No More Learning

For the pure
conception of duty, unmixed with any foreign addition of empirical
attractions, and, in a word, the conception of the moral law,
exercises on the human heart, by way of reason alone (which first
becomes aware with this that it can of itself be practical), an
influence so much more           than all other springs [Footnote: I
have a letter from the late excellent Sulzer, in which he asks me
what can be the reason that moral instruction, although containing
much that is convincing for the reason, yet accomplishes so little?