Definition:Valid Argument

Definition
A valid argument is a logical argument in which the premises provide conclusive reasons for the conclusion.

When a proof is valid, we may say one of the following:
 * The conclusion follows from the premises;
 * The premises entail the conclusion;
 * The conclusion is true on the strength of the premises;
 * The conclusion is drawn from the premises;
 * The conclusion is deduced from the premises;
 * The conclusion is derived from the premises.

Proof
If all the premises of a valid argument are true, then the conclusion must also therefore be true.

It is not possible for the premises of a valid argument to be true, but for the conclusion to be false.

Also known as
A valid argument is also known as a truth preserving argument.

Likewise, validity is also known as truth preservation.

Some authors use the term sound argument to mean the same thing that is defined here as a proof.

However, as some use sound argument to mean the same thing as a valid argument, it is recommended that this term not be used.

Also see

 * Definition:Invalid Argument

Warning
In natural language, it is commonplace to discuss the nature of statements as being valid or invalid, when what is really meant is that a statement is either true or false.