可 (Kě) — Can Be

Say "kuh," dipping and then rising. Thirty-six appearances across twenty chapters, two of them in the book's first six characters.

Locked: 可 → "can be" (before a verb, the subject is what the verb is done to) / "can" (as 可以, the subject does the verb) / "cannot" (不可, for what the situation does not allow). (Not "must not" or "should not" for a plain 不可; see Cannot, not must not below. No check can hold that ruling; see What no rule can enforce.)

可 says what a situation allows. It is not a person's strength or skill; that is 能 (néng), its partner, treated below. 可 is the gap in the world through which a thing can happen, and 不可 is a world with no such gap. The book uses it most often in the negative, and almost always about the Tao or about the world, saying what cannot be done to them.

The graph: a mouth, and a breath getting out

Our vendored 說文解字 (Shuōwén Jiězì): 𦘫也。从口丂，丂亦聲 — "to consent. From 口 (kǒu — mouth) and 丂 (kǎo), and 丂 also gives the sound."

• 口 (kǒu) is a mouth. 說文: 人所以言食也, "what a person speaks and eats with."
• 丂 (kǎo) is drawn as a breath pushing up against a line. 說文 describes it as breath that wants to come out and is held back from above. In 可 it does two jobs: it is the sound, and it is the breath leaving the mouth.

The oldest sense is permission, not possibility. 𦘫 is the old form of 肯 (kěn — to be willing, to agree). So for Xu Shen 可 is the mouth saying yes: all right, it may be done. Some modern scholars propose an even older sense, to sing, since 可 written twice is 哥, and 歌 (gē — song) is built on it. That is a tentative proposal. What is certain is that the word began as someone allowing something, and possible is that permission read off the world instead of a person. 可 is in the Shang oracle bones, already in this shape.

That sense never left. 朝聞道，夕死可矣 (論語 4.8) is "hear the way in the morning, and in the evening you may die." And modern Chinese still answers yes, fine with 可以.

Two constructions, two voices

This is the grammar the English must keep, and the first line depends on it.

可 + verb: the subject receives the action. 道可道 is "the Tao that can be made into a way." 名可名 is "the name that can be named." The Tao is not doing the dào-ing. It is what would be dào-ed. The same construction gives 可欲 (3), "what can be desired," which English has as one word: the desirable.

可以 + verb: the subject acts. 可以 is 可 with 以 (yǐ — by means of), "has the means to." 可以長久 (44, 59) — "you can last long." 可以有國 (59) — "you can have the state." 美言可以市尊 (62) — "fine words can buy honor."

With an intransitive verb, 可 is simply can. 大道汎兮，其可左右 (34) — "the great Tao overflows. It can go left or right." 左右 (zuǒ yòu) is used as a verb with nothing to act on, so there is no one to receive the action and the subject just can.

One 可以 in our base is a copying error. 知止可以不殆 (32) stands alone against every other witness, which read 所以 (suǒ yǐ — that by which): knowing when to stop is how you come to no danger. We follow 所以 (notes/manuscript.md, Ch 32), so the line carries no can.

The line can be checked by swapping the forms: 道可以道 would mean the Tao can make a way. The book does not say that.

Cannot, not must not

不可 has two readings, and English has to choose between them every time:

• cannot: the situation does not allow it, so trying fails.
• must not: you are forbidden to.

The book means the first. The pattern is clearest at chapter 29, the line that matters most:

天下神器，不可為也，不可執也。為者敗之，執者失之。 "The world is a sacred vessel. It cannot be handled. It cannot be grasped. Those who handle it ruin it. Those who grasp it lose it."

The next sentence gives the reason, and the reason is a result, not a rule: handle it and it breaks. 王弼 (Wáng Bì) reads it exactly that way: 萬物以自然為性，故可因而不可為也，可通而不可執也。物有常性而造為之，故必敗也 — "the countless things take being so of themselves as their nature. So they can be followed and cannot be handled, can be passed through and cannot be grasped. Things have their own nature, and to manufacture them is to ruin them, surely." 必 (bì — surely, without fail) is a prediction. 河上公 (Héshàng Gōng) agrees: 以有為治之則敗其質性, "govern it by handling, and you ruin its nature." Must not would turn a description of how the world works into a commandment. That is a verdict the line does not carry (process/principles/no-verdict-the-chinese-lacks.md).

The other lines run the same way. 不可致詰 (14), it cannot be questioned through to the end. 善閉無關楗而不可開 (27), masterful security uses no locks, yet cannot be breached. 不可得而親 (56), you cannot draw them near. 王弼's gloss on 56 is a logic, not a law: 可得而親，則可得而疏也, "if they could be drawn near, they could be held off."

