This article does not have any sources. (July 2014)
Mencius said, "The woods on Ox Mountain were once beautiful! On account of its being on the edge of a large country, it had been attacked with axes and hatchets, and then how could it remain beautiful? The refreshing breezes of day and night, and the moisture provided by rain and fog, did not fail to give rise to sprouts of vegetation. But cows and sheep have been repeatedly pastured there, and for that reason it has remained desolate. People observe its denuded state and assume that it never had any good resources. But how could this state be the true nature of this mountain?" — Mencius, 6A:8
Mencius argued that "bad" human natures were produced just as the bad condition of Ox Mountain had been produced, so the answer to "bad" humans was to protect and nurture them from birth. He also thought that punishment does not do much good. It does not cure the root of the problem.