"The greatest secret in education

consists in exciting and directing the will: that system is the best which elicits the greatest amount of voluntary exertion from the learner. By calling forth all the resources of the student, and making him conscious of his progress, a rational method leads him to incessant spontaneous efforts; it does not dispense with labor, it directs and seconds it; it does not impose learning on the memory, it indicates the means of acquiring it, of making discoveries, and thus renders study accessible to those who are unable to procure masters.

-pg. 25, The Study of Languages Brought Back to Its True Principles or The Art of Thinking in a Foreign Language (1869) by C. Marcel.