As we have no immediate experience of what other men feel, we can form no idea of the manner in which they are affected but by conceiving what we ourselves should feel in the like situation. Though our brother is upon the rack, as long as we ourselves are at our ease our senses will never inform us of what he suffers. They never did, and never can, carry us beyond our own person, and it is by the imagination only that we can form any conception of what are his sensations. Neither can that faculty help us to this any other way than by representing to us what would be our own, if we were in his case. It is the impressions of our own senses only, not those of his, which our imaginations copy. By the imagination we place ourselves in his situation, we conceive ourselves enduring all the same torments, we enter as it were into his body and become in some measure the same person with him, and thence form some idea of his sensations, and even feel something which, though weaker in degree, is not altogether unlike them. His agonies, when they are thus brought home to ourselves, when we have thus adopted and made them our own, begin at last to affect us, and we then tremble and shudder at the thought of what he feels. For, as to be in pain or distress of any kind excites the most excessive sorrow, so to conceive or to imagine that we are in it excites some degree of the same emotion, in proportion to the vivacity or dulness of the conception.

That this is the source of our fellow-feeling for the misery of others, that it is by changing places in fancy with the sufferer that we come either to conceive or to be affected by what he feels, may be demonstrated by many obvious observations, if it should not be thought sufficiently evident of itself. When we see a stroke aimed, and just ready to fall upon the leg or arm of another person, we naturally shrink and draw back our own leg or our own arm; and when it does fall, we feel it in some measure and are hurt by it as well as the sufferer. The mob, when they are gazing at a dancer on the slack rope, naturally writhe and twist and balance their own bodies as they see him do, and as they feel that they themselves must do if in his situation. Persons of delicate fibers and a weak constitution of body complain that in looking on the sores and ulcers which are exposed by beggars in the streets they are apt to feel an itching or uneasy sensation in the corresponding part of their own bodies. The horror which they conceive at the misery of those wretches affects that particular part in themselves more than any other because that horror arises from conceiving what they themselves would suffer if they really were the wretches whom they are looking upon, and if that particular part in themselves was actually affected in the same miserable manner. The very force of this conception is sufficient, in their feeble frames, to produce that itching or uneasy sensation complained of. Men of the most robust make observe that in looking upon sore eyes they often feel a very sensible soreness in their own, which proceeds from the same reason; that organ, being in the strongest man more delicate than any other part of the body, is the weakest.

Upon some occasions sympathy may seem to arise merely from the view of a certain emotion in another person. The passions upon some occasions may seem to be transfused from one man to another instantaneously and antecedent to any knowledge of what excited them in the person principally concerned. Grief and joy, for example, strongly expressed in the look and gestures of any person at once affect the spectator with some degree of a like painful or agreeable emotion. A smiling face is, to everybody that sees it, a cheerful object, as a sorrowful countenance, on the other hand, is a melancholy one.

This, however, does not hold universally, or with regard to every passion. There are some passions of which the expressions excite no sort of sympathy, but, before we are acquainted with what gave occasion to them, serve rather to disgust and provoke us against them. The furious behavior of an angry man is more likely to exasperate us against himself than against his enemies. As we are unacquainted with his provocation, we cannot bring his case home to ourselves, nor conceive anything like the passions which it excites. But we plainly see what is the situation of those with whom he is angry, and to what violence they may be exposed from so enraged an adversary. We readily, therefore, sympathize with their fear or resentment, and are immediately disposed to take part against the man from whom they appear to be in danger.

If the very appearances of grief and joy inspire us with some degree of the like emotions, it is because they suggest to us the general idea of some good or bad fortune that has befallen the person in whom we observe them: and in these passions this is sufficient to have some little influence upon us. The effects of grief and joy terminate in the person who feels these emotions, of which the expressions do not, like those of resentment, suggest to us the idea of any other person for whom we are concerned and whose interests are opposite to his. The general idea of good or bad fortune, therefore, creates some concern for the person who has met with it; but the general idea of provocation excites no sympathy with the anger of the man who has received it. Nature, it seems, teaches us to be more averse to enter into this passion, and, till informed of its cause, to be disposed rather to take part against it.

Even our sympathy with the grief or joy of another, before we are informed of the cause of either, is always extremely imperfect. General lamentations, which express nothing but the anguish of the sufferer, create rather a curiosity to inquire into his situation, along with some disposition to sympathize with him, than any actual sympathy that is very sensible. The first question which we ask is, What has befallen you? Till this be answered, though we are uneasy both from the vague idea of his misfortune and still more from torturing ourselves with conjectures about what it may be, yet our fellow-feeling is not very considerable.

Sympathy, therefore, does not arise so much from the view of the passion as from that of the situation which excites it. We sometimes feel for another a passion of which he himself seems to be altogether incapable, because, when we put ourselves in his case, that passion arises in our breast from the imagination, though it does not in his from the reality. We blush for the impudence and rudeness of another, though he himself appears to have no sense of the impropriety of his own behavior, because we cannot help feeling with what confusion we ourselves should be covered, had we behaved in so absurd a manner.

Of all the calamities to which the condition of mortality exposes mankind, the loss of reason appears, to those who have the least spark of humanity, by far the most dreadful; and they behold that last stage of human wretchedness with deeper commiseration than any other. But the poor wretch who is in it laughs and sings, perhaps, and is altogether insensible to his own misery. The anguish which humanity feels, therefore, at the sight of such an object cannot be the reflection of any sentiment of the sufferer. The compassion of the spectator must arise altogether from the consideration of what he himself would feel if he was reduced to the same unhappy situation, and, what perhaps is impossible, was at the same time able to regard it with his present reason and judgment.

What are the pangs of a mother when she hears the meanings of her infant, that, during the agony of disease, cannot express what it feels? In her idea of what it suffers, she joins to its real helplessness her own consciousness of that helplessness and her own terrors for the unknown consequences of its disorder; and, out of all these, forms for her own sorrow the most complete image of misery and distress. The infant, however, feels only the uneasiness of the present instant, which can never be great. With regard to the future it is perfectly secure in its thoughtlessness and want of anxiety, the great tormentors of the human breast, from which reason and philosophy will in vain attempt to defend it when it grows up to a man.