this should happen in natural philosophy.  The essence and composition of external bodies are so obscure, that we must necessarily, in our reasonings, or rather conjectures concerning them, involve ourselves in contradictions and absurdities.  But as the perceptions of the mind are perfectly known, and I have used all imaginable caution in forming conclusions concerning them, I have always hoped to keep clear of those contradictions, which have attended every other system.  Accordingly the difficulty, which I have at present in my eye, is nowise contrary to my system; but only departs a little from that simplicity, which has been hitherto its principal force and beauty.

The passions of love and hatred are always followed by, or rather conjoined with benevolence and anger.  It is this conjunction, which chiefly distinguishes these affections from pride and humility.  For pride and humility are pure emotions in the soul, unattended with any desire, and not immediately exciting us to action.  But love and hatred are not compleated within themselves, nor rest in that emotion, which they produce, but carry the mind to something farther.  Love is always followed by a desire of the happiness of the person beloved, and an aversion to his misery:  As hatred produces a desire of the misery and an aversion to the happiness of the person hated.  So remarkable a difference betwixt these two sets of passions of pride and humility, love and hatred, which in so many other particulars correspond to each other, merits our attention.

The conjunction of this desire and aversion with love and hatred may be accounted for by two different hypotheses.  The first is, that love and hatred have not only a cause, which excites them, viz, pleasure and pain; and an object, to which they are directed, viz, a person or thinking being; but likewise an end, which they endeavour to attain, viz, the happiness or misery of the person beloved or hated; all which views, mixing together, make only one passion.  According to this system, love is nothing but the desire of happiness to another person, and hatred that of misery.  The desire and aversion constitute the very nature of love and hatred.  They are not only inseparable but the same.

But this is evidently contrary to experience.  For though it is certain we never love any person without desiring his happiness, nor hate any without wishing his misery, yet these desires arise only upon the ideas of the happiness or misery of our friend or enemy being presented by the imagination, and are not absolutely essential to love and hatred.  They are the most obvious and natural sentiments of these affections, but not the only ones.  The passions may express themselves in a hundred ways, and may subsist a considerable time, without our reflecting on the happiness or misery of their objects; which clearly proves, that these desires are not the same with love and hatred, nor make any essential part of them.