In Edward Slingerland’s translation of the Analects, he mentions Ma Rong’s commentary on 18.6, the passage in which, in answer to Zilu’s request (from Confucius) for directions to a particular ford, a daoist-like figure says to Zilu that Confucius “should know where the ford is.” (是知津矣！). About this passage, Ma Rong claims that it is because Confucius is known to travel widely around the countryside to advise rulers and ministers in various states that the daoist-like figure takes a swipe at him with this snide remark.
It occurs to me that there is probably more to it than that. Although I agree that Ma Rong’s analysis is the correct surface reading of the passage, I think this is meant to illustrate something different, a deeper perceived disagreement (by Confucians) between Confucian-inclined and Daoist-inclined people. Given the Confucian claim that the right way to live is by following and instilling in society the Li (“Ritual”) of the Zhou kings, coming to know the right thing to do is (in some sense) coming to know the Zhou li, and thus there is a sense in Confucius that knowledge is a grasping and following of things already revealed, that is, available “collective knowledge”.
For the daoist (especially Zhuangzi–and as Slingerland notes, the use of descriptive names for the daoist-like characters in Analects 18.5-18.7 seems to suggest these passages were written after the Zhuangzi, perhaps in response), we cannot gain full knowledge of dao (“the way”) by looking to the past, because the dao is not limited by what we might call the “collective knowledge of humanity.” Dao is not something humans once attained and then lost. It is contingent on each person to reconcile themselves with the state of nature, or natural propensities, in order to follow dao. Since natural propensities are always changing, the daoist sage is always on his toes, so to speak.
In contrast to this, the Confucian conception of ethical knowledge seems static (or, in a more positive light, stable), and so the response “he should know where the ford is” might be taken as a statement of a Zhuangzi-type daoist’s problem with Confucians; namely, that Confucians are to them “know-it-alls”, presumptuous scholars who think that the Zhou li in some way exemplifies human knowledge. So the quote “he should know where the ford is” might be seen as a glove to the face. Another way the quote may have been written, to make the same point: “If all one needs to know is the ancient ways, why does Confucius need to ask me anything? What knowledge can he gain from me? He should already know all there is to know, right?”
If this interpretation of 18.6 is right, then it begins to look like these “Confucius responds to daoists” passages in Book 18 are less biased toward Confucius than they seem. Instead, perhaps they try to lay out the debate between the camps, even if in the end their representation of the daoist is still a bit straw-mannish. Of course, a Confucian couldn’t be expected to present daoist concerns as fairly or forcefully as someone like Zhuangzi