What Is a Premise? | Definition & Examples

Premises are the key points made in support of an argument’s conclusion. They play a crucial role in all forms of reasoning.

Premise in argumentation example
Premise: All even numbers are divisible by 2.

Premise: 4 is divisible by 2.

Conclusion: Therefore, 4 is an even number.

“Premise” can also refer to the background situation that sets up a story or joke. This more colloquial use of the term is common in discussions of literature and the performing arts.

What is a premise?

A premise is a statement that expresses the logical basis for an argument’s conclusion.

In formal logic, premises play a crucial role in syllogisms, a form of argument in which two premises precede a conclusion. Premises also play an important role in informal arguments, which require at least one but sometimes have several premises.

The word “premise” can also refer to a scenario that sets the stage for a story or punchline (e.g., “The premise of Star Wars is the struggle between the Rebel Alliance, which aspires to restore democracy, and the Galactic Empire, which seeks to enforce its authoritarian control over the galaxy”).

“Premise” can be used in sentences as a noun, representing the foundational element upon which an argument or theory is based (e.g., “The premise of the argument was that all humans are inherently equal”). It can also be used as a transitive verb to describe the act of establishing a premise (e.g., “I premised my theory on the assumption of universal human rights”).

Premises in arguments

Premises serve as the foundation of arguments across various forms of reasoning, including deductive reasoning, inductive reasoning, and abductive reasoning.

Arguments that rely on deductive reasoning are called formal arguments. They follow a strict structure in which broad premises are presented to prove a specific conclusion with logical certainty.

Premises in deductive reasoning example
Premise: All mammals breathe air.

Premise: Whales are mammals.

Conclusion: Therefore, whales breathe air.

In contrast, informal arguments typically rely on inductive reasoning. In these arguments, specific premises provide support for a broad conclusion, demonstrating that it is highly likely to be true.

Premises in inductive reasoning example
Premise: Every observed crow is black.

Conclusion: It is likely that all crows are black.

Abductive reasoning can also be used in informal arguments. Here, premises are used to generate the most plausible cause of a specific instance or phenomenon.

Premises in abductive reasoning example
Premise: It’s suddenly very dark outside.

Conclusion: It’s probably going to rain.

Note
In practice, informal arguments typically lack the structure seen in examples. Their premises are often implicit, and the order of presentation is flexible.

Premises in syllogisms

Premises are often given specific labels according to the roles they play in syllogisms (i.e., forms of deductive arguments).

Conditional premises

Conditional premises (used in hypothetical syllogisms, or conditional syllogisms) express an if–then relationship between two statements, where one statement logically implies another.

Conditional premise example
If it rains, then the ground will be wet.

Disjunctive premises

Disjunctive premises (used in disjunctive syllogisms) affirm or deny one of two mutually exclusive (either–or) options.

Disjunctive premise example
The book is either on the table or off the table.

Categorical syllogisms

Categorical syllogisms involve reasoning based on relationships between categories or classes of things (e.g., “All birds have feathers” makes a claim about the relationship between birds and feathers). Several terms are used to describe the types of premises used in categorical syllogisms:

  • Major premise: Asserts a broad principle about a category (e.g., “All mammals are warm-blooded.”)
  • Minor premise: Applies the principle from the major premise to a particular case (e.g., “Whales are mammals.”)
  • Negative premise: Denies that a relationship or characteristic exists (e.g., “No reptile has fur.”)
  • Affirmative premise: Asserts that a relationship or characteristic exists (e.g., “Trees produce oxygen.”)
  • Universal premise: Presents a claim about all members of a category (e.g., “All rectangles have four sides.”)
  • Particular premise: Presents a claim about some, but not all, members of a category (e.g., “Some fish live in saltwater.”)
Note
Premises often fit multiple categories. For example, a premise can be a major premise while also being affirmative and universal (e.g., “Each planet orbits a star”). The best term to use for a given premise depends on the context of the discussion.

Frequently asked questions about premises

What is the plural form of premise?

The plural form of premise is “premises.”

Here is an example of how “premises” can be used in a sentence:

“In a syllogism, it is crucial that both premises support the argument’s conclusion.”

What is the meaning of basic premise?

A basic premise is a fundamental assumption or principle that serves as the foundation of an argument or theory. Basic premises are often implicit and taken for granted, serving as starting points from which logical deductions or inferences are made (e.g., “We assume, as a basic premise, that causing unnecessary suffering is morally wrong).

What is the definition of premise?

A premise is the basis for an argument. It is a foundational element upon which further conclusions or deductions are made. Premises play an especially important role in syllogisms, which express deductive reasoning.

Is this article helpful?
Magedah Shabo

Magedah is the author of Rhetoric, Logic, & Argumentation and Techniques of Propaganda and Persuasion. She began her career in the educational publishing industry and has over 15 years of experience as a writer and editor. Her books have been used in high school and university classrooms across the US, including courses at Harvard and Johns Hopkins. She has taught ESL from elementary through college levels.