--- title: "If... then..." and its traps — a lesson of Mova's school · trees and pragmatics description: «"If... then..." and its traps», a lesson of the world course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: "If it rains, the grass gets wet" is a one-way street: rain leads to wet grass. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [World](https://md.mova.elamur.ai/free/en/corpora/school/world/) / "If... then..." and its traps # "If... then..." and its traps Lesson 184 of the world course of Mova's primary school: 22 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/world/184-if-then-and-its-traps/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/0/) — "If it rains, the grass gets wet" is a one-way street: rain leads to wet grass. - [1](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/1/) — It doesn't run backwards, because wet grass can also come from a sprinkler, dew or a dog. - [2](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/2/) — Two traps catch people all the time: running the "if" backwards ("the grass is wet, so it rained") and "not the first, so not the second" ("my cat isn't a dog, so it's not an animal"). - [3](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/3/) — One move is always safe: if every square has 4 sides, then a shape with 3 sides is not a square. - [4](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/4/) — Leo: "Bro, it has three sides. - [5](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/5/) — It's a triangle. - [6](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/6/) — It's not undercover." - [7](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/7/) — Even perfect steps give a wrong answer if the starting rule is false: "if the dog barks, someone's at the door" fails the day he barks at a squirrel. - [8](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/8/) — In everyday deals, "if you finish your work, you can play" usually means "only if you finish". - [9](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/9/) — Lucas knows the strict logic; the teacher still hands him a worksheet. - [10](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/10/) — "If it rains, the grass is wet" does not mean "if the grass is wet, it rained"; sprinklers, dew and dogs wet grass too. - [11](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/11/) — Running an "if" backwards is a mistake grown-ups call affirming the consequent. - [12](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/12/) — "If it's a dog, it's an animal" says nothing about things that aren't dogs: cats, horses and people are animals too. - [13](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/13/) — If all squares have 4 sides, then any shape without 4 sides is not a square; this move is always right. - [14](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/14/) — A shape with 4 sides is not always a square: rectangles and kites have 4 sides too. - [15](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/15/) — "If you're in Year 5, you swim on Tuesdays" tells you about Year 5, not about everyone who swims on Tuesday. - [16](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/16/) — "If it's sunny, we'll go to the park" says nothing about rainy days, so going anyway is not breaking the promise. - [17](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/17/) — In strict logic "if A, then B" says nothing about what happens when A is false; in everyday deals like "if you finish, you can play", people usually mean "only if". - [18](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/18/) — A correct step from a false rule can give a wrong answer: a dog that barks at squirrels doesn't prove someone is at the door. - [19](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/19/) — Studying makes passing more likely, but passing doesn't prove you studied: an easy test is another reason. - [20](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/20/) — "If you are under 12, you must wear armbands" only talks about under-12s; older swimmers may still choose to wear them. - [21](https://md.mova.elamur.ai/free/en/corpora/school/world/184-if-then-and-its-traps/21/) — Words people use: "bruv" and "bro" (London, young people) mean mate; "mardy" (Midlands, North) means sulky; "wee" (Scotland) means small; "aye" (Scotland, North) means yes; "Roblox" is a computer game; "my bad" means "my mistake". - ← previous: [Sounds right, but is wrong](https://md.mova.elamur.ai/free/en/corpora/school/world/183-sounds-right-but-is-wrong/) - next →: [Some, all, none and "not all"](https://md.mova.elamur.ai/free/en/corpora/school/world/185-some-all-none-and-not-all/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/corpora/school/world/)