Thus it appears, that the principle, which opposes our passion, cannot be the same with reason, and is only called so in an improper sense. We speak not strictly and philosophically when we talk of the combat of passion and of reason. Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them. As this opinion may appear somewhat extraordinary, it may not be improper to confirm it by some other considerations.

A passion is an original existence, or, if you will, modification of existence, and contains not any representative quality, which renders it a copy of any other existence or modification. When I am angry, I am actually possest with the passion, and in that emotion have no more a reference to any other object, than when I am thirsty, or sick, or more than five foot high. It is impossible, therefore, that this passion can be opposed by, or be contradictory to truth and reason; since this contradiction consists in the disagreement of ideas, considered as copies, with those objects, which they represent.

What may at first occur on this head, is, that as nothing can be contrary to truth or reason, except what has a reference to it, and as the judgments of our understanding only have this reference, it must follow, that passions can be contrary to reason only so far as they are accompanyed with some judgment or opinion. According to this principle, which is so obvious and natural, it is only in two senses, that any affection can be called unreasonable. First, When a passion, such as hope or fear, grief or joy, despair or security, is founded on the supposition or the existence of objects, which really do not exist. Secondly, When in exerting any passion in action, we chuse means insufficient for the designed end, and deceive ourselves in our judgment of causes and effects. Where a passion is neither founded on false suppositions, nor chuses means insufficient for the end, the understanding can neither justify nor condemn it.

It is not contrary to reason to prefer the destruction of the whole world to the scratching of my finger. It is not contrary to reason for me to chuse my total ruin, to prevent the least uneasiness of an Indian or person wholly unknown to me. It is as little contrary to reason to prefer even my own acknowledgeed lesser good to my greater, and have a more ardent affection for the former than the latter. A trivial good may, from certain circumstances, produce a desire superior to what arises from the greatest and most valuable enjoyment; nor is there any thing more extraordinary in this, than in mechanics to see one pound weight raise up a hundred by the advantage of its situation. In short, a passion must be accompanyed with some false judgment in order to its being unreasonable; and even then it is not the passion, properly speaking, which is unreasonable, but the judgment.

The consequences are evident. Since a passion can never, in any sense, be called unreasonable, but when founded on a false supposition or when it chuses means insufficient for the designed end, it is impossible, that reason and passion can ever oppose each other, or dispute for the government of the will and actions. The moment we perceive the falshood of any supposition, or the insufficiency of any means our passions yield to our reason without any opposition. I may desire any fruit as of an excellent relish; but whenever you convince me of my mistake, my longing ceases. I may will the performance of certain actions as means of obtaining any desired good; but as my willing of these actions is only secondary, and founded on the supposition, that they are causes of the proposed effect; as soon as I discover the falshood of that supposition, they must become indifferent to me.

It is natural for one, that does not examine objects with a strict philosophic eye, to imagine, that those actions of the mind are entirely the same, which produce not a different sensation, and are not immediately distinguishable to the feeling and perception. Reason, for instance, exerts itself without producing any sensible emotion; and except in the more sublime disquisitions of philosophy, or in the frivolous subtilties of the school, scarce ever conveys any pleasure or uneasiness. Hence it proceeds, that every action of the mind, which operates with the same calmness and tranquillity, is confounded with reason by all those, who judge of things from the first view and appearance. Now it is certain, there are certain calm desires and tendencies, which, though they be real passions, produce little emotion in the mind, and are more known by their effects than by the immediate feeling or sensation. These desires are of two kinds; either certain instincts originally implanted in our natures, such as benevolence and resentment, the love of life, and kindness to children; or the general appetite to good, and aversion to evil, considered merely as such.

When any of these passions are calm, and cause no disorder in the soul, they are very readily taken for the determinations of reason, and are supposed to proceed from the same faculty, with that, which judges of truth and falshood. Their nature and principles have been supposed the same, because their sensations are not evidently different.

Beside these calm passions, which often determine the will, there are certain violent emotions of the same kind, which have likewise a great influence on that faculty. When I receive any injury from another, I often feel a violent passion of resentment, which makes me desire his evil and punishment, independent of all considerations of pleasure and advantage to myself. When I am immediately threatened with any grievous ill, my fears, apprehensions, and aversions rise to a great height, and produce a sensible emotion.

