The purpose of Swift's "Modest Proposal" is, first, to expose people's attitudes (particularly those in power) toward the poverty in Ireland and, second, for the author to give his own opinion on the situation.
Swift does this by combining realism with irony, absurdity, and parody. Swift writes the essay in the authoritative tone of an educated person using a structured, seemingly reasonable argument.
I shall now therefore humbly, propose my own thought, which I hope will not be liable to the least objection.
He also backs it up with the use of statistics.
The number of souls in this kingdom being reckoned one million and a half. Of these I calculate there may be about two thousand couples whose wives are breeders, from which number I subtract thirty thousand couples...
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