, however strong may be their relation to our first object. The imagination passes easily from obscure to lively ideas, but with difficulty from lively to obscure. In the one case the relation is aided by another principle; in the other case, 'tis opposed by it.

Now, I have observed, that those two faculties of the mind, the imagination and passions, assist each other in their operation when their propensities are similar, and when they act upon the same object. The mind has always a propensity to pass from a passion to any other related to it; and this propensity is forwarded when the object of the one passion is related to that of the other. The two impulses concur with each other, and render the whole transition more smooth and easy. But if it should happen, that, while the relation of ideas, strictly speaking, continues the same, its influence in causing a transition of the imagination should no longer take place, 'tis evident its influence on the passions must also cease, as being dependent entirely on that transition. This is the reason why pride or humility is not transfused into love or hatred with the same ease that the latter passions are changed into the former. If a person be my brother, I am his likewise: but though the relations be reciprocal, they have very different effects on the imagination. The passage is smooth and open from the consideration of any person related to us to that of ourself, of whom we are every moment conscious. But when the affections are once directed to ourself, the fancy passes not with the same facility from that object to any other person, how closely soever connected with us. This easy or difficult transition of the imagination operates upon the passions, and facilitates or retards their transition; which is a clear proof that these two faculties of the passions and imagination are connected together, and that the relations of ideas have an influence upon the affections. Besides innumerable experiments that prove this, we here find, that even when the relation remains; if by any particular circumstance its usual effect upon the fancy in producing an association or transition of ideas is prevented, its usual effect upon the passions, in conveying us from one to another, is in like manner prevented.

Some may, perhaps, find a contradiction betwixt this phenomenon and that of sympathy, where the mind passes easily from the idea of ourselves to that of any other object related to us. But this difficulty will vanish, if we consider that in sympathy our own person is not the object of any passion, nor is there any thing that fixes our attention on ourselves, as in the present case, where we are supposed to be actuated, with pride or humility. Ourself, independent of the perception of every other object, is in reality nothing; for which reason we must turn our view to external objects, and 'tis natural for us to consider with most attention such as lie contiguous to us, or resemble us. But when self is the object of a passion, 'tis not natural to quit the consideration of it till the passion be exhausted, in which case the double relations of impressions and ideas can no longer operate.

Seventh experiment. To put this whole reasoning to a farther trial, let us make a new experiment; and as we have already seen the effects of related passions and ideas, let us here suppose an identity of passions along with a relation of ideas; and let us consider the effects of this new situation. 'Tis evident a transition of the passions from the one object to the other is here in all reason to be expected; since the relation of ideas is supposed still to continue, and an identity of impressions must produce a stronger connexion, than the most perfect resemblance that can be imagined. If a double relation, therefore, of impressions and ideas, is able to produce a transition from one to the other, much more an identity of impressions with a relation of ideas. Accordingly, we find, that when we either love or hate any person, the passions seldom continue within their first bounds; but extend themselves towards all the contiguous objects, and comprehend the friends and relations of him we love or hate. Nothing is more natural than to bear a kindness to one brother on account of our friendship for another, without any farther examination of his character. A quarrel with one person gives us a hatred for the whole family, though entirely innocent of that which displeases us. Instances of this kind are every where to be met with.