There have been many discussions of the creative role of metaphors and similes in the scientific imagination, particularly of the 17th century. Metaphors become sense-loaded when they cross the uncertain boundaries between the sciences and religion, philosophy and literature: such was the metaphor of light, so fashionably used in Newton’s lifetime to eulogize his discoveries. I do not refer only to the literary exploitation of the experiments on colours. Ever since the first edition the text of the
Principia
was preceded by Halley’s verses, containing some typical metaphors. The secrets of the heavens were finally laid open: ‘
Intima panduntur victa penetralia caeli
... Matters that vexed the mind of ancient seers.../Now are seen in reason’s light; the clouds of ignorance/ Dispelled at last by science’ (1)*. The Halley ode, stuffed with fragments borrowed from Lucretius, is one of the sources of a copious and repetitive stream of variations on the theme. As Moses revealed the Tables of the Law or, reading between the lines, as Epicurus exorcized the fear of celestial phenomena, so Newton introduced mankind to the banquet of the gods by revealing the main mystery of nature. Roger Cotes, in his authorized preface of 1713, echoed the same note: ‘
Dici vix potest quanta lux accedat
... The gates are now set open, and by the passage he has revealed we may freely enter into the knowledge of the hidden secrets and wonders of natural things ’ (2).