Full Idea
If someone were to take the celestial globe of Posidonius and show it to the people of Britain, would a single one of those barbarians fail to see that it was the product of a conscious intelligence?
Gist of Idea
If the barbarians of Britain saw a complex machine, they would be baffled, but would know it was designed
Source
M. Tullius Cicero (On the Nature of the Gods ('De natura deorum') [c.44 BCE], II.88)
Book Reference
Cicero: 'The Nature of the Gods', ed/tr. McGregor,Horace [Penguin 1972], p.159