Argument

[1] The purpose of an argument is to give reasons for one's conclusion via justification, explanation, and/or persuasion.

Arguments are intended to determine or show the degree of truth or acceptability of another statement called a conclusion.

[4] In logic, an argument is usually expressed not in natural language but in a symbolic formal language, and it can be defined as any group of propositions of which one is claimed to follow from the others through deductively valid inferences that preserve truth from the premises to the conclusion.

This logical perspective on argument is relevant for scientific fields such as mathematics and computer science.

[6] The standards for evaluating non-deductive arguments may rest on different or additional criteria than truth—for example, the persuasiveness of so-called "indispensability claims" in transcendental arguments,[7] the quality of hypotheses in retroduction, or even the disclosure of new possibilities for thinking and acting.

[8] In dialectics, and also in a more colloquial sense, an argument can be conceived as a social and verbal means of trying to resolve, or at least contend with, a conflict or difference of opinion that has arisen or exists between two or more parties.

Since classical antiquity, philosophers and rhetoricians have developed lists of argument types in which premises and conclusions are connected in informal and defeasible ways.

The rational structure—the relationship of claims, premises, warrants, relations of implication, and conclusion—is not always spelled out and immediately visible and must be made explicit by analysis.

Each premise and the conclusion are truth bearers or "truth-candidates", each capable of being either true or false (but not both).

If we assume the premises are true, the conclusion follows necessarily, and it is a valid argument.

[1] An argument is formally valid if and only if the denial of the conclusion is incompatible with accepting all the premises.

A statement form can be shown to be a logical truth by either (a) showing that it is a tautology or (b) by means of a proof procedure.

Some examples: In the above second to last case (Some men are hawkers ...), the counter-example follows the same logical form as the previous argument, (Premise 1: "Some X are Y."

For example, given that the military budget of the United States is the largest in the world (premise=true), then it is probable that it will remain so for the next 10 years (conclusion=true).

Defeasibility means that when additional information (new evidence or contrary arguments) is provided, the premises may be no longer lead to the conclusion (non-monotonic reasoning).

For instance we consider the famous Tweety example: This argument is reasonable and the premises support the conclusion unless additional information indicating that the case is an exception comes in.

Defeasible arguments are based on generalizations that hold only in the majority of cases, but are subject to exceptions and defaults.

[13] A typical example is the argument from expert opinion, shown below, which has two premises and a conclusion.

[14] Each scheme may be associated with a set of critical questions, namely criteria for assessing dialectically the reasonableness and acceptability of an argument.

For example, philosopher Charles Taylor said that so-called transcendental arguments are made up of a "chain of indispensability claims" that attempt to show why something is necessarily true based on its connection to our experience,[15] while Nikolas Kompridis has suggested that there are two types of "fallible" arguments: one based on truth claims, and the other based on the time-responsive disclosure of possibility (world disclosure).

[17] World-disclosing arguments are a group of philosophical arguments that according to Nikolas Kompridis employ a disclosive approach, to reveal features of a wider ontological or cultural-linguistic understanding—a "world", in a specifically ontological sense—in order to clarify or transform the background of meaning (tacit knowledge) and what Kompridis has called the "logical space" on which an argument implicitly depends.

Certain argument types may fit better with personality traits to enhance acceptance by individuals.

[21] Fallacies are types of argument or expressions which are held to be of an invalid form or contain errors in reasoning.

One type of fallacy occurs when a word frequently used to indicate a conclusion is used as a transition (conjunctive adverb) between independent clauses.

This is referred to as an elliptical or enthymematic argument (see also Enthymeme § Syllogism with an unstated premise).

On the other hand, a seemingly valid argument may be found to lack a premise—a "hidden assumption"—which, if highlighted, can show a fault in reasoning.