The great translator and scholar, D. C. Lau, passed away on Monday. I never met Professor Lau but I am one of those touched by his erudition and eloquence. As I look around my office, his work is nearby. His translations of The Analects and Mencius are at hand. I have learned from his Introduction to Mencius. Here is an excerpt, which provides nuance to the general point that Mencius asserted an innately good human nature:
...First of all, let us dispose of certain misunderstandings. It has been said that Mencius put forth his theory solely with sages in mind, as the sage is the only type of man who possesses unadulterated goodness. This it to restrict the application of Mencius' theory to sages, but as Mencius makes it quite clear that his theory is meant to apply universally to all men, there much be something wrong with this interpretation.
Mencius nowhere contradicted Kao Tzu's statement that "appetite for food and sex is nature". He would probably admit that desires and appetites form the greater part of human nature. What he emphatically denied was that human nature consisted solely of desires and appetites. According to him, "Slight is the difference between man and the brutes. The common man loses this distinguishing feature, while the gentleman retains it" (IV.B 19). To say that the difference between man and the brutes is slight is to imply that they are, for the most part, the same, and if the nature of animals consists solely of desires and appetites, then these must also make up the greater part of human nature. There is, however, a difference, and this, though slight, sets man apart from animals. Whether a man is a gentleman or not depends on whether he succeeds in retaining, and, we may say, developing this difference. But what is this distinguishing feature that the gentleman retains? The answer is, it is his heart (hsin). In IV.B 28, Mencius says, "A gentleman differs from other men in that he retains his heart." This "retaining of the heart" is again mentioned in VII.A 1. It is necessary to emphasize the retention of the heart because it is something very easy to lose. Since the heart is something we possess originally, it is also referred to as the "original heart". Mencius describes a man who loses his sense of shame and comes to do things for unworthy motives which he would not, in the first instance, have done even to escape death as a man who has lost his "original heart" (VI.A 100. Mencius also calls it the "true heart". It is not the case that a man never possessed the benevolent and righteous heart, but that he has "let go of his true heart" (VI.A 8). We are said to "let go" of the heart because we possessed it in the first place. The purpose of learning is "to go after this strayed heart" (VI.A 11). 13-14
So, let's remember Professor Lau by remembering what Mencius teaches us: don't lose heart...