generation to another, from the remotest ancestors to their posterity, who are both their heirs and their descendants. By this facility the impression is transmitted more entire, and excites a greater degree of pride and vanity.
The case is the same with the transmission of the honours and fortune through a succession of males without their passing through any female.
'Tis a quality of human nature, which we shall consider afterwards,[3] that the imagination naturally turns to whatever is important and considerable; and where two objects are presented to it, a small and a great one, usually leaves the former, and dwells entirely upon the latter. As in the society of marriage, the male sex has the advantage above the female, the husband first engages our attention; and whether we consider him directly, or reach him by passing through related objects, the thought both rests upon him with greater satisfaction, and arrives at him with greater facility than his consort. 'Tis easy to see, that this property must strengthen the child's relation to the father, and weaken that to the mother. For as all relations are nothing but a propensity to pass from one idea to another, whatever strengthens the propensity strengthens the relation; and as we have a stronger propensity to pass from the idea of the children to that of the father, than from the same idea to that of the mother, we ought to regard the former relation as the closer and more considerable. This is the reason why children commonly bear their father's name, and are esteemed to be of nobler or baser birth, according to _his_ family. And though the mother should be possessed of a superior spirit and genius to the father, as often happens, the _general rule_ prevails, notwithstanding the exception, according to the doctrine above explained. Nay, even when a superiority of any kind is so great, or when any other reasons have such an effect, as to make the children rather represent the mother's family than the father's, the general rule still retains such an efficacy, that it weakens the relation, and makes a kind of break in the line of ancestors. The imagination runs not along them with facility, nor is able to transfer the honour and credit of the ancestors to their posterity of the same name and family so readily, as when the transition is conformable to the general rules, and passes from father to son, or from brother to brother.
[3] Part II. Sect. 2.
SECTION X.
OF PROPERTY AND RICHES.
But the relation which is esteemed the closest, and which, of all others, produces most commonly the passion of pride, is that of _property_. This relation 'twill be impossible for me fully to explain before I come to treat of justice and the other moral virtues. 'Tis sufficient to observe on this occasion, that property may be defined, _such a relation betwixt a person and an object as permits him, but forbids any other, the free use and possession of it, without violating the laws of justice and moral equity_. If justice therefore be a virtue, which has a natural and original influence on the human mind, property may be looked upon as a particular species of _causation_; whether we consider the liberty it gives the proprietor to operate as he pleases upon the object, or the advantages which he reaps from it. 'Tis the same case, if justice, according to the system of certain philosophers, should be esteemed an artificial and not a natural virtue. For then honour, and custom, and civil laws supply the place of natural conscience, and produce in some degree, the same effects. This, in the mean time, is certain, that the mention of the property naturally carries our thought to the proprietor, and of the proprietor to the property; which being a proof of a perfect relation of ideas, is all that is requisite to our present purpose. A relation of ideas, joined to that of impressions, always produces a transition of affections; and therefore, whenever any pleasure or pain arises from an object, connected with us by property, we may be certain, that either pride or humility must arise from this conjunction of relations, if the foregoing system be solid and satisfactory. And whether it be so or not, we may soon satisfy ourselves by the most cursory view of human life.
Every thing belonging to a vain man is the best that is any where to be found. His houses, equipage, furniture, clothes, horses, hounds, excel all others in his conceit; and 'tis easy to observe, that from the least advantage in any of these, he draws a new subject of pride and vanity. His wine, if you'll believe him, has a finer flavour than any other; his cookery is more exquisite; his table more orderly; his servant more expert; the air in which he lives more healthful; the soil he cultivates more fertile; his fruits ripen earlier, and to greater perfection; such a thing is remarkable for its novelty; such another for its antiquity: this is the workmanship of a famous artist, that belonged to such a prince or great man; all objects, in a word, that are useful, beautiful, or surprising, or are related to such, may, by means of property, give rise to this passion. These agree in giving pleasure, and agree in nothing else. This alone is common to them, and therefore must be the quality that produces the passion, which is their common effect. As every new instance is a new argument, and as the instances are here without number, I may venture to affirm, that scarce any system was ever so fully proved by experience, as that which I have here advanced.
If the property of any thing that gives pleasure either by its utility, beauty, or novelty, produces also pride by a double relation of impressions and ideas; we need not be surprised that the power of acquiring this property should have the same effect. Now, riches are to be considered as the power of acquiring the property of what pleases; and 'tis only in this view they have any influence on the passions.
