An argument is made up of one or more statements, ideas, or claims that are used to reach a logical conclusion. The purpose of an argument is to explain, support, or persuade someone by providing reasons for a belief or understanding. Arguments follow a series of logical steps to determine whether a conclusion is true or acceptable.
The process of creating or presenting arguments, called argumentation, can be studied in three main ways: through logic, dialectics, and rhetoric.
In logic, arguments are often written using special symbols or codes instead of everyday language. A logical argument is a set of statements where one statement is said to follow from the others through valid reasoning that keeps truth consistent from the starting points to the conclusion. This way of thinking about arguments is important in fields like mathematics and computer science. Logic studies how reasoning works in arguments and sets rules to evaluate them. Deductive arguments can be valid or sound. A valid argument means the conclusion must be true if the starting points are true, even if those starting points are not actually true. A sound argument has true starting points and leads to a true conclusion. Inductive arguments, on the other hand, are not certain. They can be stronger or weaker, meaning the conclusion is more or less likely to be true. The way people judge inductive arguments may depend on factors other than truth, such as how convincing certain claims are or how good the ideas in an argument are.
In dialectics, an argument is a way people use spoken language to try to solve or discuss differences in opinions between groups. In rhetoric, arguments are connected to the time and place where they are made, and they are judged not only by the people involved but also by an audience. In both dialectics and rhetoric, arguments are expressed using everyday language. For many years, philosophers and speakers have created lists of argument types where ideas and conclusions are linked in ways that can be changed or challenged.
Etymology
The Latin word "arguere" means to make bright, enlighten, make known, or prove. It comes from an ancient language called Proto-Indo-European, where the word was "argu-yo-" and was formed by adding a part to the end of "arg-" (which means to shine or be white).
Formal and informal
Informal arguments, as studied in informal logic, are spoken in everyday language and used in daily conversations. Formal arguments, studied in formal logic (also known as mathematical logic today), are written in a special kind of language. Informal logic focuses on how people argue, while formal logic focuses on how conclusions are reached from facts. Informal arguments may not always clearly show how ideas connect. The way statements, reasons, and conclusions relate may not be obvious and needs to be explained carefully.
Standard logical account of argument types
There are different types of arguments in logic, with deductive and inductive being the most well-known. An argument includes one or more premises and one conclusion. Each premise and the conclusion are statements that can be true or false, but not both. These truth values influence the terms used to describe arguments.
A deductive argument claims that the conclusion must be true if the premises are true. If the premises are true, the conclusion cannot be false without creating a contradiction. For example, if A equals B and B equals C, then A must equal C. Deductive arguments are sometimes called "truth-preserving" because the truth of the premises ensures the truth of the conclusion. For instance, if a premise states "Bats can fly" (true) and another premise says "All flying creatures are birds" (false), the conclusion "Bats are birds" (false) would not follow logically if the premises were true.
Deductive arguments can be valid or invalid. An argument is valid if it is impossible for the premises to be true and the conclusion false in any situation. Validity depends on the logical structure of the argument, not the actual truth of the premises or conclusion. A valid argument can still have false premises, making the conclusion uncertain even if the structure is correct.
Logic studies the structures that make arguments valid. An argument is valid if the conclusion is true whenever the premises are true. An argument can be shown invalid by providing a counterexample with the same structure but true premises and a false conclusion. This is called a "counterargument" in informal logic.
The structure of an argument can be represented using symbols. A valid argument has a corresponding conditional statement that is always true. A statement is a logical truth if it is true in all situations. Logical truths can be proven by showing they are tautologies (statements that are always true) or through logical proofs.
The conclusion of a valid argument is not necessarily true unless the premises are true. If the conclusion is a necessary truth (true in all situations), it does not depend on the premises.
In some cases, a counterexample can show an argument is invalid. For example, if the premises are "Some men are hawkers" and "Some hawkers are rich," the conclusion "Some men are rich" might not follow logically, depending on the premises.
Deductive reasoning follows established rules, but some invalid arguments can still seem persuasive, like inductive arguments. Inductive arguments use probability rather than certainty. For example, if the United States has the largest military budget (true), it is likely to remain so in the future (true). Inductive arguments are strong if the premises make the conclusion probable and the premises are true. A strong argument with true premises is called "cogent."
Non-deductive logic includes reasoning where the premises support the conclusion but do not guarantee it. Examples include statistical syllogisms and induction. Inductive arguments are cogent if the premises make the conclusion likely and are true. Mathematical induction is not a form of inductive reasoning. The challenge of ensuring non-deductive reasoning is reliable is known as the "problem of induction."
Defeasible arguments and argumentation schemes
In modern argumentation theories, arguments are seen as ways to reach a conclusion from facts, but these ways can change if new information is added. This change happens because new evidence or opposing ideas might show that the original facts no longer support the conclusion. This type of reasoning is called defeasible reasoning. For example, consider the famous Tweety example:
This argument is reasonable unless new information shows it is an exception. If Tweety is a penguin, the conclusion that it can fly is no longer correct. Defeasible arguments rely on general rules that usually work but can be exceptions in some cases.
