Contingent truths are true in this world, but could have turned out otherwise (in other words, they are false in at least one possible world). Treating logical truths, analytic truths, and necessary truths as equivalent, logical truths can be contrasted with facts (which can also be called contingent claims or synthetic claims). However, the question of whether any statements are necessarily true remains the subject of continued debate. The view that logical statements are necessarily true is sometimes treated as equivalent to saying that logical truths are true in all possible worlds. This is to say that they are such that no situation could arise in which they could fail to be true. Logical truths are generally considered to be necessarily true.

All of philosophical logic can be thought of as providing accounts of the nature of logical truth, as well as logical consequence. Logical truths are thought to be the simplest case of statements which are analytically true (or in other words, true by definition). Thus, logical truths such as 'if p, then p' can be considered tautologies. In other words, a logical truth is a statement which is not only true, but one which is true under all interpretations of its logical components (other than its logical constants).

Broadly speaking, a logical truth is a statement which is true regardless of the truth or falsity of its constituent propositions. Logical truth is one of the most fundamental concepts in logic.

This article is about propositions which are logically true.

Language truth and logic