Validity

Validity of an argument refers to its logical structure and does not necessarily indicate that the argument has truth value. That is, the conclusion of a valid argument follows logically from the premises even when the premises are inaccurate.


□ All men are mortal
□ Socrates is a man
□ Therefore, Socrates is mortal.


A valid argument cannot possibly lead from true premises to a false conclusion, though an argument that leads from false premises to a false conclusion can have a logically valid form.


□ All men are immortal
□ Socrates is a man
□ Therefore, Socrates is immortal

Invalid arguments can lead from true premises to a true conclusion, but they do not do so with a valid logical form. However, invalid arguments can also lead from true premises to false conclusions.


□ All men are mortal
□ Socrates is mortal
□ Therefore, Socrates is a man

(Socrates the famous Greek philosopher was indeed a mortal man, but 'Socrates' could also be the name of a woman, or a dog, or a pet pig.)

Deductive arguments set out to demonstrate that a conclusion is true, whereas inductive arguments set out to demonstrate a conclusion is probably true.

No comments: