What is the validity of the truth

The wiki for philosophy

An argument is valid when the truth of its premises guarantees the truth of its conclusion. In this expression it becomes clear that the validity of arguments depends solely on their logical form.



(1) All people are mortal. (Thesis)

(2) Socrates is a human. (Premise)

(3) So Socrates is human. (Conclusion)


(1) All planets are round. (Thesis)

(2) The earth is a planet. (Premise)

(3) So the earth is round. (Conclusion)

The following logical form can be worked out for both arguments:

(1) P.

(2) Q.

(3) R.

Arguments A and B are valid because all arguments of the same logical form (all structurally identical arguments) with true premises also have a true conclusion.

In general, validity applies when it is impossible that the premises are (at the same time) true and the conclusion is false. It does not matter whether the premises and conclusions are actually true or false, it is all about the logical form. One then speaks of one formally valid Argument.

Formally valid arguments are valid regardless of the topic. Their validity is based only on “formal” elements that can be applied to any topic (e.g. the logical form worked out here).

Example of a valid but not formally valid argument:

(1) Markus is a bachelor.

(2) So Markus is not married.