Final answer:
The primary consideration of the speaker's argument in 'A Modest Proposal' is economics, as it satirically addresses the economic struggles of the Irish by suggesting they sell their children as food.
Step-by-step explanation:
In A Modest Proposal, the primary consideration of the speaker's argument is economics. Jonathan Swift satirically suggests that the impoverished Irish might ease their economic troubles by selling their children as food to rich gentlemen and ladies. This outlandish thesis is a stark commentary on the dire economic conditions and the indifference of the wealthy towards the poor during that period.