On p. 303 of Readings, Xunzi considers the Confucian slogan (cf. Mencius 4B32, 6B2) “Anyone on the streets could become a Yu”, i.e., everyone can become a sage, a superlatively virtuous agent. At one level, the slogan does not pose a problem for Xunzi—he has already insisted that everyone has the same nature, therefore, if anyone could become virtuous, all could. But spelling this out properly is tricky since Xunzi needs his account not to imply that virtue is part of nature and that’s why all can become virtuous agents. He begins by way of something definitional:

(1) A (superlatively) virtuous agent is what he is because he exemplifies the various dimensions of virtue (“benevolence, righteousness, lawfulness, and correctness”).

We will also need to keep in mind other assumptions that are unstated in the text here, but needed for his argument to work:

(2) (Superlatively) virtuous agents exist.

(3) Everyone have the same nature.

Since actuality implies possibility, Xunzi draws two conclusions from the above:

(4) The various dimensions of virtue have patterns that are knowable and practicable. (From (1), (2))

(5) Even the man on the street as the material for knowing, and the equipment for practicing, the various dimensions of virtue.* (From (1)-(4)).

(*The underlying Chinese is actually somewhat complicated, but this is the standard reading that is given in all the usual translations and commentaries.) Xunzi does not say it explicitly, but he clearly connects “the material for knowing, and the equipment for practicing, the various dimensions of virtue” with our nature. Such a move would also fit nicely with the analogy presented earlier, where our nature appears as if clay or wood that can be shaped or carved to make tiles and utensils. Such a connection would explain how he got from (1)-(3) to (4).

The two conclusions (4) and (5) are meant to be his explication of what the slogan meant (or what he wants it to mean anyway). The sequel follows up on the argument so far by considering what would happen if we deny (4) and (5):

(4’) The various dimensions of virtue do not have patterns that are knowable and practicable. (Supposition)

(5’) The man on the street as does not originally have the material for knowing, and the equipment for practicing, the various dimensions of virtue. (Supposition)

(6) (An erstwhile sage) Yu did not know or practice the various dimensions of virtue. (From (4’), contradicting (2), thus showing that (4’) is false assuming that (2) is granted.)

(7) The man on the street would not be able to know or practice the various dimensions of virtue (From (5’), contradicting the slogan, thus showing that (5’) is false assuming the slogan.)

Xunzi then concludes the section by saying more about what it takes for the man of the street to actually become a (superlatively) virtuous agent—they can do so if they were to “use their material for understanding these things and the equipment for practicing them”, and “base themselves upon the knowable patterns and practicable aspects of [virtue]”. This happens “if they were to concentrate their heart and make single-minded their intentions, if they were to ponder, query, and thoroughly investigate”, and “if they add to this days upon days and connect to this a long period of time, if they accumulate goodness without stopping”. Since all that is, in a suitable sense, doable for the man on the street, it follows that they “can” become sages.

The more critical among you would (and should) be asking: Xunzi, really? Even the random man on the street “can” do all that? Is that really plausible? After all, isn’t it true—and this is something that Confucians surely agree with—that the virtuous are few and the non-virtuous many. What Xunzi needs to explain is why, even though all could—as the slogan says—not all do; some clearly are even vicious. And relatedly, perhaps even though all could, not all really could—in some other sense of “could”. That’s the burden of the next section.