Catholic religion, which he thought was manifestly false. He also thought that the Catholic Church represented one dangerous extreme—with Calvinism at the other end of the spectrum—that threatened the stability of the Anglican settlement to which he had devoted himself.

In common with most of his fellow Protestants, Swift will doubtless have referred to Catholics as Papists. And the term crops up on a couple of occasions in "A Modest Proposal," where the fictitious scientist recommends his plan as a way of reducing the number of so-called Papists in Ireland. Such a vast reduction in the numbers of those deemed as potential fifth columnists would certainly have made Swift sleep a lot more soundly in his bed at night.

Many readers of "A Modest Proposal" assume that Swift's primary target throughout the essay is the English for their callous mis-treatment of Ireland and the Irish, and the English are among Swift's targets in this masterful satire.  As he makes clear at the end of the essay and as he made clear in his other writings on the "Irish question," however, he is directing this proposal to the Irish themselves, specifically, those in Ireland who make policy.

Throughout most of the essay, Swift maintains his persona of modest proposer, particularly when he is actually discussing the various elements of turning children into an edible commodity, but he does step away from the persona to address issues not directly related to his proposal.  He notes, for example, that certain people "of a desponding Spirit" are worried about the "vast Number of poor People" (the old, sick, and disabled) and wonder what can be done about them.  His response is less proposer and more Swift--not to worry:

. . . because it is very well known, that they are every Day dying, and rotting, by Cold and Famine, and Filth, and Vermin, as fast as can be reasonably expected.

In this short passage, he makes an observation that only someone intimately familiar with Ireland can make.  More important, perhaps, is the fact that the essay's audience understands that they are not only guilty because of policies that have helped destroy Ireland's economy and its people but also for their failure to enact policies to protect the most vulnerable people in this society.

At the end of the essay, Swift steps away from the proposer persona completely and explicitly indicts the Irish:

. . . I calculate my  Remedy for this one individual Kingdom of Ireland, and for no other that ever was, is, or I think ever can be upon Earth. Therefore, let no man talk to me of other Expedients: Of taxing our Absentees at five Shillings a Pound. . . Of utterly rejecting the Materials and Instruments that promote foreign Luxury. . . .

Swift goes on to create a catalogue of solutions that actually could benefit the Irish, but he concludes that he will not hear of these solutions unless there is "a Glimpse of Hope" that they will be put into practice.  Had he stayed within the essayist's persona of proposer, Swift would not have been able to discuss these solutions primarily because they would have weakened the proposal by acknowledging that real solutions already exist.

By stepping outside the persona of the modest proposer in these digressions, Swift is able to make observations and use arguments that he has used in prior direct discussions of Irish problems, and he reminds his audience that reasonable solutions already exist, if only the Irish would adopt them.

Swift uses several methods of conveying a rational, humane tone in the opening paragraphs of "A Modest Proposal" before revealing what the actual proposal is.

First, the writer presents himself as a man of compassion, citing the unfortunate state of affairs in Ireland and the poverty that exists there. He claims that the mothers,

[...] instead of being able to work for their honest livelihood, are forced to employ all their time in strolling to beg sustenance for their helpless infants who, as they grow up, either turn thieves for want of work, or leave their dear native country to fight for the Pretender in Spain, or sell themselves to the Barbadoes.

Second, he presents himself as a man of science, criticizing the judgement of others who have studied the same situation and claiming that his own research has yielded new information:

As to my own part, having turned my thoughts for many years upon this important subject, and maturely weighed the several schemes of other projectors, I have always found them grossly mistaken in their computation.

He then goes into a series of computations of his own regarding the demographics of Ireland, citing statistics about the total population, the number of women of child-bearing age, and the number of children who need to be cared for, in the guise of one whose wish is nothing more than to alleviate suffering. All of this gives a pseudo-technical veneer to the ideas being expressed, so that the reader finds himself or herself reflexively agreeing with the writer and judging him compassionate and wise, until his actual plan is suddenly revealed:

I have been assured by a very knowing American of my acquaintance in London, that a young healthy child well nursed is at a year old a most delicious, nourishing, and wholesome food, whether stewed, roasted, baked, or boiled; and I make no doubt that it will equally serve in a fricassee or a ragout.

