In logic we often talk about the logical properties of statements and how one statement is related to another. So what is a statement?
L02.1 What is a statement?
There are three main sentence types in English:
- Declarative sentences are used for assertions, e.g. “He is here.”
- Interrogative sentences are used to ask questions, e.g. “Is he here?”
- Imperative sentences are used for making requests or issuing commands, e.g. “Come here!”
For present purposes, we shall take a statement to be any declarative sentence. A declarative sentence is a complete and grammatical sentence that makes a claim. So here are some examples of statements in English :
- Snow is white.
- The moon is made of green cheese.
- Everyone is here.
- Whatever will be, will be.
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As you can see, statements can be true or false, and they can be simple or complex. But they must be grammatical and complete sentences. So these are not statements :
- The United Nations [ A proper name, but not a sentence ]
- Bridge over troubled waters. [ Not a complete sentence ]
- Come here right now! [ A command that is not a complete sentence making a claim ]
- Will you be available on Tuesday or Wednesday? [ A question ]
- HJGAS&*^@#JHGKJAS*&^*!@GJHGAA*&S [ Ungrammatical ]
There is an easy test to decide whether something is a statement in English. Suppose you have a sentence φ and you add “it is true that” to the front. If the resulting expression is grammatical, then φ is a statement. Otherwise it is not.
So for example, φ might be “bridge over troubled waters”. We append “it is true that” to the front, and end up with “it is true that bridge over troubled waters.” But this expression is not grammatical. So “bridge over troubled waters” is not a statement. However, “I am like a bridge over troubled waters” is a statement, because “it is true that I am like a bridge over troubled waters” is grammatical.
Question 1. How about the following? Are these statements?
- One plus one equals three.
- Can you come to the party please?
- If it rains then the street will be wet.
- Come here!
- A chicken is a song that weighs ten tons.
- All statements are true.
- It is true that it is raining.
- I am ordering you to stop talking in class.
- We all feel very sorry for you.
Question 2. Rewrite these utterances or headlines as statements.
- Yes. A false statement.
- A question and not a statement.
- “It is true that AJHGJH&#HJGJ” is not grammatical. So it is not a statement.
- Yes. A conditional statement about what happens when it rains.
- Although statements are often used to convey information, they can also be used for other purposes as well, such as expressing sympathy.
- Not a statement but a command.
- It is a complete and meaningful sentence, even if what it says is silly and must be false since a chicken is not a song. But it is still a statement.
- It is a (false) statement about statements.
- Yes. A statement.
- Yes. It is actually both a statement and a command at the same time. The statement makes a claim about the command that is being issued at the same time the statement is made. This example tells us that some imperative sentences are also declarative.
- Inflation is rising.
- Kidnapper says that the boy will die if no ransom is paid.
- Scientists say that coffee is good for your health.
- Some paintings have been stolen from The Presidential Palace. [This is probably better than “All paintings have been stolen from The Presidential Palace.”]
- If I do not get any money, I will not work.
- Dr. Joe Lau
Department of Philosophy, University of Hong Kong
- Dr. Jonathan Chan
Department of Religion and Philosophy, Baptist University of Hong Kong
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