Paper will, on many occasions, be considered as riches, and that because it may convey the power of acquiring money; and money is not riches, as it is a metal endowed with certain qualities of solidity, weight, and fusibility; but only as it has a relation to the pleasures and conveniences of life. Taking then this for granted, which is in itself so evident, we may draw from it one of the strongest arguments I have yet employed to prove the influence of the double relations on pride and humility.
It has been observed, in treating of the understanding, that the distinction which we sometimes make betwixt a _power_ and the _exercise_ of it, is entirely frivolous, and that neither man nor any other being ought ever to be thought possessed of any ability, unless it be exerted and put in action. But though this be strictly true in a just and _philosophical_ way of thinking, 'tis certain it is not _the philosophy_ of our passions, but that many things operate upon them by means of the idea and supposition of power, independent of its actual exercise. We are pleased when we acquire an ability of procuring pleasure, and are displeased when another acquires a power of giving pain. This is evident from experience; but in order to give a just explication of the matter, and account for this satisfaction and uneasiness, we must weigh the following reflections.
'Tis evident the error of distinguishing power from its exercise proceeds not entirely from the scholastic doctrine of _free will_, which, indeed, enters very little into common life, and has but small influence on our vulgar and popular ways of thinking. According to that doctrine, motives deprive us not of free-will, nor take away our power of performing or forbearing any action. But according to common notions a man has no power, where very considerable motives lie betwixt him and the satisfaction of his desires, and determine him to forbear what he wishes to perform. I do not think I have fallen into my enemy's power when I see him pass me in the streets with a sword by his side, while I am, unprovided of any weapon. I know that the fear of the civil magistrate is as strong a restraint as any of iron, and that I am in as perfect safety as if he were chained or imprisoned. But when a person acquires such an authority over me, that not only there is no external obstacle to his actions, but also that he may punish or reward me as he pleases without any dread of punishment in his turn, I then attribute a full power to him, and consider myself as his subject or vassal.
Now, if we compare these two cases, that of a person who has very strong motives of interest or safety to forbear any action, and that of another who lies under no such obligation, we shall find, according to the philosophy explained in the foregoing book, that the only _known_ difference betwixt them lies in this, that in the former case we conclude, from _past experience_, that the person never will perform that action, and in the latter, that he possibly or probably will perform it. Nothing is more fluctuating and inconstant on many occasions than the will of man; nor is there any thing but strong motives which can give us an absolute certainty in pronouncing concerning any of his future actions. When we see a person free from these motives, we suppose a possibility either of his acting or forbearing; and though, in general, we may conclude him to be determined by motives and causes, yet this removes not the uncertainty of our judgment concerning these causes, nor the influence of that uncertainty on the passions. Since, therefore, we ascribe a power of performing an action to every one who has no very powerful motive to forbear it, and refuse it to such as have, it may justly be concluded, that _power_ has always a reference to its _exercise_, either actual or probable, and that we consider a person as endowed with any ability when we find, from past experience, that 'tis probable, or at least possible, he may exert it. And indeed, as our passions always regard the real existence of objects, and we always judge of this reality from past instances, nothing can be more likely of itself, without any farther reasoning, than that power consists in the possibility or probability of any action, as discovered by experience and the practice of the world.
Now, 'tis evident that, wherever a person is in such a situation with regard to me that there is no very powerful motive to deter him from injuring me, and consequently 'tis _uncertain_ whether he will injure me or not, I must be uneasy in such a situation, and cannot consider the possibility or probability of that injury without a sensible concern. The passions are not only affected by such events as are certain and infallible, but also in an inferior degree by such as are possible and contingent. And though perhaps I never really feel any harm, and discover by the event, that, philosophically speaking, the person never had any power of harming me, since he did not exert any, this prevents not my uneasiness from the preceding uncertainty. The agreeable passions may here operate as well as the uneasy, and convey a pleasure when I perceive a good to become either possible or probable by the possibility or probability of another's bestowing it on me, upon the removal of any strong motives which might formerly have hindered him.
But we may farther observe, that this satisfaction increases, when any good approaches, in such a manner that it is in one's _own_ power to take or leave it, and there neither is any physical impediment, nor any very strong motive to hinder our enjoyment. As all men desire pleasure, nothing can be more probable than its existence when there is no external obstacle to the producing it, and men perceive no danger in following their inclinations. In that case their imagination easily anticipates the satisfaction, and conveys the same joy as if they were persuaded of its real and actual existence.
