But, again, as facility converts pain into pleasure, so it often converts pleasure into pain when it is too great, and renders the actions of the mind so faint and languid, that they are no longer able to interest and support it. And indeed scarce any other objects become disagreeable through custom, but such as are naturally attended with some emotion or affection, which is destroyed by the too frequent repetition. One can consider the clouds, and heavens, and trees, and stones, however frequently repeated, without ever feeling any aversion. But when the fair sex, or music, or good cheer, or any thing that naturally ought to be agreeable, becomes indifferent, it easily produces the opposite affection. But custom not only gives a facility to perform any action, but likewise an inclination and tendency towards it, where it is not entirely disagreeable, and can never be the object of inclination. And this is the reason why custom increases all _active_ habits, but diminishes _passive_, according to the observation of a late eminent philosopher. The facility takes off from the force of the passive habits by rendering the motion of the spirits faint and languid. But as in the active, the spirits are sufficiently supported of themselves, the tendency of the mind gives them new force, and bends them more strongly to the action. SECTION VI. OF THE INFLUENCE OF THE IMAGINATION ON THE PASSIONS. 'Tis remarkable, that the imagination and affections have a close union together, and that nothing, which affects the former, can be entirely indifferent to the latter. Wherever our ideas of good or evil acquire a new vivacity, the passions become more violent, and keep pace with the imagination in all its variations. Whether this proceeds from the principle above-mentioned, _that any attendant emotion is easily converted into the Predominant_, I shall not determine. 'Tis sufficient for my present purpose, that we have many instances to confirm this influence of the imagination upon the passions. Any pleasure with which we are acquainted, affects us more than any other which we own to be superior, but of whose nature we are wholly ignorant. Of the one we can form a particular and determinate idea: the other we conceive under the general notion of pleasure; and 'tis certain, that the more general and universal any of our ideas are, the less influence they have upon the imagination. A general idea, though it be nothing but a particular one considered in a certain view, is commonly more obscure; and that because no particular idea, by which we represent a general one, is ever fixed or determinate, but may easily be changed for other particular ones, which will serve equally in the representation.