For this I pretend not to give any reason; but consider such a peculiar direction of the thought as an original quality.
The SECOND quality, which I discover in these passions, and which I likewise consider an an original quality, is their sensations, or the peculiar emotions they excite in the soul, and which constitute their very being and essence.

Thus pride is a pleasant sensation, and humility a painful; and upon the removal of the pleasure and pain, there is in reality no pride nor humility.

Of this our very feeling convinces us; and beyond our feeling, it is here in vain to reason or dispute.
If I compare, therefore, these two established properties of the passions, viz, their object, which is self, and their sensation, which is either pleasant or painful, to the two supposed properties of the causes, viz, their relation to self, and their tendency to produce a pain or pleasure, independent of the passion; I immediately find, that taking these suppositions to be just, the true system breaks in upon me with an irresistible evidence.

That cause, which excites the passion, is related to the object, which nature has attributed to the passion; the sensation, which the cause separately produces, is related to the sensation of the passion: From this double relation of ideas and impressions, the passion is derived.

The one idea is easily converted into its correlative; and the one impression into that, which resembles and corresponds to it: With how much greater facility must this transition be made, where these movements mutually assist each other, and the mind receives a double impulse from the relations both of its impressions and ideas?
That we may comprehend this the better, we must suppose, that nature has given to the organs of the human mind, a certain disposition fitted to produce a peculiar impression or emotion, which we call pride: To this emotion she has assigned a certain idea, viz, that of self, which it never fails to produce.