But this accounts not sufficiently for the satisfaction which attends riches. A miser receives delight from his money; that is, from the _power_ it affords him of procuring all the pleasures and conveniences of life, though he knows he has enjoyed his riches for forty years without ever enjoying them; and consequently cannot conclude, by any species of reasoning, that the real existence of these pleasures is nearer, than if he were entirely deprived of all his possessions.
But though he cannot form any such conclusion in a way of reasoning concerning the nearer approach of the pleasure, 'tis certain he _imagines_ it to approach nearer, whenever all external obstacles are removed, along with the more powerful motives of interest and danger, which oppose it. For farther satisfaction on this head, I must refer to my account of the will,[4] where I shall explain that false sensation of liberty, which makes us imagine we can perform any thing that is not very dangerous or destructive. Whenever any other person is under no strong obligations of interest to forbear any pleasure, we judge from _experience_, that the pleasure will exist, and that he will probably obtain it. But when ourselves are in that situation, we judge from an _illusion of the fancy_, that the pleasure is still closer and more immediate. The will seems to move easily every way, and casts a shadow or image of itself even to that side on which it did not settle. By means of this image the enjoyment seems to approach nearer to us, and gives us the same lively satisfaction as if it were perfectly certain and unavoidable.
'Twill now be easy to draw this whole reasoning to a point, and to prove, that when riches produce any pride or vanity in their possessors, as they never fail to do, 'tis only by means of a double relation of impressions and ideas. The very essence of riches consists in the power of procuring the pleasures and conveniences of life.
The very essence of this power consists in the probability of its exercise, and in its causing us to anticipate, by a _true_ or _false_ reasoning, the real existence of the pleasure. This anticipation of pleasure is, in itself, a very considerable pleasure; and as its cause is some possession or property which we enjoy, and which is thereby related to us, we here clearly see all the parts of the foregoing system most exactly and distinctly drawn out before us.
For the same reason, that riches cause pleasure and pride, and poverty excites uneasiness and humility, power must produce the former emotions, and slavery the latter. Power or an authority over others makes us capable of satisfying all our desires; as slavery, by subjecting us to the will of others, exposes us to a thousand wants and mortifications.
'Tis here worth observing, that the vanity of power, or shame of slavery, are much augmented by the consideration of the persons over whom we exercise our authority, or who exercise it over us. For, supposing it possible to frame statues of such an admirable mechanism, that they could move and act in obedience to the will; 'tis evident the possession of them would give pleasure and pride, but not to such a degree as the same authority, when exerted over sensible and rational creatures, whose condition, being compared to our own, makes it seem more agreeable and honourable. Comparison is in every case a sure method of augmenting our esteem of any thing. A rich man feels the felicity of his condition better by opposing it to that of a beggar.
But there is a peculiar advantage in power, by the contrast, which is, in a manner, presented to us betwixt ourselves and the person we command. The comparison is obvious and natural: the imagination finds it in the very subject: the passage of the thought to its conception is smooth and easy. And that this circumstance has a considerable effect in augmenting its influence, will appear afterwards in examining the nature of _malice_ and _envy_.
[4] Part III. Sect. 2.
SECTION XI.
OF THE LOVE OF FAME.
But beside these original causes of pride and humility, there is a secondary one in the opinions of others, which has an equal influence on the affections. Our reputation, our character, our name, are considerations of vast weight and importance; and even the other causes of pride, virtue, beauty and riches, have little influence, when not seconded by the opinions and sentiments of others. In order to account for this phenomenon, 'twill be necessary to take some compass, and first explain the nature of _sympathy_.
No quality of human nature is more remarkable, both in itself and in its consequences, than that propensity we have to sympathize with others, and to receive by communication their inclinations and sentiments, however different from, or even contrary to, our own. This is not only conspicuous in children, who implicitly embrace every opinion proposed to them; but also in men of the greatest judgment and understanding, who find it very difficult to follow their own reason or inclination, in opposition to that of their friends and daily companions. To this principle we ought to ascribe the great uniformity we may observe in the humours and turn of thinking of those of the same nation; and 'tis much more probable, that this resemblance arises from sympathy, than from any influence of the soil and climate, which, though they continue invariably the same, are not able to preserve the character of a nation the same for a century together. A good-natured man finds himself in an instant of the same humour with his company; and even the proudest and most surly take a tincture from their countrymen and acquaintance. A cheerful countenance infuses a sensible complacency and serenity into my mind; as an angry or sorrowful one throws a sudden damp upon me. Hatred, resentment, esteem, love, courage, mirth and melancholy; all these passions I feel more from communication, than from my own natural temper and disposition. So remarkable a phenomenon merits our attention, and must be traced up to its first principles.
