5. Uncertainty has the same effect as opposition. The agitation of the thought, the quick turns which it makes from one view to another, the variety of passions, which succeed each other, according to the different views: All these produce an agitation in the mind; and this agitation transfuses itself into the predominant passion.
Security, on the contrary, diminishes the passions. The mind, when left to itself, immediately languishes; and in order to preserve its ardour, must be every moment supported by a new flow of passion. For the same reason, despair, tho' contrary to security, has a like influence.
6. Nothing more powerfully excites any affection than to conceal some part of its object, by throwing it into a kind of shade, which, at the same time, that it shows enough to prepossess us in favour of the object, leaves still some work for the imagination. Besides, that obscurity is always attended with a kind of uncertainty; the effort, which the fancy makes tocompleat
