Premise - promise

Premise and Promise are sometimes confused. Because neither is unusual in formal writing, and both are recognised by spell-checkers, each may be mis-typed for the other. Do not make this confusion. (You may also want to see advice on the spelling and pronunciation of premise and, separately, promise.

• Premise comes from a Latin word (praemissus) meaning '[that which has been] put before'. The basic use of the noun 'a premise' is in logic and related subjects. It means the basic idea behind a statement or thought, sometimes called 'a proposition'. In particular, a premise is one of the two starting points of a syllogism. This is the form of argument of which an often-quoted example is:

All humans are mortal (the major premise);

Socrates is human (the minor premise);

Therefore Socrates is mortal (the conclusion).

In the formal study of logic - and nowhere else these days - this is sometimes spelled premiss.

• More generally, a premise is a basis for a chain of thought, or the start of a logical argument. There is a related verb, 'to premise, which means 'to treat as a premise', that is, 'to base your argument upon', or 'to take as given'.
  • In Law, it often means 'the aforesaid', or 'what has been said before'. As a result, (and an etymological curiosity) premises are buildings, land and enclosures etc. This plural word premises began as meaning 'a description put before', i.e. at the start of the document, which described the landed property or real estate to which a given legal document referred. Such documents are often letting agreements, contracts, sales or conveyances.
• The noun 'a promise', on the other hand, is a commitment to do something (e.g. a promise to marry). There is also the related verb, 'to promise', which means to make such a commitment ("He promised her to marry her") , or an assurance of the truth of something said ("It's happened, I promise you"). When one promises to do something, one is giving one's word, a solemn assurance that one is committed to the matter in hand. This has been extended into a wider and more general use: if a teacher reports that a student "shows promise", the indication is of "strong or reasonable grounds for the expectation of future achievements or good results; the quality of potential excellence" (OED). From this there comes the adjective promising: "The current research seems most promising."