Swift does this mainly through his complete mastery of style. He was a superb satirist and his talent is nowhere more evident than in this work. Irony permeates the entire piece, from the title to the closing sentence. Swift has his speaker assume the most moderate and reasonable tone even when making the most appalling suggestion - that the poverty-stricken Irish people should sell their children as food. He sets out the argument in logical steps, pointing out that this would relieve the Irish people of the burden of having to raise children in poor conditions and earn them money. In this way, he says, the children can serve a useful purpose instead of having to grow up in misery. He points out the social and economic advantages of such a proposition in the clinical, detached manner of sociologists, economists and statisticians the world over.
What Swift effectively does in this essay is to employ shock-tactics to jolt the reader into an awareness of the terrible living conditions in Ireland at that time, due in no small part to oppression by the English. On a purely logical level, the argument is perfectly sound, but the moral objection is overwhelming. Swift of course understood this; the whole piece, despite its apparently mild tone, is consummately and savagely ironic. It certainly has left a memorable impression on its readers over the centuries. Indeed, A Modest Proposal is probably the most famous essay in all of English literature.