The Verb That Never Quite Commits

Marcos got there before Sophia had even set down her tablet.

Marcos. Modal verbs. You said it after nouns. You said it after pronouns. You said it again after relative clauses, not ten minutes ago, in front of witnesses. Four promises.

Sophia. (setting the tablet down flat, without ceremony) Five, if we count generously. I've been counting too. Today it happens, and you may hold me to that the moment I try to wander off again. Philo — say your sentence from three days ago. The whole thing.

Philo. "You must return the old Roman heavy scroll by evening." Though I've fixed the adjectives since.

Sophia. Keep the adjectives as they are now and forget them entirely — today "must" is the only word in that sentence I care about. Marcos, why did Philo reach for "must," and not "should," or "could," or "will"? They all point roughly the same direction.

Marcos. They sound close enough to me. I couldn't tell you what's actually different.

Sophia. By the end of the lesson you will. That's rather the whole shape of what we're doing today — these words all lean on a main verb the same way, sit in the same slot in the sentence, and yet each one is quietly making a completely different claim about how sure, how required, or how permitted something is. We call the whole family modal verbs.

Sophia. Start with "must" itself, since Philo has already handed it to us. Two students, two sentences. Philo — you said "must" because your own sense of what's owed told you so, nobody standing over you insisting on it. Now, Marcos — give me a sentence about something you're required to do, not because anyone in this room said so, but because a rule outside all of us says so.

Marcos. I have to register at the prefect's office before the new moon, or my father loses his exemption. Nobody here is making me. Rome is.

Sophia. There it is, laid out without either of you trying. "Must" reaches for an obligation that comes from inside the speaker — my own judgment, my own authority, my own sense of what's owed. "Have to" reaches outward, to a rule that exists whether or not the speaker agrees with it. Philo telling himself he must return that scroll is Philo's own conscience talking. Marcos having to register with the prefect is Rome's law talking, with Marcos merely reporting it.

Demetria. So they end up meaning almost the same thing, in practice.

Sophia. Almost — until you make them negative, where they stop agreeing with each other entirely, and every one of you will get this wrong at least once before it sticks. "You must not touch a scroll with oiled fingers." Forbidden. Absolutely not permitted, by me, right now. Now: "You don't have to bring your own ink — the library keeps a full store of it." Not forbidden at all. Simply not required. The opposite of an obligation is not the same shape as the opposite of a permission, and "must not" and "don't have to" are not mirror images of one another, however much they look it at first.

Marcos. (muttering) I have gotten this wrong in actual Latin, and now I'll get it wrong in Greek too, out of consistency.

Philo. We keep an older, heavier cousin of "must" for exactly the weightiest obligations — the ones that aren't really debatable. Every line of the commandments is built on it. Not "you must not steal." "You shall not steal." Nobody I know says "shall" about anything smaller than that.

Sophia. That's exactly the right instinct. "Shall" used to be the ordinary word English reached for, for both plain obligation and the simple future, long before "must" and "will" crowded most of it out of daily speech. What's left of it now mostly survives in exactly the places you'd expect an older, more formal form to survive — law, scripture, solemn promises, and the one polite offer nobody's quite replaced: "Shall we begin?"

Sophia. Obligation is only one of the things a modal can be doing, though. Watch this: Demetria, hide something of mine somewhere in this room while my eyes are closed, and the rest of you help me find it using nothing but modal verbs.

(a scroll case vanishes behind a stack of tablets; Sophia keeps her eyes shut, counting slowly)

Sophia. Philo, where is it?

Philo. It can't be on the shelf — I was standing in front of the shelf the whole time and nothing moved. It might be behind the tablets Marcos was sorting.

Marcos. It must be there, then — Demetria was standing closest to my desk the entire time, and nowhere else.

Sophia. (opening her eyes, walking straight to the tablets) Correct — and notice what all three of you just did without being told to. None of you knew, the way you know your own name. You were reasoning from evidence to a conclusion, and the modal you reached for told the rest of us exactly how confident that conclusion was. "Can't" — Philo was certain enough to rule a place out entirely. "Might" — a real possibility, no better than that. "Must" — Marcos was about as sure as a person can be without having actually seen it happen.

Sophia. One more family, and then we'll have covered the ground modals cover in the present tense before we go anywhere near the past. Marcos, ask me properly for something.

Marcos. Can I leave early today? My father's expecting me at the harbor.

Sophia. You can, this once, since the harbor rarely waits for anyone. Though if you'd asked a stranger, or someone considerably above your station, "may I" carries itself with a good deal more formality than "can I" does — and "could I," softer still, is the one you reach for when you're not entirely sure the answer will be yes.

Sophia. All of that has lived entirely in the present. Now push every single thing we've just said backward into the past, and the shape of the sentence changes in exactly one way, every time: the modal, then have, then the past participle. Never musted. Never coulded. The modal never moves; everything after it does the work.

Sophia. Return to Philo's scroll, and suppose — badly, hypothetically — that it never came back at all.

Philo. (wincing) Must you.

Sophia. I must. "You should have returned the scroll last night." That's regret, or a scolding, aimed at something that didn't happen but was owed. "You must have forgotten." A confident guess about the past, built the same way "must" built one about the present a moment ago, just reaching one day further back. "You can't have taken it — I saw it on the shelf myself this morning." Impossible, ruled out by evidence, same as "can't" a moment ago, except now the evidence points at yesterday instead of today.

Demetria. And if nobody's sure at all?

Sophia. Then you soften it the same way you would in the present. "You might have left it in the east wing." A real possibility, no more claimed than that. And one shape left, the strangest of the family: "You needn't have rushed to finish your translation — the deadline was extended this morning, and nobody told you in time." An effort that was made, and turned out not to have been required at all. Not forbidden, not exactly wasted — just unnecessary, after the fact.

Sophia. (pausing over her own sentence) "You must have been tired, to have forgotten something you never forget." Listen to what "been" is doing in there. You've met it before.

Philo. Lesson Three. "To be" — identity, predication, location, an auxiliary carrying another verb, and simple existence.

Sophia. That one. A linking verb, describing a state rather than an action — the very thing we sat with three lessons ago — except this time it's climbed onto the back of a modal to get here. The scaffolding around it changed. The job it's doing did not.

Philo. There's nothing quite like any of this in the tongue I grew up praying in. Biblical Hebrew doesn't keep a family of little words sitting in front of the verb the way you've laid these out. If something should happen, or you're being urged toward it, the verb itself bends into a different mood to say so — the form changes, rather than a separate word being set in front of it. Obligation, wish, and command each get folded straight into the verb, not handed a modal of their own to carry them.

Sophia. Which is worth sitting with, all of you — English didn't have to solve this problem with a family of separate little words either. It's one solution among several a language can reach for, not the only shape the idea of "must" or "might" could ever take. We've simply inherited this one, and now, four broken promises later, you finally have it in full.

Marcos. So — five lessons from now you'll finally teach us something else you keep promising?

Sophia. (closing the tablet, allowing herself exactly one small smile) Next lesson, and I intend to actually mean it this time: adverbs. Not merely the ones trailing after a verb, the way you were taught as children — wait until you see what they do to an adjective, to each other, and on occasion to an entire sentence at once.