Final answer:
Vanity and boastfulness are vices in Aristotle's framework that deviate from the virtue of truthfulness, with vanity seeking undue validation and boastfulness exaggerating true qualities for gain.
Step-by-step explanation:
In Aristotle's Nicomachean Ethics, both vanity and boastfulness are indeed vices, yet they can be distinguished by their particular excesses in relation to the mean of truthfulness. Vanity involves an excess where a person claims unsupported merits or seeks external validation beyond what is truly deserved. In contrast, boastfulness may appear similar, but it centers on the exaggeration of existent qualities, often for personal gain or specific ends.
Aristotle describes both as deviating from the virtue of truthfulness, which necessitates an honest presentation of oneself. The boastful person embellishes the truth about their achievements, perhaps to gain admiration or advantage, while the vain individual seeks undue acknowledgment and validation. Both vices exhibit a misguided desire for external esteem, but they engage in different methods of self-promotion.