Concerning benevolence, Smith stressed that sympathy expresses the genuine concern over the interests of others, in short "other-interest". This concern entails that the benefactor has to suspend his own interest. The negation of self-interest, however, does not mean that altruism stems from a principle, which is radically different from self-interest. For Smith, the motive to satisfy self-interest and other-interest stems from the same general tendency of humans to sympathize–in one case with the self and in the other with the beneficiary. That is, Smith did not view self-interest as radically different from other-interest : both are simply different instances of sympathy. We witness that man acts more often in sympathy with the self (i.e., out of self-interest) because man is obviously more familiar with the circumstance of his own self than with the circumstance of others. That is, for Smith, there is no fundamental distinction, but only a difference in degree, between one's own feelings as opposed to the feeling of others towards one's interest.
To be precise, however, Smith appears to note a difference between self-interest and the sympathy of others with one's interest. While self-interest seems to be an “original” sensation, the sympathy of others with one's interest does not take place immediately. Rather, it is a mediated or “reflected” sympathy with the agent who is originally experiencing the benefit or pain :
Every man, as the Stoics used to say, is first and principally recommended to his own care ; and every man is certainly, in every respect, fitter and abler to take care of himself than of any other person. Every man feels his own pleasures and his own pains more sensibly than those of other people. The former are original sensations ; the latter the reflected or sympathetic images of those sensation. The former may be said to be the substance, the latter the shadow (Smith (1976) p. 219).
That is, a spectator can assess a benefit or pain only through the reaction of the agent who is experiencing it. Nonetheless, this difference does not change the claim posited here that there is no fundamental distinction between self-interest and sympathy. When an agent sympathizes with someone else's feelings towards, e.g., an apple, it is a reflective sensation. Likewise, when the agent sympathizes with his own feelings towards the apple, it is also a reflective sensation : That is, both sensations involve sympathy and, hence, by definition, are reflective of original sensations. The only difference between the two cases arises from the degree of familiarity occasioned by the usual fact that the agent is more familiar with his own feelings than with the feelings of the other. (To note, however, this is not always true—as in the case when an agent is more attuned to the feelings of others than to his own.)