Both the causes and effects of these violent and calm passions are pretty variable, and depend, in a great measure, on the peculiar temper and disposition of every individual.

Generally speaking, the violent passions have a more powerful influence on the will; though it is often found, that the calm ones, when corroborated by reflection, and seconded by resolution, are able to controul them in their most furious movements.

What makes this whole affair more uncertain, is, that a calm passion may easily be changed into a violent one, either by a change of temper, or of the circumstances and situation of the object, as by the borrowing of force from any attendant passion, by custom, or by exciting the imagination.

Upon the whole, this struggle of passion and of reason, as it is called, diversifies human life, and makes men so different not only from each other, but also from themselves in different times.
Philosophy can only account for a few of the greater and more sensible events of this war; but must leave all the smaller and more delicate revolutions, as dependent on principles too fine and minute for her comprehension.
SECT.

IX OF THE DIRECT PASSIONS It is easy to observe, that the passions, both direct and indirect, are founded on pain and pleasure, and that in order to produce an affection of any kind, it is only requisite to present some good or evil.