The following is from: https://www.thoughtco.com/premise-argument-1691662
A premise is a proposition upon which an argument is based or from which a conclusion is drawn. Put another way, a premise includes the reasons and evidence behind a conclusion, says Study.com.
A premise may be either the major or the minor proposition of a syllogism—an argument in which two premises are made and a logical conclusion is drawn from them—in a deductive argument. Merriam-Webster gives this example of a major and minor premise (and conclusion):
“All mammals are warmblooded [major premise]; whales are mammals [minor premise]; therefore, whales are warmblooded [conclusion].”
The term premise comes from medieval Latin, meaning “things mentioned before.” In philosophy as well as fiction and nonfiction writing, the premise follows largely the same pattern as that defined in Merriam-Webster. The premise—the thing or things that came before—lead (or fail to lead) to a logical resolution in an argument or story.
Premises in Philosophy
To understand what a premise is in philosophy, it helps to understand how the field defines an argument, says Joshua May, an associate professor of philosophy at the University of Alabama, Birmingham. In philosophy, an argument is not concerned with disputes among people; it is a set of propositions that contain premises offered to support a conclusion, he says, adding:
“A premise is a proposition one offers in support of a conclusion. That is, one offers a premise as evidence for the truth of the conclusion, as justification for or a reason to believe the conclusion.”
May offers this example of a major and minor premise, as well as a conclusion, that echoes the example from Merriam-Webster:
- All humans are mortal. [major premise]
- G.W. Bush is a human. [minor premise]
- Therefore, G.W. Bush is mortal. [conclusion]