When any affection is infused by sympathy, it is at first known only by its effects, and by those external signs in the countenance and conversation, which convey an idea of it. This idea is presently converted into an impression, and acquires such a degree of force and vivacity, as to become the very passion itself, and produce an equal emotion as any original affection. However instantaneous this change of the idea into an impression may be, it proceeds from certain views and reflections, which will not escape the strict scrutiny of a philosopher, though they may the person himself who makes them.
'Tis evident that the idea, or rather impression of ourselves, is always intimately present with us, and that our consciousness gives us so lively a conception of our own person, that 'tis not possible to imagine that any thing can in this particular go beyond it. Whatever object, therefore, is related to ourselves, must be conceived with a like vivacity of conception, according to the foregoing principles; and though this relation should not be so strong as that of causation, it must still have a considerable influence. Resemblance and contiguity are relations not to be neglected; especially when, by an inference from cause and effect, and by the observation of external signs, we are informed of the real existence of the object, which is resembling or contiguous.
Now, 'tis obvious that nature has preserved a great resemblance among all human creatures, and that we never remark any passion or principle in others, of which, in some degree or other, we may not find a parallel in ourselves. The case is the same with the fabric of the mind as with that of the body. However the parts may differ in shape or size, their structure and composition are in general the same.
There is a very remarkable resemblance, which preserves itself amidst all their variety; and this resemblance must very much contribute to make us enter into the sentiments of others, and embrace them with facility and pleasure. Accordingly we find, that where, beside the general resemblance of our natures, there is any peculiar similarity in our manners, or character, or country, or language, it facilitates the sympathy. The stronger the relation is betwixt ourselves and any object, the more easily does the imagination make the transition, and convey to the related idea the vivacity of conception, with which we always form the idea of our own person.
Nor is resemblance the only relation which has this effect, but receives new force from other relations that may accompany it. The sentiments of others have little influence when far removed from us, and require the relation of contiguity to make them communicate themselves entirely. The relations of blood, being a species of causation, may sometimes contribute to the same effect; as also acquaintance, which operates in the same manner with education and custom, as we shall see more fully afterwards.[5] All these relations, when united together, convey the impression or consciousness of our own person to the idea of the sentiments or passions of others, and makes us conceive them in the strongest and most lively manner.
It has been remarked in the beginning of this Treatise, that all ideas are borrowed from impressions, and that these two kinds of perceptions differ only in the degrees of force and vivacity with which they strike upon the soul. The component parts of ideas and impressions are precisely alike. The manner and order of their appearance may be the same. The different degrees of their force and vivacity are, therefore, the only particulars that distinguish them: and as this difference may be removed, in some measure, by a relation betwixt the impressions and ideas, 'tis no wonder an idea of a sentiment or passion may by this means be so enlivened as to become the very sentiment or passion.
The lively idea of any object always approaches its impression; and 'tis certain we may feel sickness and pain from the mere force of imagination, and make a malady real by often thinking of it. But this is most remarkable in the opinions and affections; and 'tis there principally that a lively idea is converted into an impression. Our affections depend more upon ourselves, and the internal operations of the mind, than any other impressions; for which reason they arise more naturally from the imagination, and from every lively idea we form of them. This is the nature and cause of sympathy; and 'tis after this manner we enter so deep into the opinions and affections of others, whenever we discover them.
What is principally remarkable in this whole affair, is the strong confirmation these phenomena give to the foregoing system concerning the understanding, and consequently to the present one concerning the passions, since these are analogous to each other. 'Tis indeed evident, that when we sympathize with the passions and sentiments of others, these movements appear at first in _our_ mind as mere ideas, and are conceived to belong to another person, as we conceive any other matter of fact. 'Tis also evident, that the ideas of the affections of others are converted into the very impressions they represent, and that the passions arise in conformity to the images we form of them. All this is an object of the plainest experience, and depends not on any hypothesis of philosophy. That science can only be admitted to explain the phenomena; though at the same time it must be confessed, they are so clear of themselves, that there is but little occasion to employ it. For, besides the relation of cause and effect, by which we are convinced of the reality of the passion with which we sympathize; besides this, I say, we must be assisted by the relations of resemblance and contiguity, in order to feel the sympathy in its full perfection. And since these relations can entirely convert an idea into an impression, and convey the vivacity of the latter into the former, so perfectly as to lose nothing of it in the transition, we may easily conceive how the relation of cause and effect alone, may serve to strengthen and enliven an idea. In sympathy there is an evident conversion of an idea into an impression. This conversion arises from the relation of objects to ourself. Ourself is always intimately present to us. Let us compare all these circumstances, and we shall find, that sympathy is exactly correspondent to the operations of our understanding; and even contains something more surprising and extraordinary.
