In the eighteenth century we witness a relationship of mutual influence and contamination between philosophy and literature that ends up transforming them both. On the one hand, the new philosophical interests influence the development of the genre of the tale or novel, in its stylistic and content aspects. On the other hand, the novelistic genre allows eighteenth-century philosophy to express, in a factual way, theoretical aspects that it would hardly convey differently. The philosophy of the eighteenth century, and in particular that of the Enlightenment, was in fact profoundly multi-faceted and dialogical. It was interested in investigating those aspects of reality that escape a merely rational explanation, but also in reflecting on the meaning of feelings and passions. For these reasons, it is reductive to study the relationship between philosophy and novel through the category of “philosophical novel”: one can instead speak, more radically, of the development of a “literary philosophy”. The philosophical question of the relationship between corporeality (or sensoriality) and reason will be taken as an emblematic example of this dynamic. This question is crucial in two eighteenth-century fantastic tales: Voltaire’s Micromegas and J. Swift’s Gulliver’s Travels.