(cfr. Rosa Marinoni Mingazzini, Luciana Salmoiraghi, Mirror of the Times, Napoli, Morano, 1989, pp.314-315)

Swift shared Erasmus’ and Voltaire’s view of mankind, but, unlike them, he had what has been called "a stroke of satirical genius", i.e. he realized that it was enough to alter the scale or size of men to make them either ridiculous or contemptible.

He maintained, in fact, that man is not a reasonable animal, but simply an animal endowed with reason, which he is not always able to use in the right way. This contrast between "rationality" and "animality" is at the basis of the whole work. In fact:

in Book 1 (A voyage to Lilliput)

– rationality is represented by the Lilliputians, with their perfect organization and their deep knowledge of all mathematical sciences, in contrast with Gulliver, described only as a big "body" dominated by physiological needs.

(But the Lilliputians have perverted their rationality into an instrument of cruelty and domination.)

in Book 2- (A Voyage to Brobdingnag)

– the situation is reversed, the giants embodying animality, with their large, disgusting bodies, and Gulliver rationality thanks to his ability and skilfulness..

(But the giants’ King, though physically repulsive, is generous and endowed with a great sense of morality, as is shown by his comment on the words of Gulliver who, to show him the superiority of his own age and culture, proudly describes to him the institutions of England, which are in fact undermined by corruption and immorality.)

in Book 3 (A Voyage to Laputa)

– the main themes are science, philosophy and their purposes as evidence of man’s rationality.

(But these purposes are ridiculed and often compared with others which are perfectly absurd, to show that men, too proud of their rationality, have forgotten their basic common sense. Besides showing that Swift had not understood Bacon’s experimental philosophy and the directions taken by modern science, this also reveals how 18th-century science had totally lost that harmony between intellect and senses that characterized, for instance, Renaissance science.)

in Book 4 – (A voyage to the Country of the Houyhnhnms)

- reason is represented in its extreme, pure form by the horses, in contrast with the "bodies" of the abominable Yahoos.

(But the horses, though they are models of honesty and morality, ignore emotions, and so they lack the peculiar features that could make them "human".)

What lessons does Swift want to teach in his masterpiece? Through his "contrast-within-contrast" technique, he dissects mankind, denouncing its follies and absurdities. But his satire is never purely destructive. However coarse, violent and sometimes revolting it may be, it betrays Swift’s wish for a greater use of common sense and a greater balance between "rationality" and "animality".