You can force water to jump up, he said, by striking it, and by mechanical appliances you can make it flow to the top of a hill; but what you do in such cases is entirely contrary to the nature of water, and is merely the result of violence, such violence, in fact, as is brought into play when man's nature is bent towards evil.
"That which men get at birth," said Kao, "is their nature," implying that all natures were the same, just as the whiteness of a white feather is the same as the whiteness of white snow; whereupon Mencius showed that on this principle the nature of a dog would be the same as that of a an ox, or the nature of an ox the same as that of a man.

Finally, Mencius declared that for whatever evil men may commit, their natures can in nowise be blamed.

In prosperous times, he argued, men are mostly good, whereas in times of scarcity the opposite is the case; these two conditions, however, are not to be charged against the natures with which God sent them into the world, but against the circumstances in which the individuals in question have been situated.
The question, however, of man's original nature was not set permanently at rest by the arguments of Mencius.

A philosopher, named Hsun Tzu (_Sheundza_), who flourished not very much later than Mencius, came forward with the theory that so far from being good according to Confucius, or even neutral according to Kao, the nature of man at birth is positively evil.

He supports this view by the following arguments.
From his earliest years, man is actuated by a love of gain for his own personal enjoyment.