不可不 is the one place must belongs. 人之所畏，不可不畏 (20) is cannot not fear, and English says that as must: "What people fear must be feared." This must is still necessity rather than a command. 王弼 reads it in the first person: 人之所畏，吾亦畏焉, "what people fear, I fear too."

能, the partner: a bear

能 (néng) is the other English can: ability, what an agent is able to do. It appears thirty-three times across seventeen chapters, often as 孰能 (who can…?) and 莫能 (no one can).

Our 說文: 熊屬。足似鹿。从肉㠯聲。能獸堅中，故稱賢能；而彊壯，稱能傑也 — "a kind of bear, with feet like a deer's. From 肉 (ròu — flesh), with 㠯 (yǐ) for sound. The 能 beast is solid at its core, and so the able are called 賢能; and it is strong, and so the outstanding are called 能傑." The graph is a bear: two paws, and a head with an open mouth. The word for the animal later took 火 (fire, here four dots for the feet) and became 熊 (xióng). Xu Shen's account of how a bear came to mean able is a commentator's story, but the picture is right for the word: 能 is strength in a body.

The voice keeps them apart in English. 可 is can be, the situation's allowance. 能 is can or is able to, someone's power. 莫之能守 (9) — "no one can guard them" — is a failure of ability. 不可長保 in the same chapter — "it will not keep for long" — is the world not allowing it. Where both stand together, the book is saying something about each. At 70: 吾言甚易知，甚易行…天下莫能知，莫能行 — "my words are very easy to know, very easy to follow. In all the world, no one can know them. No one can follow them." The words can be known. People cannot know them. The fault is in the agents, not the words.

What we set aside

• must not / should not for a plain 不可 — puts a commandment where the book describes a consequence (above). Chapter 36 is the case where it came closest to fitting, and cannot holds there too (below).
• may — the oldest sense, and fine in 論語, but in modern English may means perhaps as often as is permitted. "The Tao that may be made into a way" would read as a guess.
• is possible to / is able to be — accurate and wooden. 可 is a small word and wants a small English word.
• -able suffixes (nameable, graspable) — compact, but they turn a statement about the world into a property of the thing. "It is ungraspable" says what the Tao is like. "It cannot be grasped" says what happens when you try. The book means the second. The desirable (3) is the one exception, because 可欲 is a fixed noun and English has the noun.

Chapter 36, the hardest line

魚不可脫於淵，國之利器不可以示人。 "A fish cannot leave deep water. / A state's tools of advantage cannot be shown."

The two clauses are one parallel, and the English keeps it. Both read cannot (Shalom's call, 2026-10-14).

Why cannot for both:

• 王弼 reads both halves as one consequence: 魚脫於淵則必見失矣。利國器而立刑以示人，亦必失也 — "a fish that leaves the deep is surely lost. To set up punishments as the state's tools and show them to people, that too is surely lost." 亦 (yì — also) ties the two clauses together, and 必 makes both predictions.
• The fish line is plainly not advice. A fish is not forbidden to leave the water. It dies. The second line borrows the first's logic.
• The chapter keeps its musts for the four 必固 lines ("you must first stretch it out…"), where 必 (bì) prints them.

What it costs: 河上公 hears advice: 治國權者不可以示執事之臣也, "the authority that governs the state must not be shown to the ministers who run affairs." 韓非 (Hán Fēi) reads the whole chapter as counsel to a ruler: rewards and punishments, the state's 利器, 在君則制臣，在臣則勝君, "held by the lord they control the ministers; held by the ministers they overcome the lord." And 可以 rather than 可 marks the second clause slightly differently from the first. On their reading the line is a warning to rulers, and must never would be honest to it. That reading is set aside, not refuted.

What no rule can enforce

Must not and should not are ruled out for a plain 不可, and they cannot go on forbidden:. Must is 不可不's English at 20, and chapter 36 prints must four times for 必 (bì), in the same chapter as two 不可. The checker keys on chapter presence, so forbidding must would flag correct lines. The reader holds this one: 不可 is cannot; must belongs to 必 and to 不可不.

Left open

Chapter 35's never is softer than the Chinese. 用之不可既 is "use it, and it cannot be used up." "It never runs out" reports a record, where 不可 says the world doesn't allow it. The never is declared as a flexion because the line sounds right, but it is a small loss.

English can serves both characters. The voice usually keeps them apart (can be against can), but where 可以 makes the subject act, 可以 and 能 land on the same English. 可以有國 (59), "you can have the state," and 能守之 (32), "able to hold to this," are different claims, an opening and a capacity. English barely shows it.