Tautological has the “common” meaning of trivial and in logic is a technical term: **a statement which is true regardless of the truth or falsity of its constituent propositions**. 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).

## What are tautological statements?

1a : **needless repetition of an idea, statement, or word** Rhetorical repetition, tautology (‘always and for ever’), banal metaphor, and short paragraphs are part of the jargon.— Philip Howard. b : an instance of such repetition The phrase “a beginner who has just started” is a tautology.

## What is tautological truth?

A Tautology is **a statement that is always true because of its structure**—it requires no assumptions or evidence to determine its truth. A tautology gives us no genuine information because it only repeats what we already know.

## What does consistency mean in logic?

Logical consistency. Definition: **a set of sentences is logically consistent if and only if it is possible for all the members of that set to be true**. A consistent set of sentences is a set all of which can be true together — or, as logicians are fond of saying: there is some possible world in which they are all true.

## What is consistency in propositional logic?

Two or more propositions are logically consistent **if it is possible for them to all be true at the same time**. If there is no way for them all to be true at once, they are inconsistent . Inconsistent propositions are said to contradict one another.

## What is tautology and contradiction?

A tautology is an assertion of Propositional Logic that is true in all situations; that is, it is true for all possible values of its variables. A contradiction is an assertion of Propositional Logic that is false in all situations; that is, it is false for all possible values of its variables.