I was thinking about this today as I was driving around (the time between meetings). I think that classical Christian education and the culture that it supports are committed to crossing Kant's line and maintaining (virulently) that Christianity is true! Not true in our hearts or true in our opinion, but true! Factually, objectively, true. And this truth makes life good and beautiful.
Kant's line was made between the subjective and the objective in 1781 (I believe this is the date of The Critique of Pure Reason. He, trying to protect Christianity, relegated it to the subjective. The faith was true, but only true to US and true IN OUR HEARTS.This pious activity has led to our current anemic faith which makes Christ the Lord of our hearts, but not our lives and not the world outside of our hearts (i.e., the Supreme Court, or the schools of our country, or your backyard).
So definitionally classical Christian education is the joyful affirmation that the facts of the faith are true and that trusting Christ leads to beauty and goodness.