The Metaphysics of Morals by Immanuel Kant Chapter 2 Page 14

despises the latter, and can by degrees become their master; whereas a mixed ethics, compounded partly of motives drawn from feelings and inclinations, and partly also of conceptions of reason, must make the mind waver between motives which cannot be brought under any principle, which lead to good only by mere accident and very often also to evil.

* 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? My answer was postponed in order that I might make it complete. But it is simply this: that the teachers themselves have not got their own notions clear, and when they endeavour to make up for this by raking up motives of moral goodness from every quarter, trying to make