Today we can hopefully find additional amusement in Swift's alluding to "a very knowing" American as the source of his information about the benefits of cannibalism. But this caps off the whole style of the introductory paragraphs in which Swift's persona sounds so kind, rational, genial and authoritative, that the reader is ready to agree with anything he proposes.

Swift's persona, whose views are the opposite of Swift himself, falsely believes himself to be a reasonable person. He believes it is perfectly rational, and even kind, to suggest fattening and selling the babies of the poor for the rich to eat. The word "modest" as a way to describe this proposal shows that this utterly clueless narrator thinks his idea is reasonable. The word "modest" means unassuming. It means ordinary, as a modest home could be described as very ordinary; however, this proposal is anything but ordinary. 

The narrator also focuses closely on the nitty-gritty of such "rational" parts of his proposals as a careful calculation of the profitability of raising a baby for a year to be sold as food and showing how much "return" a poor mother would get on the investment. He talks about the benefits of the "commerce" in babies to such things as Ireland's balance of trade. By emphasizing these economic benefits, he completely loses sight of the moral depravity of what he is suggesting.

Through this narrator, Swift is arguing that viewing humans only in economic terms is dehumanizing. Humans are more than economic units and deserve genuine compassion that isn't based on profit and loss.

Swift's narrator starts out in a very reasonable voice. He expresses his "melancholy" impression of the hapless, begging mothers, followed by their many children, who roam the streets of Dublin in rags. He seems to think of and to treat them sympathetically, describing them as those "who demand our charity," and he assumes that any readers would agree that theirs is a pitiable state. Another quite reasonable moment comes when the speaker describes the way in which his proposal, if implemented, would prevent women from killing their infants, either because they cannot afford them or because of the shame of bearing a child out of wedlock. He says,

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 expense than the shame, which would move tears and pity in the most savage and inhuman breast.

Not only does it sound, then, as though he is interested in the moral good—preventing mothers from committing infanticide—but he also continues to insist on the sympathetic plight into which these women are thrust.

In the satirical essay "A Modest Proposal," author Jonathan Swift certainly does mix a reasonable voice with a more absurd tone to convey his satire.

One example of his use of reason can especially be seen where he makes a list of six rational arguments to defend his satirical point of view. The first rational argument he lists is that consuming children would decrease the "number of Papists," meaning supporters of the Catholic Church, since Papists are the "principle breeders of the nation, as well as our most dangerous enemies." One reason why he says most of the nation is bred by Papists is because Ireland is predominantly a Catholic nation. A second reason why he says most of the nation is bred by Papists is because, due to religious views, Catholics have many children. He also says that Papists are the nation's enemies because Ireland was at the time being oppressed by England's Royalist supporters, who were Protestant and wealthy, leaving the Catholics to be the poorest and most oppressed and hated citizens of Ireland. Hence, Catholics were being treated as enemies of the nation even if they weren't truly enemies.

One of his most reasonably-sounding arguments is that, if children were sold for consumption, the "poorer tenants will have something valuable of their own," which they can use to help them out of their poverty and to "pay their landlord's rent."

Hence, all throughout the essay, Swift employs a voice of reason by making the argument sound rational. He then couples his rational argument with irony to create and emphasize his satire.

In Swift's "A Modest Proposal," the foundation of the work is what you refer to as the "reasonable voice" of the narrator.  This sets up everything else in the work, including the irony, which contibutes so greatly to the essay's success.  Nothing the narrator says would work if the narrator did not appear to be reasonable.  His argument is based on reason.

The narrator begins by establishing how much he cares about the Irish people.  This is vital.  His argument must seem to be for the Irish people, not against them.  For instance, he writes:

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.

This is a reasonable, as well as an honorable goal. 

Once he is established as reasonable and as being on the side of the Irish people, his modest proposal (which is anything but modest), once it is revealed, creates the irony which dominates the essay.  The narrator remains rational and unemotional for the remainder of the essay, using facts and statistics as one might use to solve a math or science problem.   

I am not really clear on what you are asking. Are you asking about how Swift uses the voice of the "authorial persona" to narrate this essay?

