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, it is 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 so ever 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.