'Tis now time to turn our view from the general consideration of sympathy, to its influence on pride and humility, when these passions arise from praise and blame, from reputation and infamy. We may observe, that no person is ever praised by another for any quality which would not, if real, produce of itself a pride in the person possessed of it. The eulogiums either turn upon his power, or riches, or family, or virtue; all of which are subjects of vanity, that we have already explained and accounted for. 'Tis certain, then, that if a person considered himself in the same light in which he appears to his admirer, he would first receive a separate pleasure, and afterwards a pride or self-satisfaction, according to the hypothesis above explained. Now, nothing is more natural than for us to embrace the opinions of others in this particular, both from _sympathy_, which renders all their sentiments intimately present to us, and from _reasoning_, which makes us regard their judgment as a kind of argument for what they affirm. These two principles of authority and sympathy influence almost all our opinions, but must have a peculiar influence when we judge of our own worth and character. Such judgments are always attended with passion;[6] and nothing tends more to disturb our understanding, and precipitate us into any opinions, however unreasonable, than their connexion with passion, which diffuses itself over the imagination, and gives an additional force to every related idea. To which we may add, that, being conscious of great partiality in our own favour, we are peculiarly pleased with any thing that confirms the good opinion we have of ourselves, and are easily shocked with whatever opposes it.
All this appears very probable in theory; but in order to bestow a full certainty on this reasoning, we must examine the phenomena of the passions, and see if they agree with it.
Among these phenomena we may esteem it a very favourable one to our present purpose, that though fame in general be agreeable, yet we receive a much greater satisfaction from the approbation of those whom we ourselves esteem and approve of, than of those whom we hate and despise. In like manner we are principally mortified with the contempt of persons upon whose judgment we set some value, and are, in a great measure, indifferent about the opinions of the rest of mankind. But if the mind received from any original instinct a desire of fame, and aversion to infamy, fame and infamy would influence us without distinction; and every opinion, according as it were favourable or unfavourable, would equally excite that desire or aversion. The judgment of a fool is the judgment of another person, as well as that of a wise man, and is only inferior in its influence on our own judgment.
We are not only better pleased with the approbation of a wise man than with that of a fool, but receive an additional satisfaction from the former, when 'tis obtained after a long and intimate acquaintance. This is accounted for after the same manner.
The praises of others never give us much pleasure, unless they concur with our own opinion, and extol us for those qualities in which we chiefly excel. A mere soldier little values the character of eloquence; a gownman, of courage; a bishop, of humour; or a merchant, of learning. Whatever esteem a man may have for any quality, abstractedly considered, when he is conscious he is not possessed of it, the opinions of the whole world will give him little pleasure in that particular, and that because they never will be able to draw his own opinion after them.
Nothing is more usual than for men of good families, but narrow circumstances, to leave their friends and country, and rather seek their livelihood by mean and mechanical employments among strangers, than among those who are acquainted with their birth and education.
We shall be unknown, say they, where we go. Nobody will suspect from what family we are sprung. We shall be removed from all our friends and acquaintance, and our poverty and meanness will by that means sit more easy upon us. In examining these sentiments, I find they afford many very convincing arguments for my present purpose.
First, we may infer from them that the uneasiness of being contemned depends on sympathy, and that sympathy depends on the relation of objects to ourselves, since we are most uneasy under the contempt of persons who are both related to us by blood and contiguous in place.
Hence we seek to diminish this sympathy and uneasiness by separating these relations, and placing ourselves in a contiguity to strangers, and at a distance from relations.
Secondly, we may conclude, that relations are requisite to sympathy, not absolutely considered as relations, but by their influence in converting our ideas of the sentiments of others into the very sentiments by means of the association betwixt the idea of their persons and that of our own. For here the relations of kindred and contiguity both subsist, but not being united in the same persons, they contribute in a less degree to the sympathy.
