Being fully convinc’d of the influence of this relation, I try the effects of the other; and by changing virtue for vice, convert the pleasant impression, which arises from the former, into the disagreeable one, which proceeds from the latter. The effect still answers expectation. Vice, when plac’d on another, excites, by means of its double relations, the passion of hatred, instead of love, which for the same reason arises from virtue. To continue the experiment, I change anew the relation of ideas, and suppose the vice to belong to myself. What follows? What is usual. A subsequent change of the passion from hatred to humility. This humility I convert into pride by a new change of the impression; and find after all that I have compleated the round, and have by these changes brought back the passion to that very situation, in which I first found it.
Hume’s argument, written in the geometric style (it’s a circle), is seducing: it moves from one passion to the other, by transitivity, in order to show the completeness and the unicity of Hume’s [system](https://journal.loupbrun.ca/en/n/092/ on the passions.
He thus gives the impression of having gone through (or around) the possible passions and that his system works without a fault—in part maybe because it is so simple, whereas complexity is naturally error-prone.