What is the major logical fallacy in "A Modest Proposal"?

Two major fallacies are in evidence throughout the masterful and enduringly relevant text of "A Modest Proposal." The first and most immediately obvious is the appeal to authority. The author-in-character consciously adopts a tone of paternalistic knowingness, setting himself up as an authority with no real grounds to do so by quoting unsubstantiated statistics:

The number of Souls in this Kingdom being usually reckoned one Million and a half, Of these I calculate there may be about two hundred thousand Couple whose Wives are breeders, from which number I Subtract thirty Thousand Couples, who are able to maintain their own Children... I again Subtract fifty Thousand for those Women who miscarry, or whose Children dye by accident, or disease within the Year...

The reader is given no assurance as to the source or accuracy of these statistics, since their purpose is to give an effect of authority, rather than to encourage rational analysis. The fallacious appeal to authority is furthered and augmented by quoting an unnamed "very worthy Person, a true Lover of his Country, and whose Virtues I highly esteem," adding the non-sequitur to the parade of fallacies Swift intends to expose (what does the author's opinion matter?). A further authority quoted, "the famous Sallmanaazor, a Native of the Island Formosa," is actually fictitious, further highlighting the absurdity of continually deferring to absent authorities when rational justification is lacking. 

A second fallacy that pervades "A Modest Proposal" is the appeal to emotion, which is pursued in several forms. The vivid depiction of poverty in the early paragraphs is intended to provoke an emotional response that will make any proposal desirable, if only it will diminish the spectacle of such suffering. Such appeal is most pronounced in the following paragraph: 

There is likewise another great Advantage in my Scheme, that it will prevent those voluntary Abortions, and that horrid practice of Women murdering their Bastard Children, alas! too frequent among us, Sacrificing the poor innocent Babes, I doubt, more to avoid the Expence, than the Shame, which would move Tears and Pity in the most Savage and inhuman breast.

Here the author-in-character relies on the pity, shame and disgust provoked in his readers, rather than the strictures of reason and justice, to render his proposal more palatable. The shame that appears here as elsewhere is linked to patriotism, with references to "the present deplorable state of the Kingdom," "a true Lover of his Country," and to bigotry in the form of religious hatred, revealed in the pointed reference to "lessening the number of Papists among us."