Argument

An argument is a way of giving reasons to support an idea or belief. It uses one or more premises—sentences or statements—to reach a logical conclusion. The goal of an argument is to explain or persuade someone why an idea makes sense.

Arguments can be studied in different ways. In logic, they are sometimes written in a special formal language to see if the conclusion must be true based on the premises. This kind of thinking is important in mathematics and computer science. There are two main types of logical arguments: deductive and inductive. In deductive arguments, if the premises are true, the conclusion must be true. In inductive arguments, the conclusion is likely to be true but not completely certain.

Arguments are also used in everyday conversations to help solve disagreements between people. From a dialectical view, arguments help people discuss and work through their differences. From a rhetorical view, arguments depend on the situation and audience, and they are judged on how well they fit the context and persuade listeners. Both of these views use everyday language instead of formal symbols.

Etymology

The word "argument" comes from a Latin word, arguere. This means to make something clear or prove it. The Latin word comes from an older language called Proto-Indo-European. In that language, it means "to shine" or "to be white."

Formal and informal

Further information: Informal logic and Formal logic

Informal arguments, studied in informal logic, use everyday language for regular talks. They help us share and understand ideas with others. Formal arguments, studied in formal logic, use special languages to show how ideas link together. Informal arguments may not always be clear, so we sometimes need to find the hidden connections between ideas.

Standard logical account of argument types

There are different kinds of arguments in logic. The two most well-known types are deductive and inductive. An argument has one or more premises and one conclusion. Each premise and the conclusion can be true or false.

Deductive arguments

Main article: Deductive argument

A deductive argument says that if the premises are true, the conclusion must be true. For example, if we know that A=B and B=C, then we can conclude that A=C. Deductive arguments are called "truth-preserving" because, if the premises are true, the conclusion has to be true too.

Validity

Main article: Validity (logic)

A deductive argument is valid if it is impossible for the premises to be true while the conclusion is false. Validity looks at how the premises and conclusion are connected. An argument is valid if the conclusion follows logically from the premises.

Soundness

Main article: Soundness

An argument is sound when it is valid and its premises are true. This means the conclusion is also true.

Inductive arguments

Main article: Inductive reasoning

An inductive argument says that the premises make the conclusion likely to be true. For example, if the military budget of the United States is the largest in the world, it is probable that it will stay that way for the next 10 years. Inductive arguments can be strong or weak depending on how well the premises support the conclusion. A strong inductive argument with true premises is called cogent.

Defeasible arguments and argumentation schemes

In modern thinking about arguments, our reasons for a conclusion can change if we learn new facts. This idea is called defeasibility.

For example, imagine Tweety the bird. Birds can usually fly, so we might think Tweety can fly too. But if we later find out Tweety is a penguin, that changes things — penguins don’t fly!

Defeasible arguments are based on general ideas that usually work, but might not always. To check if these arguments make sense, we use special patterns called argumentation schemes. These help us see if an argument is strong or weak. One common pattern is when we listen to an expert’s opinion. Each pattern comes with questions we can ask to test the argument.

By analogy

An argument by analogy is a way of thinking that moves from one idea to another that is similar. It uses what we know about one thing to guess what might be true about another thing that is alike in some ways. For example, if we know that Plato was a person who lived and died, and Socrates was similar to Plato, we might think that Socrates also lived and died. This works because the argument starts with a true fact about Plato and uses it to suggest a similar fact about Socrates.

Other kinds

Different types of arguments have special rules for what makes them strong or true. For example, the philosopher Charles Taylor talked about something called "transcendental arguments." These arguments try to show why something must be true by linking it to our own experiences.

Another thinker, Nikolas Kompridis, described two kinds of arguments that can change over time. One kind focuses on what we believe is true, while the other helps us see new possibilities in the world around us. The famous philosopher Michel Foucault supported this second kind of argument.

World-disclosing

Main article: World disclosure

World-disclosing arguments are special types of arguments that help us understand deeper meanings and ideas about our world. They show us new ways of thinking and can change how we see things we usually take for granted. This approach helps clarify hidden knowledge and expands the ideas we use when we make arguments.

Explanations

Main article: Explanation

Arguments and explanations are two different ways we think about things. An argument tries to show that something is true. For example, if Joe tells Fred, "Your cat has fleas because it’s scratching," he is making an argument. He wants Fred to believe the cat has fleas.

An explanation tries to show why or how something happens. If Joe asks, "Why is your cat scratching?" and answers, “Because it has fleas,” he is giving an explanation. He is helping Fred understand the reason behind the scratching.

Both arguments and explanations can sound similar, so it can be hard to tell them apart. People sometimes mix them up or use the same words for both. Knowing the difference helps us think more clearly.

Fallacies and non-arguments

Main article: Fallacy

Fallacies are mistakes in thinking that can make an argument confusing. Sometimes, people use words like therefore, so, because, and hence in the wrong way. For example, saying "Socrates is a man, all men are mortal, therefore Socrates is mortal" is a good argument because it makes sense. But saying "I was thirsty and therefore I drank" is not an argument because it does not show a clear reason why drinking follows from being thirsty. The word therefore here just means "for that reason" and not that one thing surely leads to another.

Elliptical or ethymematic arguments

Sometimes, an argument might not seem strong because it is missing a piece of information—a premise. Adding this missing piece can make the argument better. This kind of argument is called an elliptical or enthymematic argument. For example, someone might say, "All metals expand when heated, so iron will expand when heated." The missing piece here is, "Iron is a metal."

On the other hand, what looks like a good argument might actually have a hidden idea that, when shown, reveals a problem in the thinking. For example, a witness might say, "Nobody came out the front door except the milkman, so the person who did something wrong must have left by the back door." This hides several ideas: that the milkman wasn't the person who did something wrong, that the person has already left, that they left by a door, and that there are only two doors—the front and the back.

Argument mining

Argument mining uses computer programs to find and understand arguments in writing. It looks for the reasons given, the main point, and how the parts of the argument fit together.