“We tend to think of our students’ minds as finite shoeboxes, and we then think we must take special care not to put anything in there if we do not want it to remain there for life. But the brain is more like a muscle. A student who learns one language, such as Latin, is not stuck with his shoebox three-quarters full, with no room for Spanish. Rather the student has a mind that has been stretched and exercised in such a way that subsequent learning is much easier, not much harder.
“Now of course this kind of mental discipline could be acquired by requiring of the students the intellectual equivalent of running back and forth. While a football coach might be able to get away with this, because everyone understands the point, we should not attempt it in the classroom—although mental wind sprints that had no point in themselves would still be better than simple laziness. The reason this approach would not work in the classroom is that the human mind is inescapably teleological; it wants to know why it is learning something. Latin has the advantage of providing the grist for the mill of the mind, while also providing great practical advantages. To return to our metaphor of football, the study of Latin is therefore simultaneously an exercise to prepare for the game and part of the game.”
From The Case for Classical Christian Education(Wheaton, IL: Crossway, 2003), 140-141.