往圣还需不需要我来继绝学 / Do the sages still need me?

一句用了很多年的话

“为往圣继绝学”是张载四句里的一句。我从少年时起就把它当成一件值得向往的事，也一直照着做。但这些年，每次备完课，看着一份自己只出了一半力的课件，我都会想起这句话，然后想：现在还成立吗？

不是“还需要人教书吗”。是更冷的一个：还需要“我”吗。

三个字，三件事

“继绝学”三个字，其实装着三件不同的事。

“学”，是学问本身——定理、证明、哪一步推到哪一步。这件事 AI 已经做完了。任何一个本科生今晚想弄懂一个东西，他可以问到一个比我有耐心、比我不累、凌晨三点还在的回答。我讲了十年的课，它能在一分钟里讲一遍，而且讲得比我清楚。

“继”，是传递。这件事也基本被接管了。从前一门学问能传下去，靠的是有人肯花二十年把它抄一遍、讲一遍、再讲一遍。现在不需要抄，也不需要背。需要的只是有人愿意打开它。

于是只剩下中间那个字：绝。

“绝”不是失传，是没人要了

我一直以为“绝学”是失传——书烧了，人没了，手艺断了。后来发现不是。书都在，而且比历史上任何时候都更容易拿到。断掉的不是文本，是意愿。

一门学问会“绝”，通常不是因为它错了，也不是因为它难，而是因为它不再被需要：不考了，不赚钱了，不解决什么问题了。人是理性的，没人会去学一个既不给分也不给工作的东西。

而意愿这件事，模型补不上。不是能力问题——它写劝学的文章比我写得好——是它没有“想学”这回事。它不缺什么，所以它不渴望什么。渴望只能从人身上长出来，也只能传到人身上。

这么一想，老师的活就变了。从前我是“知道答案的那个人”，现在我更像一个看火的人：不负责生火，负责别让它灭。

那为什么非得是我

写到这里我很想停住，因为下一句不太好听。

如果老师真正要做的事只是“让下一个人还想读”，那这件事不需要是我。任何一个讲得清楚、又真心在乎的人都能做，也许做得比我好。我并没有什么不可替代的地方。

这个结论让人不舒服。我们这行的人，多少都靠着“这件事非我不可”的幻觉活着。

但反过来想，它也许是好事。如果非我不可，那它就是我的负担；如果谁做都行、但总得有人做，那它就只是一件需要有人去做的事——而我恰好在这里，愿意做。这比“非我不可”轻，也比“非我不可”稳。

所以我把题目反过来问

写到这儿我发现，题目问反了。

“往圣还需不需要我来继绝学”——这句话预设了我是被挑的那一方，在等着被录用。但真正要紧的是另一半：我还需不需要往圣。

如果我不需要——如果我教书只是为了那份工资、那个职称、走廊里那声“老师好”——那么“继绝学”就只是我的修辞，跟我没关系。如果我还需要——如果我自己也还在被这些东西养着，还会因为某个下午一个证明推得漂亮而高兴——那么“继”就不是义务，是我自己的活法。

我大概是后者。教了这些年书，我从学生那里学到的，不比他们从我这里学到的少；我为讲清楚一个概念熬的那些夜，最后都变成了我自己对这门学科的理解。所谓“继绝学”，说到底不是我在替古人做事，是古人在替我做一件事：给我一个可以一直学下去的理由。

具体做什么

具体的事，其实没什么新鲜的：把备课材料放出去、作业里不禁止 AI、课上少讲多答、把课堂往小班答疑那边挪。都是些笨办法。

它们有一个共同点：把“传递”让出去，把“愿意”留下来。

至于“继绝学”这三个字，我现在不太敢用了。它太大，也太悲壮。我更愿意说：我在看一炉火，添一把柴，等下一双手伸过来。

A sentence I have used for years

为往圣继绝学 — to continue the discontinued learning of the sages — is one line of a four-line vow that Zhang Zai wrote a thousand years ago, and that Chinese schoolchildren still learn by heart. I have wanted a part in it since I was a boy. But in recent years, every time I finish preparing a class and look at a set of slides I only half made, the line comes back, and I have to ask: is it still true?

Not “are teachers still needed”. Something colder: am I?

Three characters, three jobs

The phrase does three things at once.

The learning itself — the theorems, the proofs, which step follows which. That job is finished. Any undergraduate who wants to understand something tonight can ask something more patient than I am, that does not get tired, and that is awake at three in the morning. I have taught this material for ten years; it can explain it in a minute, and explain it better.

The passing on. That job has largely been taken over too. Scholarship used to survive because someone was willing to copy it out, teach it, teach it again, for twenty years. Nobody needs to copy it now. What is needed is someone willing to open it.

Which leaves the middle character: 绝, the discontinued, the cut-off.

“Discontinued” does not mean lost

I always assumed 绝学 meant lost — the books burned, the teachers gone, the craft broken. It does not. The books are all here, more available than at any point in history. What is broken is not the text. It is the wanting.

A subject dies out not because it is wrong or difficult, but because it stops being needed: no exam, no salary, no problem it solves. People are rational. Nobody studies something that gives neither marks nor a job.

And wanting is the one thing a model cannot supply. Not for lack of ability — it writes a better case for studying than I ever could — but because it has nothing to want. It lacks nothing, so it craves nothing. Craving grows in people and travels between people.

Which changes what a teacher is for. I used to be the one who knows the answer. Now I am closer to someone tending a fire: not responsible for the flame, responsible for it not going out.

Then why me

I would like to stop here, because the next sentence is not flattering.

If all a teacher really has to do is make the next person still want to read, then it does not have to be me. Anyone who explains clearly and genuinely cares can do it, probably better. There is nothing irreplaceable about me.

That is uncomfortable. Most of us in this trade live off the illusion that it could not be anyone else.

But it may be good news. If it could only be me, it is a burden. If anyone could do it and somebody must, then it is simply a thing that needs doing — and I happen to be here, willing. That is lighter than being indispensable, and steadier.

So I turn the question round

Writing this, I notice the title asks it the wrong way.

“Does the canon still need me to carry it” assumes I am the one being interviewed, waiting to hear whether I am wanted. The half that matters is the other one: do I still need it?

If I do not — if I teach for the salary, the title, the greeting in the corridor — then 继绝学 is just a flourish, and none of it is about me. If I do — if I am still fed by these things, still pleased on some afternoon because a proof came out clean — then continuing it is not a duty. It is how I live.

I am probably the second kind. In these years of teaching I have learned from students about as much as they learned from me, and every night spent making one idea clear ended up as my own understanding of the subject. 继绝学, in the end, is not me doing something for the ancients. It is the ancients doing something for me: giving me a reason to keep learning.

What that looks like

Concretely, nothing new: I put my prep material online, I do not ban AI in assignments, I spend less of the hour talking and more of it answering, I push the class towards small-group work. Clumsy measures, all of them.

They have one thing in common: hand over the transmission, keep the wanting.

As for the phrase itself — I have become shy of it. It is too large, and too tragic. I would rather say: I am watching a fire, putting on another log, waiting for the next pair of hands.