From an essay I’m writing: “As Giambattista Vico maliciously points out, a proto-cogito is stated to comic effect in a Roman play, Amphitryon, in which a less-than-clever character mutters to himself: ‘Yet when I think, I am equally certain that I am the same’ (Sed quom cogito, equidem certo idem sum). It is certainly tempting to conclude that modern philosophy begins with an ancient joke …”
The Latin quoted here differs slightly from that quoted in G. Vico, On the Most Ancient Wisdom of the Italians, Drawn out of the Origins of the Latin Language, trans. J. Taylor (New Haven – London: Yale University Press, 2010), 32–33.
D. L. Dusenbury 