The common error of metaphysicians has lain in ascribing the direction of the will entirely to one of these principles, and supposing the other to have no influence. Men often act knowingly against their interest: For which reason the view of the greatest possible good does not always influence them. Men often counter-act a violent passion in prosecution of their interests and designs: It is not therefore the present uneasiness alone, which determines them. In general we may observe, that both these principles operate on the will; and where they are contrary, that either of them prevails, according to the general character or present disposition of the person. What we call strength of mind, implies the prevalence of the calm passions above the violent; though we may easily observe, there is no man so constantly possessed of this virtue, as never on any occasion to yield to the sollicitations of passion and desire.

From these variations of temper proceeds the great difficulty of deciding concerning the actions and resolutions of men, where there is any contrariety of motives and passions.

There is not in philosophy a subject of more nice speculation than this of the different causes and effects of the calm and violent passions. It is evident passions influence not the will in proportion to their violence, or the disorder they occasion in the temper; but on the contrary, that when a passion has once become a settled principle of action, and is the predominant inclination of the soul, it commonly produces no longer any sensible agitation. As repeated custom and its own force have made every thing yield to it, it directs the actions and conduct without that opposition and emotion, which so naturally attend every momentary gust of passion. We must, therefore, distinguish betwixt a calm and a weak passion; betwixt a violent and a strong one. But notwithstanding this, it is certain, that when we would govern a man, and push him to any action, it will commonly be better policy to work upon the violent than the calm passions, and rather take him by his inclination, than what is vulgarly called his reason.

We ought to place the object in such particular situations as are proper to encrease the violence of the passion. For we may observe, that all depends upon the situation of the object, and that a variation in this particular will be able to change the calm and the violent passions into each other. Both these kinds of passions pursue good, and avoid evil; and both of them are encreased or diminished by the encrease or diminution of the good or evil. But herein lies the difference betwixt them: The same good, when near, will cause a violent passion, which, when remote, produces only a calm one. As this subject belongs very properly to the present question concerning the will, we shall here examine it to the bottom, and shall consider some of those circumstances and situations of objects, which render a passion either calm or violent.

It is a remarkable property of human nature, that any emotion, which attends a passion, is easily converted into it, though in their natures they be originally different from, and even contrary to each other. It is true; in order to make a perfect union among passions, there is always required a double relation of impressions and ideas; nor is one relation sufficient for that purpose. But though this be confirmed by undoubted experience, we must understand it with its proper limitations, and must regard the double relation, as requisite only to make one passion produce another. When two passions are already produced by their separate causes, and are both present in the mind, they readily mingle and unite, though they have but one relation, and sometimes without any. The predominant passion swallows up the inferior, and converts it into itself.

The spirits, when once excited, easily receive a change in their direction; and it is natural to imagine this change will come from the prevailing affection. The connexion is in many respects closer betwixt any two passions, than betwixt any passion and indifference.

When a person is once heartily in love, the little faults and caprices of his mistress, the jealousies and quarrels, to which that commerce is so subject; however unpleasant and related to anger and hatred; are yet found to give additional force to the prevailing passion. It is a common artifice of politicians, when they would affect any person very much by a matter of fact, of which they intend to inform him, first to excite his curiosity; delay as long as possible the satisfying it; and by that means raise his anxiety and impatience to the utmost, before they give him a full insight into the business. They know that his curiosity will precipitate him into the passion they design to raise, and assist the object in its influence on the mind. A soldier advancing to the battle, is naturally inspired with courage and confidence, when he thinks on his friends and fellow-soldiers; and is struck with fear and terror, when he reflects on the enemy. Whatever new emotion, therefore, proceeds from the former naturally encreases the courage; as the same emotion, proceeding from the latter, augments the fear; by the relation of ideas, and the conversion of the inferior emotion into the predominant.

Hence it is that in martial discipline, the uniformity and lustre of our habit, the regularity of our figures and motions, with all the pomp and majesty of war, encourage ourselves and allies; while the same objects in the enemy strike terror into us, though agreeable and beautiful in themselves.

Since passions, however independent, are naturally transfused into each other, if they are both present at the same time; it follows, that when good or evil is placed in such a situation, as to cause any particular emotion, beside its direct passion of desire or aversion, that latter passion must acquire new force and violence.