But if you listen to the complaints of a forsaken lover, you observe that he insists largely on the pleasures which he enjoyed, or hoped to enjoy, and on the perfection of the object of his desires; it is the _loss_ which is always uppermost in his mind.
The violent effects produced by love, which has sometimes been even wrought up to madness, is no objection to the rule which we seek to establish.

When men have suffered their imaginations to be long affected with any idea, it so wholly engrosses them as to shut out by degrees almost every other, and to break down every partition of the mind which would confine it.

Any idea is sufficient for the purpose, as is evident from the infinite variety of causes, which give rise to madness: but this at most can only prove, that the passion of love is capable of producing very extraordinary effects, not that its extraordinary emotions have any connection with positive pain.
SECTION IX.
THE FINAL CAUSE OF THE DIFFERENCE BETWEEN THE PASSIONS BELONGING TO SELF-PRESERVATION AND THOSE WHICH REGARD THE SOCIETY OF THE SEXES.
The final cause of the difference in character between the passions which regard self-preservation, and those which are directed to the multiplication of the species, will illustrate the foregoing remarks yet further; and it is, I imagine, worthy of observation even upon its own account.

As the performance of our duties of every kind depends upon life, and the performing them with vigor and efficacy depends upon health, we are very strongly affected with whatever threatens the destruction of either: but as we were not made to acquiesce in life and health, the simple enjoyment of them is not attended with any real pleasure, lest, satisfied with that, we should give ourselves over to indolence and inaction.

On the other hand, the generation of mankind is a great purpose, and it is requisite that men should be animated to the pursuit of it by some great incentive.