In typical revolutionary tone, Rousseau (1712-1778) expounds on the limits of reason and rhetoric in a call for a new age based on the powerful use of signs.
"One of the errors of our age is to use reason in too unadorned a form, as if men were all mind. In neglecting the language of signs that speak to the imagination, the most energetic of languages has been lost. The impression of the word is always weak, and one speaks to the heart far better through the eyes than through the ears (compare this!). . . . always to reason is the mania of small minds. Strong souls have quite another language.”
The Romans understood this language of signs, he goes on, citing the examples of Thrasybulus and Tarquin “cutting off the tops of poppies” and Antony bringing in the body of dead Caesar. Rousseau compares his own age unfavorably with that of the ancient Romans, who “did not neglect the language of signs.” It is this “abolishment of signs,” he laments, that has led to a society that respects nothing but brute force.
Also see Kant’s response to Rousseau: the idea of “kultur,” developed in his three critiques (see “Origins of Civilization”)