This essay is about the strongest example of satire that you can find. Under the guise of a person with authority (authorial persona), Swift "proposes" his solution for overpopulation in Ireland. As the essay unfolds, he gives information about overpopulation and the reader believes he/she is reading a social essay that is going to offer a worthwhile solution to overpopulation, infant mortality, abortion, etc., until you come to this line:

I shall now therefore humbly propose my own thoughts, which I hope will not be liable to the least objection.

I have been assured by a very knowing American of my acquaintance in London, that a young healthy child well nursed is at a year old a most delicious, nourishing, and wholesome food, whether stewed, roasted, baked, or boiled; and I make no doubt that it will equally serve in a fricassee or a ragout.

We then learn that the "modest proposal" is that the children be used for food! And this is not a modest proposal, it is an outrageous proposal, thus the satire, because Swift is using something outrageous to bring our attention to the problem.

Read the analysis right here on eNotes.

If this is not what you are asking about, please re-post your question.

In this essay, Swift is emphasizing his satire by adopting such a reasonable tone of voice as he writes.  This makes his essay seem serious.  The seriousness adds to the satire.

Some examples of his reasonable voice might include:

• He uses statistics.  He talks about how many people live in Ireland.  He quite seriously calculates how many children might be made available and how much money they would cost their parents to raise, etc.
• He cites authorities -- like quoting sources in a modern news article.  He claims to have interviewed merchants to find out how feasible his plan is.

In the satirical essay "A Modest Proposal: For Preventing the Children of Poor People in Ireland from Being a Burden on Their Parents or Country and for Making Them Beneficial to the Publick," the narrator or speaker is dismayed by the many mothers with young children begging on the streets. To alleviate this condition, he suggests raising young Irish children to be food for aristocrats. In this way, he proposes, instead of children being a burden on Irish mothers, they will make a profit by selling them for meat. The number of beggars on the streets will be diminished, and a savory new source of food will be found for aristocratic tables.

The author of this scathing satire is Jonathan Swift, a writer whose best-known work is another satire, the novel Gulliver's Travels. He was born in 1667 in Dublin, Ireland. His father had recently died, and he grew up in poverty. He was also afflicted with a disease that affected his hearing and caused him nausea and dizziness. After graduating from college, Swift served as an Anglican priest. His writings, which made fun of the church as well as British politics and society, became extremely popular. Swift was a person of good moral character who used his writings to comment on the social, political, and religious problems of his era.

To write "A Modest Proposal," Swift adopts the voice of a speaker who is nothing like himself. The narrator of this essay is a deranged psychotic who sees nothing wrong with Great Britain becoming a cannibalistic nation that murders and feeds on its own children. He even gives the mathematical details of how much money fattening the children would cost and suggests different ways in which the children could be cooked.

Swift uses these extremes to highlight the indifference that aristocratic people felt towards the plight of the poor. The speaker in this essay is an exaggerated example of a rich person who feels so superior to those less financially fortunate that he does not comprehend how abhorrent and disgusting his ideas are.

We see, then, that Jonathan Swift and the fictitious person he creates as the speaker in his essay are people with vastly different personalities and attitudes toward others.

The speaker is a scientist presenting a learned discussion paper, the kind that would be put before the Royal Society, Great Britain's national academy of sciences. Swift was scathing of many of the ideas put forward at the Royal Society, which he saw as useless, dangerous, or, in some cases, both. And it's just such ideas that he's satirizing in "A Modest Proposal".

What makes the "Proposal" particularly effective is the empirical language it uses, exactly the kind of language you'd see in a scientific paper. Though the ideas advanced in the paper are truly revolting and morally reprehensible, the scientific language in which they are presented gives them an academic credibility and respectability which they simply don't deserve.

As the paper's central thesis—that children should be bred for meat—is so disgusting to all right-thinking people, it needs to be cloaked in the bloodless language of science to make it more palatable. If the paper had been written in the style of a polemic, then it would've been rejected by just about everyone. But because it's couched in the language of a learned scientific paper then more people are likely to stop and think that maybe what's being proposed isn't such a bad idea after all and should therefore be given due consideration.