Models of taste as regards the arts of speech must be composed in a dead and learned language. The first in order that they may not suffer that change which inevitably comes over living languages, in which noble expressions become flat, common ones antiquated, and newly crated ones have only a short circulation. The second because learned languages have a grammar which is subject to no wanton change of fashion, but the rules of which are preserved unchanged.
[Kant, Critique of Judgement. Bernard, tr. Hafner Press (New York: 1951), p. 68.]
Later he mentions, in passing that "we, and rightly, recommend the works of the ancients as models and call their authors classical, thus forming among writes a kind of noble class who give laws to the people by their example" (p. 124). Kant makes a distinction between imitating and following a model, and is very much against the first, which is just copying; what we should do instead is follow in their footsteps by drawing on the same sources as the model, using the model only in order to learn how to do this. But whereas this leads him to disparage models and examples very severely in moral philosophy, he argues that we actually need examples in the philosophy of taste in order to indicate what has received approval, not just in our time, but throughout the ages. Judgments of taste, like all important judgments imply a sort of universality, but the universality in taste is not, as in morals, an objective universality arising from intrinsic necessity, but is instead a subjective universality. This makes it a much less certain thing, and trickier to establish; we need to posit classical models that please through centuries as a sort of minimum supporting this subjective universality and thus preventing us from losing the successes of civilization and thereby sliding back into barbarism. These classical models, however, have to be stable themselves, being examples of well-established and unchanging rules, in order to do this.
I can't help but smile at the idea of Kant talking with some kinds of modern thinkers about the classics.
KANT: It is extremely important for society that people learn Classical Latin and/or Greek.
MODERN: Why Latin and Ancient Greek, when there are so many other languages that can be learned?
KANT (patiently): Obviously because Classical Latin and Greek are dead languages.