Thirdly, this very circumstance of the diminution of sympathy, by the separation of relations, is worthy of our attention. Suppose I am placed in a poor condition among strangers, and consequently am but lightly treated; I yet find myself easier in that situation, than when I was every day exposed to the contempt of my kindred and countrymen.
Here I feel a double contempt; from my relations, but they are absent; from those about me, but they are strangers. This double contempt is likewise strengthened by the two relations of kindred and contiguity.
But as the persons are not the same who are connected with me by those two relations, this difference of ideas separates the impressions arising from the contempt, and keeps them from running into each other.
The contempt of my neighbours has a certain influence, as has also that of my kindred; but these influences are distinct and never unite, as when the contempt proceeds from persons who are at once both my neighbours and kindred. This phenomenon is analogous to the system of pride and humility above explained, which may seem so extraordinary to vulgar apprehensions.
Fourthly, a person in these circumstances naturally conceals his birth from those among whom he lives, and is very uneasy if any one suspects him to be of a family much superior to his present fortune and way of living. Every thing in this world is judged of by comparison What is an immense fortune for a private gentleman, is beggary for a prince.
A peasant would think himself happy in what cannot afford necessaries for a gentleman. When a man has either been accustomed to a more splendid way of living, or thinks himself entitled to it by his birth and quality, every thing below is disagreeable and even shameful; and 'tis with the greatest industry he conceals his pretensions to a better fortune. Here he himself knows his misfortunes; but as those with whom he lives are ignorant of them, he has the disagreeable reflection and comparison suggested only by his own thoughts, and never receives it by a sympathy with others; which must contribute very much to his ease and satisfaction.
If there be any objections to this hypothesis, _that the pleasure which we receive from praise arises from a communication of sentiments_, we shall find, upon examination, that these objections, when taken in a proper light, will serve to confirm it. Popular fame may be agreeable even to a man who despises the vulgar; but 'tis because their multitude gives them additional weight and authority. Plagiaries are delighted with praises, which they are conscious they do not deserve; but this is a kind of castle-building, where the imagination amuses itself with its own fictions, and strives to render them firm and stable by a sympathy with the sentiments of others. Proud men are most shocked with contempt, though they do not most readily assent to it; but 'tis because of the opposition betwixt the passion, which is natural to them, and that received by sympathy. A violent lover, in like manner, is very much displeased when you blame and condemn his love; though 'tis evident your opposition can have no influence but by the hold it takes of himself, and by his sympathy with you. If he despises you, or perceives you are in jest, whatever you say has no effect upon him.
[5] Part II. Sect. 4.
[6] Book I. Part III. Sect. 10.
SECTION XII.
OF THE PRIDE AND HUMILITY OF ANIMALS.
Thus, in whatever light we consider this subject, we may still observe, that the causes of pride and humility correspond exactly to our hypothesis, and that nothing can excite either of these passions, unless it be both related to ourselves, and produces a pleasure or pain independent of the passion. We have not only proved, that a tendency to produce pleasure or pain is common to all the causes of pride or humility, but also that 'tis the only thing which is common, and consequently is the quality by which they operate. We have farther proved, that the most considerable causes of these passions are really nothing but the power of producing either agreeable or uneasy sensations; and therefore that all their effects, and amongst the rest pride and humility, are derived solely from that origin. Such simple and natural principles, founded on such solid proofs, cannot fail to be received by philosophers, unless opposed by some objections that have escaped me.
'Tis usual with anatomists to join their observations and experiments on human bodies to those on beasts; and, from the agreement of these experiments, to derive an additional argument for any particular hypothesis. 'Tis indeed certain, that where the structure of parts in brutes is the same as in men, and the operation of these parts also the same, the causes of that operation cannot be different; and that whatever we discover to be true of the one species, may be concluded, without hesitation, to be certain of the other. Thus, though the mixture of humours, and the composition of minute parts, may justly be presumed to be somewhat different in men from what it is in mere animals, and therefore any experiment we make upon the one concerning the effects of medicines, will not always apply to the other, yet, as the structure of the veins and muscles, the fabric and situation of the heart, of the lungs, the stomach, the liver, and other parts, are the same or nearly the same in all animals, the very same hypothesis, which in one species explains muscular motion, the progress of the chyle, the circulation of the blood, must be applicable to every one; and, according as it agrees or disagrees with the experiments we may make in any species of creatures, we may draw a proof of its truth or falsehood