This essay, starting from a Prologue of a comedy composed in 1605 in a dialogic shape by Flaminio Scala, the director of the Compagnia dei Confidenti, lingers over two Galilei’s theatrical scenarios, the first one dating back to the Pisa-period, before 1592, and the second one to the years of the paduan stay (1592-1610), showing a Galilei committed with mathematical speculations but also jovially opened to the literary clubs heirs of Ruzzante and promoters of a literature conceived as life style, as ultimate inclination towards reality and nature. ‘Inventions of fantasy’ and ‘geometrical severity’ meet theirselves into Galilei’s “scientifical-poetical imagination”, approaching the experimentalism of the new theatrical form of the ‘commedia all’improvviso’ in a ‘divertissement’ shaped attitude, but also inspiring, in those joyful years of the ‘Patavina libertas’, a tasty dialogue in pavan language (written by any chance by the benedictine and scholar Girolamo Spinelli); a dialogue that, between rustic expressions and tributes to Ruzzante, openings to daily idioms, to the living and common things language, shows the subversive and burlesque opposition of the lettered-scientist standing for a new philosophy of nature against the linguistic and mental dogmatism of aristotelicians.