Five words on a signpost at the top of a boat ramp. SLIPPERY WHEN WET OR ICY. Ice is slippery, and whoever ordered the sign knew that as well as anybody who would ever read it. So why the last two words?

Being told what you already know is not a neutral event. In 1975 the philosopher Paul Grice set out rules people follow in conversation without being taught. Among them, the maxim of quantity: say as much as is needed, no more. Break it and the listener goes looking for the reason.

Anyone who watches true crime has heard it in the suspect interview where the account arrives with too much in it: the route named street by street, timings to the minute, an unprompted remark about what was on the radio. Whether the person was guilty is a separate issue. The extra words register.

Three reasons are available. Whoever is doing the telling thinks you need it. They're anxious, and their words run on ahead of the point. Or the words were for somebody who isn't you.

Defensive writing is what institutional nerves look like when posted in public. But nerves have an object. The institution isn't anxious in general; it's anxious about one unlikely future — a claim, a hearing, somebody with a lawyer — and it shapes the words to cover itself in that room. Follow the nerves and you find who the words are for.

So the words aren't there in case a reader is unclear on ice. They're there so they can be read aloud later, in a room with a stenographer, by someone establishing that the hazard was disclosed. Standing at the top of the ramp, you are a bystander to a message addressed elsewhere.

People feel that even when they can't name it, and the response usually isn't offense. It's a discount. The notice goes into a category, not for me, and every subsequent notice from the same institution arrives pre-filed there.

When it is offense, it has a name. Jack Brehm called it reactance in 1966: the push-back people generate when they feel their own competence being managed. Anyone who assumes the sign is addressed to them can only conclude that it thinks they don't know what ice does.

California ran this at scale.

Proposition 65 required a warning anywhere a listed chemical might come in contact with a person — breathed in, swallowed, or taken up through skin — and the warning it produced said close to nothing: this area can expose you to chemicals known to the State of California to cause cancer. It went up on parking garages and hotel lobbies, until the placard carried the same weight on a can of paint as the label on a drum of solvent.

Why is it only California that knows about the threat?

The chemistry doesn't change at the state line. The warning tells you something about the institution that produced it, not much about the thing in front of you.

In 2018 the state's Office of Environmental Health Hazard Assessment rewrote the rules to force the warnings to carry more specific information: name at least one of the chemicals, say the product can expose you to, and link to a page describing what it does to a body. Better.

Above the treeline in New Hampshire's White Mountains, the Forest Service has kept the same sign standing since the 1920s.

STOP. The area ahead has the worst weather in America. Many have died there from exposure, even in the summer. Turn back now if the weather is bad.

Nothing in it is hedged, nothing held in reserve for a courtroom. It names the consequence in the plainest words and then hands the decision back. A running list of deaths on the Presidential Range counts 178 since 1849, and more than half of the ones caused by exposure happened between June and September. The sign respects you enough to frighten you accurately.

The usual explanation for how signs got like this is a lawsuit, and it's wrong. Nearly everyone can half-recall the case; almost nobody can state its facts. The car was parked. The woman in the passenger seat was seventy-nine, the burns took skin grafts and eight days in hospital to close, and she asked for the medical bills — twenty thousand dollars — and was offered eight hundred. The cup already had a warning printed on it; what the jury found was that it was too small to do any good. The sentence everyone thinks that verdict invented was sitting there before anybody sued, protecting nobody.

California's Proposition 65 warnings weren't a court's doing either: sixty-three percent of voters passed them in 1986, and they were up on the walls and the sides of paint cans by 1988.

We assume it was the legal department's idea, and it may well have been. Counsel was asked to reduce exposure and did exactly that, competently. But the sentence didn't stop at counsel's desk. Before it reached the sign-maker it will have passed a facilities manager and a risk review, and every desk it crossed checked it against the same question: does this cover us? Nobody in the chain was employed to ask what a person at the top of the ramp gets from reading it.

Every qualification says: we thought of an objection. Every disclaimer says: we are protecting ourselves from a future interpretation. Every unnecessary phrase says: there is another person in this room whose approval matters, and that person is not you.

The opposite of a defensive sentence isn't a warm one. It's a sentence with nobody standing between the writer and the reader. To find one, look for an organization writing down something that costs it dearly, because an admission is the one kind of sentence a third party can't be the point of. It takes something from the writer, and the only person it gives anything to is the one reading it.

Riverford Organic Farmers puts a letter in the vegetable boxes it delivers, written by the farmer who started the company, and has done for decades. It's where customers learned that the Devon butternut squash kept failing to ripen and disappointing in the kitchen, so the squash in the box is grown in France now. After 250 miles on a lorry (it's a British farm), he reckons it still has a smaller footprint than the Devon crop used to.

Fairphone published the full cost breakdown of its second handset in 2015, and it publishes the places its own promise breaks: smelters that blend its Fairtrade gold back into the ordinary supply because its volumes are too small to be worth separating.

Neither has a second audience — no room in either for somebody who isn't the reader.

There's a sentence with your organization's name on it in front of somebody right now: on a door, in a confirmation email, on a page nobody has opened since it was approved. Read it and count the clauses that exist for a person who will never stand in front of it.

Then ask:

Who is standing here now, and what do they need to know?

The mountain sign has been up for a century, on ground that kills people with cold, and has never been softened. There's no or icy anywhere in it.