Book IV is distinguished by a strong emphasis on the importance of tradition and reverence for the past. This is seen in the opening lines of Part A. There Mencius says, “Even if you had the keen eyes of Li Lou and the skill Kung-shu Tzu you could not draw squares or circles without a carpenter’s square or a pair of compasses” (76). He is again employing an argument from analogy. Just as one cannot draw a perfect circle without a compass, regardless of one’s natural skill in drawing, there are certain fields in which natural talent and enthusiasm are insufficient for success. Mencius applies this point to the art of governance. Rulers may have good intentions and even innate aptitude, but these will amount to little unless they “take advantage of the way of the Former Kings” (77). This means following the precepts created by the original sages and the practices of former exemplary rulers.

This argument is then used as a broader justification for a certain kind of social conservatism and traditionalism. Mencius stresses in section 1 that there is something superficial and disrespectful about criticizing former kings and ancestors.