To understand and evaluate this type of reasoning, we need to use both logical rules (which show how to accept a conclusion based on facts) and rules that explain how a fact can support a conclusion (whether it is reasonable to draw that conclusion).
Argumentation schemes are tools used to describe and judge the strength or weakness of defeasible arguments. These schemes are common patterns of reasoning that combine how ideas relate to each other, types of reasoning, and logical rules. A typical example is the argument from expert opinion, which uses two facts to support a conclusion.
Each scheme includes specific questions that help evaluate whether an argument is reasonable. These questions are standard ways to challenge or test the validity of an argument.
By analogy
An argument by analogy is a type of reasoning that moves from a specific fact in a premise to a similar specific fact in the conclusion. For example, if we know that Plato was mortal and Socrates was similar to Plato in other ways, then saying that Socrates was mortal is an example of argument by analogy. This type of reasoning uses the specific fact that Plato was mortal in the premise to support the similar specific fact that Socrates was mortal in the conclusion.
Other kinds
Other types of arguments may follow different or extra rules to prove they are correct. For example, philosopher Charles Taylor explained that transcendental arguments use a series of important reasons to show why something must be true because of how it connects to our experiences. Nikolas Kompridis said there are two kinds of arguments that can be wrong: one that focuses on whether something is true, and another that explores new possibilities by looking at how the world changes over time (world disclosure). Kompridis noted that the French philosopher Michel Foucault was a well-known supporter of this second type of argument.
World-disclosing arguments are a group of philosophical arguments that, according to Kompridis, use a method to uncover aspects of a larger understanding of reality or culture—what he calls a "world" in a deep, fundamental sense. These arguments aim to make clearer or change the unspoken knowledge and the hidden structure that an argument relies on, which Kompridis refers to as the "logical space."
Explanations
Arguments try to show whether something is true, should be true, or will happen. Explanations try to show why or how something happens. For example, if Fred and Joe discuss whether Fred’s cat has fleas, Joe might say, “Fred, your cat has fleas. Look, the cat is scratching now.” This is an argument because Joe is trying to prove the cat has fleas. However, if Joe asks, “Why is your cat scratching?” and Fred replies, “Because it has fleas,” this is an explanation that helps understand the reason for the scratching.
Both the argument and the explanation depend on knowing general facts: (a) fleas often cause itching, and (b) people scratch to relieve itching. The difference is in the goal: an argument tries to decide if a statement is true, while an explanation tries to clarify why an event happens. By grouping the specific event (the cat scratching) with the general rule that “animals scratch when they have fleas,” Joe no longer needs to wonder why the cat is scratching. Arguments deal with whether something is true, and explanations deal with why something happens. In the argument, the statement “Fred’s cat has fleas” is something to be debated, but in the explanation, it is assumed to be true and only needs a reason.
Arguments and explanations are often used in similar ways in communication. This can make it hard to think critically about claims. There are several reasons for this difficulty.
Explanations and arguments are studied in the field of information systems to help understand how people accept systems that use knowledge. Some types of arguments may match certain personality traits, making it easier for people to accept these systems.
Fallacies and non-arguments
Fallacies are types of arguments or statements that have incorrect reasoning. One kind of fallacy happens when a word that usually shows a conclusion is used to connect two separate ideas. In English, words like "therefore," "so," "because," and "hence" often separate the reasons from the conclusion in an argument. For example: "Socrates is a man, all men are mortal, therefore Socrates is mortal" is an argument because the conclusion "Socrates is mortal" comes from the earlier statements. However, "I was thirsty and therefore I drank" is not an argument, even though it looks like one. This is because the statement "I drank" does not logically follow from "I was thirsty." The word "therefore" here shows the reason, not that the conclusion follows from the reason.
Elliptical or ethymematic arguments
Sometimes an argument is not strong because it is missing a key point. This missing point is called an elliptical or enthymematic argument. People may leave out a necessary point if it is commonly known and they do not want to mention something obvious. Example: All metals expand when heated, so iron will expand when heated. The missing point is: Iron is a metal. However, an argument that seems strong may actually be missing a hidden assumption. Example: A witness said, "Nobody came out the front door except the milkman, so the murderer must have left by the back door." The hidden assumptions are: (1) the milkman was not the murderer, (2) the murderer left, (3) the murderer left through a door, (4) not through a window or a hole in the roof, and (5) there are only front and back doors.
Argument mining
Argument mining is the process of using computer programs to automatically find and identify parts of arguments in written or spoken language. These parts include the reasons given (premises), the main point being made (conclusions), the type of argument used (argument scheme), and how the main argument connects to supporting ideas or opposing views within a discussion.